Dissertations / Theses: 'Antifungal and antibacterial activity'

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Mohammadihashemi, Marjan. "Antibacterial and Antifungal Activity of Ceragenins, Mimics of Endogenous Antimicrobial Peptides." BYU ScholarsArchive, 2019. https://scholarsarchive.byu.edu/etd/7411.

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The continuous emergence of drug-resistance pathogens is a global concern. As a result, substantial effort is being expended to develop new therapeutics and mechanisms for controlling microbial growth to avoid entering a "post-antibiotic" era in which commonly used antibiotics are no longer effective in treating infections. In this work, we investigate the efficacy and application of ceragenins as non-peptide mimics of antimicrobial peptides (AMPs). First, this work examines the susceptibility of drug-resistant Gram-negative bacteria. The susceptibility of colistin-resistant clinical isolates of Klebsiella pneumoniae to ceragenins and AMPs suggests that there is little to no cross-resistance between colistin and ceragenins/AMPs. Furthermore, Lipid A modifications are found in bacteria with modest changes in susceptibility to ceragenins and with high levels of resistance to colistin. Next, we investigated the potential for cross resistance between chlorhexidine, colistin, AMPs and ceragenins as repeated exposure of bacteria to chlorhexidine might result in cross resistance with colistin, AMPs or ceragenins. Furthermore, a proteomics study on the chlorhexidine-resistant strains showed that chlorhexidine resistance is associated with upregulation of proteins involved in the assembly of LPS for outer membrane biogenesis and virulence factors in Pseudomonas aeruginosa.Second, this dissertation describes the antifungal activity of ceragenins against an emerging multidrug-resistant fungus, Candida auris. We found that lead ceragenins displayed activities comparable to known antifungal agents against C. auris isolates. We also found that fungal cell morphology was altered in response to ceragenin treatment, that ceragenins exhibited activity against sessile organisms in biofilms, and that gel and cream formulations including CSA-44 and CSA-131 resulted in a significant log reduction against established fungal infections in ex vivo mucosal tissues. Finally, a hydrogel film containing CSA-131 was generated on endotracheal tubes (ETTs). ETTs provide an abiotic surface on which bacteria and fungi form biofilms that cause serious infections. In this study, the eluting ceragenin prevented fungal and bacterial colonization of coated ETTs for extended periods while uncoated tubes were colonized by bacteria and fungi. Coated tubes were well tolerated in intubated pigs. The ability of ceragenins to eradicate established biofilms make them attractive potential therapeutics for persistent infections in the lung, including those associated with cystic fibrosis. In ex vivo studies, we initially found that this ceragenin, at concentrations necessary to eradicate established biofilms, also causes loss of cilia function. However, by formulating CSA-131 in poloxamer micelles, cilia damage was eliminated and antimicrobial activity was unaffected. These findings suggest that CSA-131, formulated in micelles, may act as a potential therapeutic for polymicrobial and biofilm-related infections in the lung and trachea.

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Mogashoa, Motanti Mary. "Isolation and characterisation of antifungal and antibacterial compounds from Combretum molle (Combretaceae) leaf extracts." Diss., University of Pretoria, 2017. http://hdl.handle.net/2263/60270.

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The main aim of this study was to isolate and characterise antifungal and antibacterial compounds from leaf extracts of Combretum molle which belonging to the Combretaceae family. C. molle is one of the commonly used medicinal plants in southern Africa for numerous ailments. Three animal fungal pathogens, namely, Candida albicans, Cryptococcus neoformans, Aspergillus fumigatus and five plant fungal pathogens, namely, Aspergillus niger, Aspergillus parasiticus, Fusarium oxysporum, Penicillium janthinellum, Rhizoctonia solani and four nosocomial bacteria Staphylococcus aureus, Enterococcus faecalis, Escherichia coli and Pseudomonas aeruginosa were used as test microorganisms for bioactive compounds in leaf extracts of C.molle. Experiments for phytochemical analysis were done using different C. molle leaf extracts which were made using acetone, methanol, ethanol, ethyl acetate, chloroform, butanol and hexane as extractants. Thin Layer Chromatography (TLC) fingerprints of different leaf extracts were developed in three mobile phase systems, EMW, CEF and BEA and detected with vanillin-sulphuric acid spraying agent. The different extracts of C. molle showed the presence of many different compounds with distinct retardation factors (Rf), separated according to their polarities. Bioautography was carried out to determine the number of active compounds and their Rf values. The TLC plates were developed in three mobile systems, each sprayed with either fungal or bacterial strains. In BEA bioautograms of A. fumigatus, clear zones of inhibition were observed at Rf values of 0.12, 0.23, and 0.40. In EMW bioautogram of C. albicans, clear zones of inhibition were observed at Rf value of 0.73, 0.81, 0.87. C. neoformans had weak growth inhibition. Most of the fungal and bacterial strains tested in the bioautography displayed susceptibility to the active compounds, with P. janthinellum and P. aeruginosa showing exceptional sensitivity. The minimum inhibitory concentrations (MIC) values ranged from 0.02 to 2.5 mg/ml against the tested pathogens. The acetone and ethyl acetate extracts had the best inhibitory activity against P. janthinellum with an MIC value of 0.02 mg/ml. The acetone extract of C. molle gave the highest total activity (775 ml/g) against P. janthinellum. C. albicans was the most resistant pathogen with an average MIC value of 0.56 mg/ml compared with the other tested strains. Extracts were active against both Gram-positive and Gram-negative strains. P. aeruginosa extracts had the highest average MIC value (0.24 mg/ml) among the tested bacterial strains. In general, there was good overall inhibitory activity by different extracts of C. molle. Bioassay-guided fractionation of DCM extract of the leaves of C. molle yielded 32 fractions. Further fractionation led to the isolation of five compounds (C1, C2, C3, C4 and C5). Compound C1 was selected for structure elucidation due a larger quantity isolated and higher antimicrobial activity compared with the other isolated compounds. Nuclear magnetic resonance (NMR) spectroscopy and mass spectroscopy (MS) was used to show that compound C1 was taraxerol, belonging to the taraxerane group. Antimicrobial activity of the isolated compound against P. janthinellum had an MIC value of 0.08 ug/ml. Although the compound taraxerol have been discovered in other plant species, it is reported for the first time from C. molle in the study. The results illustrate that crude extracts and compound taraxerol from C. molle can be used as either an antibacterial or antifungal, and warrants further investigation.
Dissertation (MSc)--University of Pretoria, 2017.
Paraclinical Sciences
MSc
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Alasmary, Fatmah A. S. "Synthesis and evaluation of selected benzimidazole derivatives as potential antimicrobial agents. An investigation into the synthesis of substituted benzimidazoles and their evaluation in vitro for antimicrobial activity." Thesis, University of Bradford, 2013. http://hdl.handle.net/10454/6325.

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Microbe resistence is a serious issue, especially as they have become resistant to most well known drugs. Therefore this is considered as a global problem and is now dealt with at a poitical level. Since no new classes of antimicrobial agents have been discovered in the past three deacdes, the development of new drugs is extremely urgent. Therefore the aim of this project was to synthesise derivatives of benzimidazole, and then assesses their antimicrobial activities in vitro by using disc (well) diffusion and MICs tests. A total of 69 benzimidazole derivatives, with substituents at positions 1, 2, and 5, were synthesised, characterised and tested against selected bacteria and fungi. In addition, six bezimidazole silver complexes were prepared and evaluated for their antimicrobial behavior. The SAR showed that the antimicrobial activity of the compounds depended on the substituents attached to the bicyclic heterocycle. Some promising results were obtained. In particular, 5 compounds displayed antibacterial activity against two MRSA strains with MIC values corresponding to ciprofloxacin, which can be considered significant. The compounds have some common features; four possess 5-chloro or 5-bromo substituents; two are derivatives of (S)-2- ethanaminebenzimidazole and the others are derivative of one 2-(chloromethyl)-1Hbenzo[d]imidazole, (1H-benzo[d]imidazol-2-yl)methanethiol and 2-(methoxymethyl)-1-methyl-1H-benzo[d]imidazole. The results from the antifungal screening were very interesting as there were 26 compounds, including two silver complexes, which were potent fungicides against the selected fungal species. They showed equivalent or greater potentency in their MIC values than amphotericin B. In particular, the 5-fluoro, 5-chloro and 5-bromo benzimidazole showed broad spectrum activity.
Saudi Culture Bureau and King Saud University

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Alasmary, Fatmah Ali Saeed. "Synthesis and evaluation of selected benzimidazole derivatives as potential antimicrobial agents : an investigation into the synthesis of substituted benzimidazoles and their evaluation in vitro for antimicrobial activity." Thesis, University of Bradford, 2013. http://hdl.handle.net/10454/6325.

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Microbe resistence is a serious issue, especially as they have become resistant to most well known drugs. Therefore this is considered as a global problem and is now dealt with at a poitical level. Since no new classes of antimicrobial agents have been discovered in the past three deacdes, the development of new drugs is extremely urgent. Therefore the aim of this project was to synthesise derivatives of benzimidazole, and then assesses their antimicrobial activities in vitro by using disc (well) diffusion and MICs tests. A total of 69 benzimidazole derivatives, with substituents at positions 1, 2, and 5, were synthesised, characterised and tested against selected bacteria and fungi. In addition, six bezimidazole silver complexes were prepared and evaluated for their antimicrobial behavior. The SAR showed that the antimicrobial activity of the compounds depended on the substituents attached to the bicyclic heterocycle. Some promising results were obtained. In particular, 5 compounds displayed antibacterial activity against two MRSA strains with MIC values corresponding to ciprofloxacin, which can be considered significant. The compounds have some common features; four possess 5-chloro or 5-bromo substituents; two are derivatives of (S)-2- ethanaminebenzimidazole and the others are derivative of one 2-(chloromethyl)-1Hbenzo[d]imidazole, (1H-benzo[d]imidazol-2-yl)methanethiol and 2-(methoxymethyl)-1-methyl-1H-benzo[d]imidazole. The results from the antifungal screening were very interesting as there were 26 compounds, including two silver complexes, which were potent fungicides against the selected fungal species. They showed equivalent or greater potentency in their MIC values than amphotericin B. In particular, the 5-fluoro, 5-chloro and 5-bromo benzimidazole showed broad spectrum activity.

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Ževžikovienė, Augusta. "Naujų 4-tiazolidinonų, turinčių sulfanilamido, alilamino ir nitrofurano farmakoforus, priešmikrobinių savybių tyrimas." Doctoral thesis, Lithuanian Academic Libraries Network (LABT), 2012. http://vddb.laba.lt/obj/LT-eLABa-0001:E.02~2012~D_20120918_161940-39143.

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Klinikinėje praktikoje infekcinėms ligoms gydyti vartojama daugiau kaip 200 priešmikrobinių medžiagų, tačiau infekcinės ligos yra viena dažniausių mirties priežasčių ir naujų priešmikrobinių vaistų poreikis nemažėja. Modifikuojant 4-tiazolidinono žiedą susintetinami įvairaus biologinio aktyvumo junginiai. 4-tiazolidinono dariniai su sulfanilamido farmakoforu yra aktyvesni už sulfanilamidus prieš bakterijas ir pasižymi priešgrybeliniu poveikiu; su nitrofurano farmakoforu yra vieni aktyviausių priešmikrobinių junginių. Alilaminą įjungus į molekulę kartu su jau anksčiau žinomais farmakoforais, tikėtąsi geresnio naujų junginių priešmikrobinio aktyvumo. Pritaikius pasirinktas metodikas naujų 4-tiazolidinono darinių su pasirinktų farmakoforų (sulfanilamido, nitrofurano, alilamino) struktūriniais fragmentais sintezei, susintetinti 39 4-tiazolidinono ciklą turintys junginiai. Įvertinus fiziko-chemines savybes ir toksiškumo riziką in silico, nustatyta junginių, kaip biologiškai aktyvių medžiagų, vertė. In silico ir in vitro patvirtinta, kad nauji 4-tiazolidinono dariniai su sulfanilamido, nitrofurano ir alilamino farmakoforais pasižymi prieš¬mikrobinėmis savybėmis prieš skirtingas bakterijų (S. aureus, E. faecalis, E. coli, P. aeruginosa, K. pneumonia, B. subtilis, P. mirabilis) ir grybelio C.albicans kultūras. Apibendrinus mikrobiologinių tyrimų rezultatus, nustatyti aktyviausi antibakteriniai ir priešgrybeliniai junginiai.
More than 200 antimicrobial agents are used in clinical practice for the treatment of infectious diseases, however, infectious diseases are still one of the most common causes of death, and the need for new antimicrobials isn’t decreasing. Compounds with different biological activity are synthesized by modifying 4-thiazolidinone. 4-thiazolidinones with sulfanilamide pharmacophore are more active against bacteria than sulfanilamides, and are characterized as antifungals. 4-thiazolidinones with nitrofuran pharmacophore are one of the most active antimicrobials. Higher antimicrobial activity of new compounds was expected after attaching allylamine to the molecule together with the previously known pharmacophores. By applying the selected methodologies for the synthesis of new 4-thiazolidinones with the fragments of selected pharmacophores (sulfanilamide, nitrofurane, allylamine), 39 derivatives of 4-thiazolidinone were synthesized. The assessment of physico-chemical properties and toxicity risk in silico helped to determine the value of compounds as biologically active substances. In silico and in vitro studies confirmed that new 4-thiazolidinone’s with sulfanilamide, nitrofurane and allylamine pharmacophores showed antimicrobial activity against various bacteria (S. aureus, E. faecalis, E. coli, P. aeruginosa, K. pneumonia, B. subtilis, P. mirabilis) and fungal cultures of C.albicans. Summarising microbiological tests, the most active antibacterial and antifungal compounds... [to full text]

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Peter, Cristina Mendes. "Atividade antimicrobiana de extratos hidroalcoólicos de própolis marrom, verde e de abelhas jataí (Tetragonisca angustula) frente a micro-organismos infecciosos de interesse em Medicina Veterinária e Humana." Universidade Federal de Pelotas, 2015. http://repositorio.ufpel.edu.br:8080/handle/prefix/3379.

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O objetivo deste estudo foi avaliar a atividade antimicrobiana (antibacteriana, antifúngica e antiviral), toxicidade celular e composição química de extratos hidroalcoólicos da própolis marrom (PM), verde (PV) e de abelhas nativas jataí (PJ). A atividade antibacteriana da própolis foi analisada pelo método de Microdiluição frente à Staphylococcus aureus, Streptococcus dysgalactiae, Streptococcus uberis, Streptococcus agalactiae e Escherichia coli. Para a atividade antifúngica, foi utilizada metodologia semelhante, frente à Candida lipolytica, Candida parapsilosis, Sporothrix schenckii e Sporothrix brasiliensis. A atividade antiviral foi avaliada através de dois métodos distintos de tratamento das células com os extratos: antes e depois da inoculação viral, frente ao Herpes Vírus Bovino (BoHV-1) e ao Vírus da Diarreia Viral Bovina (BVDV) e quantificado pelo teste de MTT (3-(4,5 dimetiltiazol-2yl)- 2-5-difenil-2H tetrazolato de bromo) e a atividade virucida, avaliada através de diferentes diluições dos vírus, temperaturas e tempos de incubações e analisadas por observação microscópica e quantificadas através da Dose Infectante (D.I.) 50%. A toxicidade foi avaliada através de diferentes concentrações e a viabilidade celular quantificada por MTT. À composição química das própolis foi determinada por Cromatografia Líquida de Alta Eficiência (CLAE). Os resultados da atividade antibacteriana demonstraram que PM obteve valores menores de Concentração Inibitória Mínima (CIM) e Concentração Bactericida Mínima (CBM), quando testados frente à S. aureus (6,7 mg/mL; 13,4 mg/mL, respectivamente), e E. coli (29,4 mg/mL; 54,3 mg/mL) quando comparados ao PV e PJ. Contudo frente Streptococcus sp., os menores valores de CIM e CBM encontrados foram da PV (p<0,01). Na atividade antifúngica as PM, PV e PJ apresentaram eficácia à Candida sp. eSporotrix sp. A PJ apresentou menor toxicidade, em sequência PV e PM. Na atividade antiviral, os extratos foram mais eficazes quando acrescentados no pré-tratamento e a PM e PV foram mais eficazes ao BoHV-1, enquanto a PJ ao BVDV. Na virucida, a PVa 37°C obteve valores diferentes e menores (log = 2,67) em relação a PM (log = 3,5) e PJ (log = 3,76). No entanto, para BVDV a PJ apresentou os melhores resultados para ambas temperaturas. Os resultados demonstram o potencial da própolis como antimicrobiano no tratamento de doenças em Medicina Veterinária e Humana.
The objective of this study was to evaluate the antimicrobial activity (antibacterial, antifungal and antiviral), cell toxicity and chemical composition of hydroalcoholic extracts of brown propolis (PM), green (PV) and native bees jataí (PJ). The antibacterial activity of propolis was analyzed by microdilution method against the Staphylococcus aureus, Streptococcus dysgalactiae, Streptococcus uberis, Streptococcus agalactiae and Escherichia coli. For the antifungal activity, similar methodology was used, compared to Candida lipolytica, Candida parapsilosis, Sporothrix schenckii and Sporothrix brasiliensis. The antiviral activity was measured using two different methods of treatment of the cells with the extracts: before and after the viral inoculation against Bovine Herpes virus (bovine herpesvirus type 1) and Bovine Viral Diarrhea Virus (BVDV) and quantitated by assaying MTT (3- (4,5 dimethylthiazol-2yl) - 2,5-diphenyl-2H-tetrazolato bromine) and virucidal activity, measured using different dilutions of virus, temperatures and incubation times and analyzed by microscopic observation and quantified by the infective dose (ID) 50%. Toxicity was evaluated using different concentrations and cell viability measured by MTT. In the chemical composition of propolis was determined by High Performance Liquid Chromatography (HPLC) methods. The results demonstrated that the antibacterial activity had lower values PM Minimum Inhibitory Concentration (MIC) and Minimum Bactericidal Concentration (MBC) when tested against S. aureus (6.7 mg/mL; 13.4 mg/mL, respectively) and E. coli (29.4 mg/mL, 54.3 mg/mL) compared to the PV and PJ. However front Streptococcus sp., the lowest values of MIC and MBC were found of PV (p <0.01). In the antifungal activity PM, PV and PJ showed efficacy to Candida sp. and Sporotrix spp. The PJ showed lower toxicity in PV and PM sequence. In the antiviral activity, the extracts were more effective when added in the pre treatment and the PM and PV were more effective in BoHV-1, while the PJ to BVDV. In virucidal, PV obtained at 37°C and under different values (log = 2.67) compared to PM (log = 3.5) and PJ (log = 3.76). However, for BVDV PJ showed the best results for both temperatures. Results show the potential of propolis as an antimicrobial in the treatment of diseases in Veterinary Medicine and Human.

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Camargo, Marlene Rodrigues Marcelino. "Avaliação da atividade antimalárica e antimicrobiana de geissosperum argenteum Woodson e Minguartia guianensis Aubl coletadas em Roraima." Universidade Federal de Roraima, 2011. http://www.bdtd.ufrr.br/tde_busca/arquivo.php?codArquivo=130.

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Dentre as espécies florestais nativas da Amazônia utilizadas por populações tradicionais na terapêutica de diversos problemas de saúde estão a Geissospermum argenteum Woodson, uma Apocynaceae, e a Minquartia guianensis Aubl., da família Olacaceae. Entre os problemas de saúde está a malária, que no Brasil e no mundo ainda é um grave problema de saúde pública. Outro agravo à saúde de importância são infecções microbianas, pois os micro-organismos têm desenvolvido resistência aos agentes antimicrobianos. Neste trabalho, foram coletadas amostras de cascas, folhas e galhos de G. argenteum e M. guianensis, em área de floresta, na Vila Apiaú, município de Mucajaí RR. As amostras foram submetidas à extração metanólica a quente e extração aquosa, Amostra de extrato metanólico de cascas de G. argenteum foi submetida a particionamento líquido-líquido, resultando nas frações hexânica, clorofórmica, acetato de etila e metanol/água. A fração clorofórmica foi selecionada para cromatografia em coluna com sistema gradiente de solventes, obtendo-se 38 frações, as quais foram analisadas através de CCD e destas a fração Cr10 foi selecionada para cromatografia preparativa, a partir da qual foi obtida a fração F6, que analisada em CCD mostrou-se positiva para alcalóides. Os extratos metanólicos e aquosos de ambas as espécies, e frações primárias provenientes de extratos G. argenteum foram testados em ensaios in vitro para atividade antimalárica frente à cepa cloroquino-resistente, K1, de Plasmodium falciparum, nas concentrações de 50 e 5 μg/mL. Posteriormente, amostras ativas foram avaliadas em 7 diluições para estabelecer a relação dose-resposta e valores de concentração inibitória mediana (CI50). Amostras provenientes das duas espécies também foram testadas contra as cepas bacterianas, Staphylococcus aureus, Streptococcus mutans e Escherichia coli, e contra a levedura Candida albicans. A atividade antimicrobiana foi avaliada através de difusão em ágar e a concentração inibitória mínima (CIM) por microdiluição em placas. Para as frações acetato de etila, clorofórmica, hexânica e hidroalcoólica obtida de cascas de G. argenteum e a fração Cr10 foi realizada a bioautografia para S. aureus. Na atividade antimalárica o extrato metanólico de casca foi ativo, com CI50 de 4,6 μg/mL e a fração clorofórmica obtida de casca de G. argenteum também foi ativa com CI50 de 2,0 μg/mL. Os extratos de M. guianensis foram considerados inativos para a atividade antimalárica. Na atividade antimicrobiana, através de difusão em ágar, extratos de G. argenteum foram parcialmente ativos contra S. aureus, S. mutans e inativos contra E. coli e C. albicans. A CIM para S. aureus foi de 0,63 mg/mL para a fração metanol/água, para S. mutans, CIM de 0,63 mg/mL e C. albicans com CIM de 0,63 mg/mL. Para cepa de E. coli os extratos foram inativos. Extratos de M. guianensis mostraram-se ativos frente à S. aureus e C. albicans através de difusão em ágar e apresentaram a CIM superior a 1mg/ml para S. aureus, S. mutans e C. albicans. Os extratos de M. guianensis foram inativos contra E. coli. Na autobiografia para S. aureus as frações testadas apresentaram atividade.
Among the natives species from the Amazon Forest used by traditional populations in the treatment of various health problems, including, malaria, wich in Brazil and in the world remains a serious public health problem, are Geissospermum argenteum Woodson, an Apocynaceae, and Minquartia guianensis Aubl, Olacaceae family. Another important health problem is the microbial infections, because the microorganisms have developed resistence to antimicrobial agents. In this work, samples were collected from bark, leaves and twigs of G.argenteum and M. guianensis in a forestall area in Apiaú village, city of Mucajaí RR. The samples were extracted by hot methanol and water extraction, resulting in methanol and aqueous extracts. Sample of methanol extract of bark of G.argenteum was submitted to liquid-liquid partitioning, resulting in fractions hexane, chloroform, ethyl acetate and methanol/water. The chloroform fraction was selected for fractionation using chromatography colunn and solvent gradient system, resulting in 38 fractions, which were analyzed by TLC and the fraction Cr10 was selected for preparative chromatography, from which the fraction F6 was obtained, analyzed in CCD was positive for alkaloids. The methanol and aqueous extracts of both species and fractions of extracts from primary G.argenteum were tested in vitro assays for antimalarial activity against the chlroquine-resistant K1 Plasmodium falciparum at concentrations of 50 and 5 mg/mL. Subsequently, active samples were evaluated in 7 diluitions to establish the dose-response and median inhibitory concentration values (IC50). Samples from two species were also tested against bacterial strains, Staphylococcus aureus, Streptococcus mutans and Escherichia coli, and against the yeast Candida albicans. Antimicrobial activity was evaluated by agar diffusion and minimum inhibitory concentration (MIC) by microdilution plates. For fractions of ethyl acetate, chloroform, hexane and water-alcohol obtained from barks of G.argenteum, fraction Cr10 and bioautography was performed fo S. aureus. Antimalarial activity in the methanol extract of bark was active, with IC50 of 4,6 mg/mL and chloroform fraction obtained from bark of G.argenteum was also active with IC50 of 2,0 mg/mL. The extracts of M. guianensis were considered inactive for antimalarial activity. In antimicrobial activity by agar diffusion, extracts of G.argenteum were partially active against S. aureus, S. mutans and inactive against E. coli and C. albicans. The MIC for S. aureus was 0,63 mg/mL per fraction methanol/water, S. mutans, MIC of 0,63 mg/mL and C. albicans with an MIC of 0,63 mg/mL. For the strain of E.coli there was no activity. Extracts of M. guianensis were active against the S. aureus and C. albicans by agar diffusion and presented more than 1 mg/mL MIC for S aureus, S.mutans and C. albicans. The extracts of M. guianensis were inactive against E. coli.

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Cunha, Let?cia Figueiredo. "Plantas do cerrado brasileiro: triagem fitoqu?mica e de atividades biol?gicas de esp?cies nativas do munic?pio de Diamantina, regi?o do Vale do Jequitinhonha, Minas Gerais." UFVJM, 2016. http://acervo.ufvjm.edu.br/jspui/handle/1/1433.

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?rea de concentra??o: Ci?ncias farmac?uticas.
Data de aprova??o ausente.
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As plantas, por serem fonte de subst?ncias biologicamente ativas, s?o utilizadas com a finalidade terap?utica desde o in?cio da civiliza??o humana. O Brasil, por sua vez, ? detentor de uma vasta diversidade biol?gica e possui uma grande quantidade de esp?cies vegetais com potencial medicinal. Dentre os diversos biomas do territ?rio brasileiro, o Cerrado representa o segundo maior, registrando-se muitas esp?cies medicinais. Apesar de sua rica biodiversidade muitas plantas end?micas deste bioma foram pouco estudadas do ponto de vista qu?mico e biol?gico. Consequentemente, ? necess?rio maior investimento em pesquisas com plantas medicinais para tratamento de doen?as, principalmente, as cr?nicas degenerativas e parasit?rias, como Doen?a de Chagas, Leishmanioses, C?ncer e as infec??es causadas por bact?rias e fungos, cujo o tratamento apresenta importantes limita??es. Assim, o objetivo deste estudo foi realizar a triagem fitoqu?mica e de atividades biol?gicas de extratos etan?licos de 12 esp?cies de plantas oriundas do Cerrado, coletadas no mun?cipio de Diamantina, Vale do Jequitinhonha/MG. Para a triagem fitoqu?mica preliminar destes extratos foram realizadas rea??es cromog?nicas, de precipita??es e an?lises em cromatografia em camada delgada comparativa (CCDC). A citotoxicidade para c?lulas normais de mam?feros foi avaliada em fibroblastos de camundongos (L929). A linhagem celular de c?ncer de mama MDA-MB-231 foi a utilizada para a avalia??o da atividade antitumoral dos extratos. A avalia??o da atividade antitripanossomat?deo foi realizada sobre formas epimastigotas da cepa Colombiana de Trypanossoma cruzi e, sobre as formas promastigotas das cepas BH46 de Leishmania (leishmania) infantum e cepa M2269 de Leishmania (leishmania) amazonensis. Para a avalia??o destas atividades foi empregada a t?cnica colorim?trica de MTT. A avalia??o das atividades antibacteriana e antif?ngica foi realizada por meio da determina??o da Concentra??o Inibit?ria M?nima (CIM), empregando a t?cnica colorim?trica da Resazurina. As esp?cies de bact?rias utilizadas foram Escherichia coli, Proteus mirabilis, Pseudomonas aeruginosa e Staphylococcus aureus. Na atividade antif?ngica foram utilizadas quatro esp?cies de leveduras (Candida albicans, Candida famata, Candida krusei e Candida tropicalis) e duas esp?cies de fungos filamentosos (Aspergillus niger e Penicillium expansum). Dos 13 extratos avaliados com rela??o a citotoxicidade sobre fibroblastos de camundongos da linhagem L929, todos apresentaram algum grau de citotoxicidade. Alguns destes extratos apresentaram elevada toxicidade sobre esta linhagem celular, sendo que o extrato etan?lico das folhas de E. erythropappus foi o mais t?xico. Na avalia??o da atividade antitumoral, com exce??o do extrato etan?lico das folhas de P. rigida, todos os outros extratos avaliados apresentaram atividade. Destes o mais promissor tamb?m foi o extrato etan?lico das folhas de E. erythropappus. Na avalia??o da atividade tripanocida sobre formas epimastigotas da cepa Colombiana de T. cruzi, nove extratos foram ativos contra este parasito. Destes os mais promissores foram os extratos das folhas de A. aculeata e das folhas de E. erythropappus. Na avalia??o da atividade leishmanicida para a cepa M2269 os extratos etan?licos das folhas de E. erythropappus e das folhas de B. oxyclada apresentaram como os mais promissores e, para a cepa BH46 o extrato etan?lico de toda esp?cie T. catahartica foi o mais promissor, seguido tamb?m do extrato etan?lico das folhas de E. erythropappus. Na avalia??o da atividade antibacteriana somente os extratos etan?licos das folhas de B. oxyclada, de P. tomentosa e S. rugosa foram ativos e, as ?nicas bact?rias sens?veis foram P. aeruginosa e S. aureus. Destes o extrato etan?lico de P. tomentosa inibiu um maior n?mero de bact?rias com a??o bactericida. Os fungos filamentosos, A. niger e P. expansum, se mostraram resistentes a todos os extratos avaliados e C. krusei foi a levedura mais sens?vel. Os extratos das folhas de B. oxyclada e das folhas de P. tomentosa foram os extratos que inibiram o maior n?mero de esp?cies f?ngicas com os menores valores de CIM. Atrav?s destes resultados, sugere-se que os extratos etan?licos das folhas de Eremanthus erythropappus, de Peixotoa tomentosa e de Banisteriopsis oxyclada apresentaram o maior n?mero de atividades biol?gicas e com os melhores resultados, o que torna estas esp?cies as mais promissoras como fontes potenciais de mol?culas bioativas para o tratamento de C?ncer, Doen?a de Chagas, Leishmanioses e infe??es bacterianas e f?ngicas, necessitando de mais estudos a fim de identificar as subst?ncias respons?veis por tais atividades e pela citotoxicidade e, valid?-las atrav?s de outros modelos in vitro e in vivo.
Disserta??o (Mestrado) ? Programa de P?s-gradua??o em Ci?ncias Farmac?uticas, Universidade Federal dos Vales do Jequitinhonha e Mucuri, [2016].
Plants are a potencial source of biologically active substances and they are used for therapeutic purposes since the beginning of human civilization. Brazil, in turn, holds a vast biological diversity and has a lot of plant species with medicinal potential. Among the various biomes of Brazil, the Cerrado is the second largest, registering many medicinal species. Consequently, it is necessary to invest more in research of medicinal plants as possible new treatments, especially for the degenerative and chronic disease such as Chagas, Leishmaniasis, cancer and infections caused by bacteria and fungi, whereof treatment has big limitations. The objective of this study was the phytochemical screening and biological activities studies of ethanolic extracts of 12 plants species from the Cerrado, collected in the municipality of Diamantina, Vale do Jequitinhonha / MG.For the preliminary phytochemical screening were made chromogenic and precipitation reactions and analysis in thin-layer chromatography. Cytotoxicity for normal mammalian cells was evaluated in mouse fibroblasts (L929) and the cell line of breast cancer MDA-MB-231 was used to analyze the antitumor activity of the extracts. The evaluation of antitripanossomatideo activity was performed using epimastigotas of Colombiana Trypanosoma cruzi strain and promastigotes of BH46 Leishmania (Leishmania) infantum strain and M2269 Leishmania (Leishmania) amazonensis strain. The analyze of these activities were based at the colorimetric MTT technique. The evaluation of antibacterial and antifungal activities was performed by determining the Minimum Inhibitory Concentration (MIC) employing the colorimetric Resazurin technique. Species of bacteria used were Escherichia coli, Proteus mirabilis, Pseudomonas aeruginosa and Staphylococcus aureus. In the antifungal activity were used four species of yeast (Candida albicans, Candida famata, Candida krusei and Candida tropicalis) and two species of filamentous fungi (Aspergillus niger and Penicillium expansum). Of the 13 extracts evaluated for cytotoxicity using the L929 strain mouse fibroblasts, all they had some cytotoxicity level. Some of these extractsthen showed a high toxicity in this assay cell line, wherein the ethanolic extract of E. erythropappus leaves was the most toxic. In the evaluation of antitumor activity all extracts showed activity, exception for the extract of P. rigida leaves. Among these the most promising was either the ethanolic extract of the leaves of E. erythropappus. Evaluation of trypanocidal activity using Colombian strain of T. cruzi epimastigotas, present active for nine extracts against this parasite, been the A. aculeata and leaves E. erythropappus leaf extract the most promising. Leishmanicidal activity for the M2269 strain of E. erythropappus B. oxyclada leaf extract presented as the most promising and, for the BH46 strain the T. catahartica role plant extract shows the best results, followed by the E. erythropappus leaf extract. In the antibacterial activity assay only the B. oxyclada, P. tomentosa and S. rugosa leaf extracts were active, and the only for P. aeruginosa and S. aureus. Among these the P. tomentosa extract inhibited a greater number of bacteria with bactericidal action. Filamentous fungus A. niger and P. expansum were resistant to all extracts evaluated and C. krusei was the most sensitive yeast. P. tomentosa and B. oxyclada leaf extracts inhibited more yeast species but with the lowest MIC values. Due these results, it is suggested that the E. erythropappus of P. tomentosa and B. oxyclada leaf ethanolic extracts showed the greatest of biological activities, making these the most promising species as potential sources of bioactive molecules for the treatment of cancer, Chagas disease, Leishmaniasis and bacterial and fungal infections, yet requiring further studies to identify the substances responsible for such activities and cytotoxicity and validate them through other models in vitro and in vivo.

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Yagi, Sakina. "Etudes phytochimique et biologique de plantes soudanaises : Hydnora johannis Beccari (Hydnoraceae) et Citrullus lanatus (Thunb.) Matsum. et Nakai var. citroides (Bailey) Mansf. (Cucurbitaceae)." Thesis, Nancy 1, 2011. http://www.theses.fr/2011NAN10138.

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Différents extraits ont été préparés à partir de racines de H. johannis et différents tests biologiques ont été appliqués en vue de rechercher différentes activités. L'extrait aqueux s'est montré particulièrement actif sur Enterococcus fecalis, Staphylococcus aureus et Bacillus. Les extraits aqueux dépourvus de tanins et les tanins isolés ne présentent pas d'activité antibactérienne. L'effet synergétique des composés serait donc responsable de l'activité antibactérienne de la plante. Une activité antifongique sur Microsporum canis, une propriété antiradicalaire et une activité antiglycation ont été constatées avec les deux extraits. Une étude toxicologique de la poudre de plante et de l'extrait éthanolique sur des rats révèle une toxicité au niveau du foie et de la rate. Cinq composés ont été isolés puis identifiés. Il s'agit de 3',4',5-Trihydroxy-6,7-diméthoxyflavone ; 3,5-Dihydroxy-4,7-diméthoxy dihydroflavonol, Catéchine, Vanilline et l'acide Protocatechuic. Du stigmastérol, de l'acide oléique, de l'acide myristique et de l'acide palmitique ont été également identifiés. Le travail sur C. lanatus var. citroides a montré que l'extrait méthanolique (70%) des pulpes de fruits possède une activité contre B. subtilis, S. aureus et E. coli. Les extraits butanolique et à l'acétate d'éthyle ne sont pas toxiques contre les larves de crevettes. L'extrait butanolique possède une propriété significative antiradicalaire. Deux composés ont été isolés et identifiés. Ce sont la Cucurbitacine E 2-O-[bêta]-glucopyranoside et la Cucurbitacine L 2-O-[bêta]-glucopyranoside. Ces composés montrent une activité antibacterienne contre E. coli. La Cucurbitacine L 2-O-[bêta]-glucopyranoside possède une activité antibactérienne contre P. aeruginosa et une propriété modérée anti-radicaux libres
Different extracts were prepared from the roots of H. johannis and different biological tests were performed. Water extract exhibited significant activity against Enterococcus fecalis, Staphylococcus aureus and Bacillus. Water extract devoid from tannin or the tannin fraction did not show any antibacterial activity reflecting the synergistic property of active compounds. Both extracts showed antifungal, antiradical capacity as well as antiglycation activity. Toxicological study of the powder and ethanol extract on rats showed toxicity to the liver and kidney tissues. Five compounds were isolated namely; 3,4,5- Trihydroxy- 6,7-dimethoxy flavone ; 3,5-Dihydroxy- 4,7- dimethoxy dihydroflavonol, Catechin, Vanillin and Protocatechuic acid. Stigmasterol, Oleic acid, Myristic acid and Palmitic acid were also identified. A study on the fruit pulps of C. lanatus var. citroides revealed that the methanolic extract displayed an antibacterial activity against B. subtilis, S. aureus and E. coli. The butanolic extract showed antiradical capacity and was not toxic to brine shrimps larvae. Two compounds were isolated namely; Cucurbitacine E 2-O-[bêta]-glucopyranoside and Cucurbitacine L 2-O- [bêta] -glucopyranoside. Both compounds showed antibacterial activity against E.coli whereas, Cucurbitacine L 2-O-[bêta]-glucopyranoside showed antibacterial activity against P. aeruginosa as well as antiradical activity

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Costa, Helen Paula Silva da. "PurificaÃÃo e caracterizaÃÃo de um inibidor de tripsina com atividade antimicrobiana da torta de pinhÃo-manso (Jatropha curcas L.)." Universidade Federal do CearÃ, 2012. http://www.teses.ufc.br/tde_busca/arquivo.php?codArquivo=7773.

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CoordenaÃÃo de AperfeiÃoamento de Pessoal de NÃvel Superior
Conselho Nacional de Desenvolvimento CientÃfico e TecnolÃgico
O resÃduo (torta) obtido apÃs a extraÃÃo de Ãleo das sementes de pinhÃo-manso (Jatropha curcas) para a produÃÃo de biodiesel Ã tÃxico. Apesar dos entraves relacionados Ã sua utilizaÃÃo na alimentaÃÃo animal, existem evidÃncias de que esse resÃduo tem grande potencial de utilizaÃÃo biotecnolÃgica graÃas ao arsenal de molÃculas que o constitui. Assim, o presente trabalho teve como foco a purificaÃÃo e caracterizaÃÃo de um inibidor de tripsina da torta de pinhÃo-manso, vislumbrando um maior aproveitamento desse resÃduo. A anÃlise da composiÃÃo centesimal revelou ser a torta de pinhÃo-manso composta principalmente por proteÃnas (37,21%), fibras (34,26%) e lipÃdios (19,16%). O extrato bruto obtido a partir da torta sob condiÃÃo alcalina (tampÃo borato de sÃdio 100 mM, pH 10,0) mostrou a presenÃa de lectina (319,76 UH/gF), inibidor de papaÃna (1.287,38 UI/gF), protease (2,69 UA/gF) e, principalmente, de inibidor de tripsina (1.649,7 UI/gF). O inibidor de tripsina, denominado JcTI, foi purificado do extrato bruto por fracionamento com Ãcido tricloroacÃtico (2,5%) seguido de cromatografias de afinidade (tripsina-sepharose-4B) e de exclusÃo molecular (sephacryl S-200). JcTI Ã uma glicoproteÃna (6,4% de carboidratos) com massa molecular na faixa de 20-21 kDa, pI de 6,6, sequÃncia NH2-terminal (VRDICKKEAERQDLSSCENYITQRRGY) exibindo similaridade em torno de 60% com albuminas vegetais e altamente estÃvel ao calor, salinidade e pH. JcTI (500 Âg/mL) retardou o crescimento de vÃrios fungos fitopatogÃnicos de importÃncia agrÃcola, incluindo Colletotrichum gloeosporioides, Colletotrichum lindemuthianum, Fusarium oxysporum e Fusarium solani. Esse inibidor tambÃm mostrou atividade antibacteriana frente a bactÃrias patogÃnicas ao homem, tais como Bacillus subtilis, Salmonella choleraesuis e Staphylococcus aureus, com concentraÃÃo inibitÃria mÃnima inferior a 5 Âg/mL. Os resultados obtidos demonstram o potencial do JcTI para aplicaÃÃo biotecnolÃgica como uma nova proteÃna de defesa contra fungos fitopatogÃnicos e bactÃrias patogÃnicas ao homem.
The residue (cake) obtained after the extraction of oil from jatropha (Jatropha curcas) seeds for biodiesel production is toxic. Despite of the obstacles related to its use in the animal feed, there are evidences that this residue has great potential for biotechnology applications due to its arsenal of molecules. Thus, the present study aimed to purify and characterize a trypsin inhibitor from jatropha cake, in order to make a better use of this residue. The centesimal composition analysis showed to be the jatropha cake mainly composed of proteins (37.21%), fiber (34.26%) and lipids (19.16%). The crude extract obtained from the jatropha cake under alkaline condition (100 mM sodium borate buffer, pH 10.0) showed the presence of lectin (319.76 HU/gF), papain inhibitor (1,287.38 IU/gF), protease (2.69 AU/gF) and, especially, trypsin inhibitor (1,649.7 IU/gF). The trypsin inhibitor, named JcTI, was purified by fractionation of the crude extract with trichloroacetic acid (2.5%) followed by affinity chromatography (trypsin-sepharose-4B) and molecular exclusion (sephacryl S-200). JcTI is a glycoprotein (6.4% carbohydrates) with molecular mass in the range of 20-21 kDa, pI of 6.6, NH2-terminal sequence (VRDICKKEAERQDLSSCENYITQRRGY) showing identity around 60% with plant albumins and highly stable to heat, pH and salinity. JcTI (500 Âg/mL) slowed the growth of important phytopthogenic fungi, including Colletotrichum gloeosporioides, Colletotrichum lindemuthianum, Fusarium oxysporum and Fusarium solani. This inhibitor also presented antibacterial activity against human pathogenic bacteria such as Bacillus subtilis, Salmonella choleraesuis and Staphylococcus aureus, with minimum inhibitory concentration less than 5 Âg/mL. The results demonstrate the potential of JcTI for biotechnological application as a new defense protein against phytopthogenic fungi and human pathogenic bacteria.

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Mathekga, Abbey Danny Matome. "Antimicrobial activity of Helichrysum species and the isolation of a new phloroglucinol from Helichrysum caespititium." Diss., Pretoria : [s.n.], 2001. http://upetd.up.ac.za/thesis/available/etd-04012003-141811.

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Ribeiro, Martins Xavier Nuno Manuel. "Synthesis of new sugar derivatives containing an α,β -unsaturated carbonyl system in their structure and biological evaluation." Thesis, Lyon, INSA, 2011. http://www.theses.fr/2011ISAL0023.

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Ce travail de doctorat porte sur la synthèse et utilisation de bicyclolactones glycidiques, de façon à accéder des dérivés de sucres contenant un système carbonylé α,β-insaturé. Trois types de bicyclolactones ont été étudiés: butenolides liés à des cycles furanose, butenolides fusionnés à des cycles pyranose, comprenant S- et NH-analogues et carboxyméthyle glycosides lactones (CMGLs). La méthodologie de synthèse de butenolides sur motif sucre est basée sur l’oléfination de Wittig de 3 ou 5-cétosucres et lactonisation intramoléculaire spontanée de gamma-hydroxyesters α,β-insaturés intermédiaires. Pour la synthèse des systèmes fusionnés, des furano-3-uloses protégés ont été convertis en 3-C-(éthoxycarbonyl)méthylène furanoses. Une hydrolyse acide finale permet la transestérification intramoléculaire et aussi l’isomérization du cycle en forme pyranose. Des précurseurs 5-S et 5-aminofuranosidiques ont conduit à des analogues thiosucres ou à des dérivés glycidiques ayant une fonction amide et un système carbonylé α,β-insaturé, respectivement. Les CMGLs ont été converties en 3-enopyranosid-2-uloses par l’ouverture de la lactone avec une amine et oxydation/élimination du 2-hydroxy pyranoside tri-O-acétylé obtenu. L’oléfination de Wittig subséquente a conduit aux diènes conjugués pyranosidiques ramifiés en C-2. Les glycosides contenant un groupement propargyle ont permis de préparer des 1,2,3-triazoles par ‘click’ chemistry. Quelques molécules ont été soumises à évaluation antimicrobienne et les énulosides de (N-dodécylcarbamoyl)méthyle ont montré les meilleures activités. Le composé le plus actif est l’énuloside-α qui a montré un très fort effet contre des espèces de Bacillus et une forte activité contre Enterococcus faecalis et Penicillium aurantiogriseum. Les diènepyranosides ont révélé une activité forte et sélective contre E. faecalis. Les dérivés triazolés n'ont montré aucune activité. Parmi les composés bioactifs, trois sont avérés peu toxiques chez les cellules eucaryotes
This PhD work was focused on the synthesis and the uses of carbohydrate bicyclic lactones for the access to sugar derivatives comprising an alpha, beta-unsaturated carbonyl function. Three types of bicyclic lactones were investigated: furanose C-C-Iinked butenolides, pyranose-fused butenolides, including S-or NH-analogues and carboxymethyl glycoside lactones (CMGLs). The synthetic methodology for butenolide containing-sugars was based on the Wittig olefination of 3- or 5-keto sugars and spontaneous intramolecular lactonization of the intermediate gamma-hydroxy axy alpha,beta-unsaturated esters. In the case of the fused systems, protected furanos-3-uloses were converted into 3-C-(ethoxycarbonyl)methylene furanoses. Further acid hydrolysis elicited both intramolecular transesterification and isomerization to the pyranose ring. Introduction of a sulfur or a nitrogen function at C-5 of the furanose precursors led to thiosugar analogues or to carbohydrate derivatives comprising both an amide function and an alpha,beta-unsaturated system, respectively. CMGLs were converted into 3-enopyranosid-2-uloses by a sequence involving opening of the lactone moiety by amines and oxidation/elimination of the resulting tri-0-acetylated 2-hydroxy pyranosides. Further Wittig olefination afforded 2-C-branched-chain conjugated dienepyranosides. Glycosides bearing a propargyl moiety were engaged in "click" chemistry reactions leading to 1,2,3-triazoles. Some of the new molecules were submitted to antimicrobial evaluation and (N-dodecylcarbamoyl)methyl enulosides proved to display the best efficacy. The most active one was the a-enuloside which showed very strong effect towards Bacillus species and strong activity against Enterococcus faecalis and the fungal pathogen Penicillium aurantiogriseum. Dienepyranosides exhibited a strong activity selectively towards E. faecalis. Triazole derivatives were virtually ineffective. Three of the bioactive compounds showed low acute toxicity in eukaryotic cells

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ANGRI, MATTEO. "FOOD SAFETY AND QUALITY IN DEVELOPING COUNTRIES: THE ROLE OF LACTIC ACID BACTERIA." Doctoral thesis, Università Cattolica del Sacro Cuore, 2016. http://hdl.handle.net/10280/10797.

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La sicurezza e la qualità degli alimenti sono tutt’ora un problema critico per i paesi in via di sviluppo. Le diete a basso contenuto di acido folico, per esempio, possono causare gravi problemi di salute, soprattutto nei bambini. Gravi disturbi legati al tubo neurale (DTN) nei neonati possono derivare infatti da madri che hanno insufficiente apporto di acido folico (400-600 g / giorno) durante il periodo di gravidanza. Inoltre, se non adeguatamente protetti o trattati, I prodotti alimentari possono essere vettori di funghi e batteri patogeni rappresentando una fonte potenziale di malattie per l’uomo e una perdita economica per le industrie agro-alimentari. Nella seguente tesi si è quindi quindi studiato il ruolo di batteri lattici selezionati (LAB) in grado di aumentare il valore nutrizionale del latte attraverso la produzione di acido folico durante il processo di fermentazione. Inoltre, ci si è concentrati sul loro uso come "bio-conservanti" contro funghi e batteri, attraverso la sintesi di composti antimicrobici (batteriocine) in grado di inibire la crescita di funghi filamentosi e/o batteri patogeni.
The safety and quality of food are still a critical issue in developing countries. Diets with a low content of folic acid, for example, may cause serious health problems, especially in children. Severe disorders related to neural tube (NTD) in infants may arise from mothers having inadequate intakes of folic acid (400-600 g/dia) during the mother pregnancy period. Moreover foods, when not properly protected or treated, can be vectors of pathogenic fungi and bacteria thereby representing a potential source of human diseases and an economical loss for the food industry. In the following thesis we have therefore investigated the role of selected lactic acid bacteria (LAB) in increasing the nutritional value of milk through the production of folic acid during the fermentation process. In addition, we focused on their use as “bio-preservatives” against fungal and bacterial spoilage, through the synthesis of antimicrobial compounds (bacteriocins) able to inhibit the growth of filamentous fungi and /or pathogenic bacteria.

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Oliveira, Karen Kelly Carvalho de. "Atividade antimicrobiana de basidiomicetos ocorrentes na Amazônia." Universidade Federal do Amazonas, 2014. http://tede.ufam.edu.br/handle/tede/4285.

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Made available in DSpace on 2015-07-07T19:11:17Z (GMT). No. of bitstreams: 1 Dissertação - Karen Kelly Carvalho de Oliveira.pdf: 2064619 bytes, checksum: 99e96187d8cd6db44d7bb15b47d1bbe8 (MD5) Previous issue date: 2014-05-29
FAPEAM - Fundação de Amparo à Pesquisa do Estado do Amazonas
The increase in microbial resistance to available antibiotics and the continuous decrease observed in the number of the new antimicrobial agents approved by Food and Drug Administration creates a constant search for new compounds. To do so, one of the strategies to be followed consists in exploring understudied natural sources, as often organisms obtained new ecosystems are associated with new chemical diversity. In this context are the basidiomycetes, which have been reported as promising sources of antimicrobial and, despite this potential and great biological diversity, the species found in the Amazon have been insufficiently studied. The objective of this study was to evaluate the antimicrobial activity of eight basidiomycetes isolated from Manaus and Boa Vista. The fungi were grown in two liquid media (malt and GLP) and malt-agar medium, in the latter case were held in two incubation conditions: absence and presence of light. The fungi were maintained at room temperature in all treatments. The tests used the filtered liquid from the growth medium for seven to 63 days, besides extracts with ethyl acetate from growing on solid media (ten days). The pathogens tested were Escherichia coli CBAM 001, Staphylococcus aureus CBAM 324, Candida albicans CFAM 1342, Aspergillus niger CFAM 161 and Penicillium sp. CFAM 059, by agar diffusion method. The filtered with positive activity, were submitted to microdilution test for identification of minimum inhibitory concentration. Molecular identification was performed by amplification and sequencing of the rDNA fragment, with subsequent comparison of the sequences obtained with those deposited in the National Center for Biotechnology Information database. Of filtered tested, seven inhibited the growth of C. albicans CFAM 1342, all of Oudemansiella canarii 1528 cultivation, as medium malt, as in GLP. At medium malt, this basidiomycete produced antifungal compounds at seven and 49 days of cultivation, while in the medium GLP produced from the 21 days of cultivation, until the 49th day. The minimum inhibitory concentration was found for the filtrate obtained after 28 days of GLP cultivation medium (2.5 mg/ml) and the filtrate obtained after 49 days malt medium (5 mg/ml). The extracts obtained with ethyl acetate inhibited C. albicans CFAM 1342, Penicillium sp. CFAM 059, E. coli CBAM 001 and S. aureus CBAM 324. This method was found more satisfactory results, as well as Oudemansiella canarii 1528, six other basidiomycetes (Basidiomycete 347, Pleurotus sp. 474, Gloeophyllum sp. 1153, Trametes sp. 1232, Trametes sp. 1540 e Earliella scabrosa 1552) showed antimicrobial activity. Thus, the results allow to observe the influence of culture conditions for the production of antimicrobial compounds, as well as choice of solvents, further studies are needed to determine the optimum conditions for production and extraction thereof.
O aumento da resistência microbiana aos antibióticos disponíveis e o decréscimo contínuo observado no número de novos antimicrobianos aprovados pela Food and Drug Administration gera uma constante busca por novos compostos. Para tanto, uma das estratégias a ser seguida consiste na exploração de fontes naturais pouco estudadas, pois frequentemente organismos obtidos de novos ecossistemas estão associados à nova diversidade química. Neste contexto destacam-se os basidiomicetos, que vêm sendo relatados como promissoras fontes de antimicrobianos e, apesar deste potencial e da grande diversidade biológica, as espécies ocorrentes na Amazônia têm sido pouco estudadas. Assim, o objetivo deste trabalho foi avaliar a atividade antimicrobiana de oito basidiomicetos isolados de Manaus e Boa Vista. Os fungos foram cultivados em dois meios líquidos (malte e GLP) e em meio ágar-malte, neste último caso foram mantidos em duas condições de incubação: ausência e presença de luz. Em todos os tratamentos os fungos foram mantidos em temperatura ambiente. Os testes utilizaram os filtrados provenientes do crescimento em meio líquido de sete a 63 dias, além de extratos obtidos com acetato de etila a partir do cultivo em meio sólido (dez dias). Os patógenos testados foram Escherichia coli CBAM 001, Staphylococcus aureus CBAM 324, Candida albicans CFAM 1342, Aspergillus niger CFAM 161 e Penicillium sp. CFAM 059, através do método de difusão em ágar. Os filtrados com atividade positiva foram submetidos a teste de microdiluição para identificação da concentração inibitória mínima. Foi realizada a identificação molecular através de amplificação e sequenciamento do fragmento do rDNA, com posterior comparação das sequências obtidas com as depositadas no banco de dados do National Center for Biotechnology Information. Dos filtrados testados, sete inibiram o crescimento de C. albicans CFAM 1342, todos provenientes do cultivo de Oudemansiella canarii 1528, tanto em meio malte, como em meio GLP. Em meio malte, este basidiomiceto produziu compostos antifúngicos aos sete e 49 dias de cultivo, enquanto em meio GLP produziu a partir dos 21 dias de cultivo, até o 49º dia. A concentração inibitória mínima foi identificada para o filtrado obtido aos 28 dias de cultivo em meio GLP (2,5 mg/mL) e o filtrado obtido aos 49 dias em meio malte (5 mg/mL). Os extratos obtidos com acetato de etila além de inibir C. albicans CFAM 1342, inibiram Penicillium sp. CFAM 059, E. coli CBAM 001 e S. aureus CBAM 324. Esta metodologia apresentou resultados mais satisfatórios, pois além de Oudemansiella canarii 1528, outros seis basidiomicetos (Basidiomycete 347, Pleurotus sp. 474, Gloeophyllum sp. 1153, Trametes sp. 1232, Trametes sp. 1540 e Earliella scabrosa 1552) apresentaram atividade antimicrobiana. Deste modo, os resultados obtidos permitiram observar a influência das condições de cultivo para a produção de compostos antimicrobianos, assim como a escolha de solventes, sendo necessários estudos posteriores para determinar a melhor condição para a produção e extração destes compostos.

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15

Martins, Táric Ramon Marques. "Síntese, caracterização e avaliação da atividade biológica de ligantes orgânicos da classe das tiossemicarbazonas, semicarbazonas e hidrazonas." Universidade Federal de Goiás, 2017. http://repositorio.bc.ufg.br/tede/handle/tede/7762.

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Fundação de Amparo à Pesquisa do Estado de Goiás - FAPEG
The drugs have had a great positive impact on humanity, contributing directly to the prevention of diseases, and increased quality and expectancy of life. However, with widespread use among the population, several microorganisms have become resistant to marketed drugs, being necessary to discover new formulations and substances effective against the main mechanisms of resistance. The classes of compounds called semicarbazones (SCs) and thiosemicarbazones (TSCs) have received great attention from the researchers. This is due to its pharmacological activities, such as antibacterial activity. Thus the objective of this work was to synthesize new organic compounds, to characterize them spectroscopically and structurally, and to perform biological tests against pathogens. Two hydrazones, one semicarbazone and one thiosemicarbazone were synthesized and characterized. Biological tests with the four compounds for evaluation of antibacterial and antifungal activity determined the Minimum Inhibitory Concentration (MIC). The compound N-methyl-2- [1,1,1-trifluoro-4-oxo-4- (thiophen-2-yl) butan-2-ylidene] hydrazine carbothioamide (compound 1) showed antibacterial activity against Gram negative Serratia marcescens (MIC 64 μg/mL) and Gram positive bacteria Enterococcus faecalis (MIC 64 μg/mL). The compound (2Z)-2-[1,1,1-trifluoro-4-oxo-4-(thiophen-2-yl) butan-2-ylidene] hydrazine carboxamide (compound 4) showed antibacterial and antifungal activity with the minimum inhibitory concentration between 32 μg/mL and 256 μg/mL.
Os medicamentos trouxeram um grande impacto positivo sobre a humanidade; contribuindo diretamente para a prevenção de doenças, contribuindo para qualidade e aumento da expectativa de vida. No entanto com o uso amplamente difundido entre a população, vários microrganismos tem adquirido resistência aos medicamentos comercializados, sendo necessário a descoberta de novas formulações e substancias efetivas contra os principais mecanismos de resistência. As classes de compostos denominadas semicarbazonas (SCs) e tiossemicarbazonas (TSCs) vêm recebendo grande atenção dos pesquisadores. Esse fato se deve as suas atividades farmacológicas, como por exemplo a atividade antibacteriana. Dessa forma o objetivo deste trabalho foi sintetizar novos compostos orgânicos, caracterizar espectroscopicamente e estruturalmente, e realizar testes biológicos frente a agentes patogênicos. Foram sintetizadas e caracterizadas duas hidrazonas, uma semicarbazona e uma tiossemicarbazona. Os testes biológicos com os quatro compostos para avaliação da atividade antibacteriana e antifúngica, determinaram a Concentração inibitória mínima (MIC). O composto N-methyl-2- [1,1,1-trifluoro-4-oxo-4- (thiophen-2-yl) butan-2-ylidene] hydrazine carbothioamide (composto 1) apresentou atividade antibacteriana contra a bactéria Gram negativa Serratia marcescens (MIC 64 μg/mL) e a bactéria Gram positiva Enterococcus faecalis (MIC 64 μg/mL). O composto (2Z)-2-[1,1,1-trifluoro-4-oxo-4-(thiophen-2-yl)butan-2-ylidene] hydrazinecarboxamide (composto 4) apresentou atividade antibacteriana e antifúngica com a concentração inibitória mínima entre 32 μg/mL a 256 μg/mL.

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Joaquim, Angélica Rocha. "Síntese de derivados de 8-hidroxiquinolina e avaliação da atividade antimicrobiana." reponame:Biblioteca Digital de Teses e Dissertações da UFRGS, 2018. http://hdl.handle.net/10183/181465.

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A prospecção e síntese de novos derivados de 8-hidroxiquinolina está em ascensão devido às suas diversas atividades biológicas. Neste trabalho é relatada a síntese e avaliação da atividade antimicrobiana de novos derivados contendo uma sulfonamida substituída na posição 5 da 8-hidroxiquinolina ou um grupamento aminossubstituído na posição 7 da 5-cloro-8-hidroxiquinolina ou 5-cloro-8-metoxiquinolina. Os derivados 5-sulfonamidas foram preparados por clorossulfonação seguida da reação com a amina apropriada. Os derivados 7-aminossubstituído foram sintetizados através da metilação da hidroxila da posição 8, seguida da reação de cross-coupling catalisada por paládio e desmetilação. A avaliação da atividade antimicrobiana foi realizada através do método de microdiluição em caldo. Dentre os compostos sintetizados, 5a (da série 5-sulfonamidas) foi o mais potente, sendo ativo contra todas as espécies fúngicas testadas, além de apresentar importante atividade contra cepas de Staphylococcus aureus, e baixa toxicidade contra células VERO. Isso sugere que a introdução de um grupamento retirador de elétrons em para no substituinte arila da posição 5 é importante para a atividade antimicrobiana. Ainda, a nanoemulsão preparada contendo 5a manteve a atividade antifúngica da substância contra espécies de Candida spp. A série 7-aminossubstituído também apresentou resultados muito interessantes. Desta série, o composto 5i foi o mais potente. Isso sugere que grupamentos heterocíclicos hidrofílicos na posição 7 podem favorecer a atividade antifúngica. A presença da hidroxila livre na posição 8 parece ser essencial para a atividade antifúngica, pois os derivados protegidos por uma metila foram pouco ativos. Os derivados de 8-hidroxiquinolina 5a e 5i podem ser considerados para estudos posteriores na busca de novos agentes antimicrobianos.
The synthesis and screening of new 8-hydroxyquinoline derivatives is growing, due to their various biological activities. In this work, the synthesis and antimicrobial evaluation of new derivatives containing a substituted 5-sulfonamide in the 8-hydroxyquinoline or a substituted amino group at the 7-position of the 5-chloro-8-hydroxyquinoline or 5-chloro-8-methoxyquinoline is reported. The 5-sulfonamide derivatives were prepared by chlorosulfonation followed by the reaction with the appropriate amine. The 7-amino derivatives were synthesized by methylation of the 8-hydroxyquinoline, followed by palladium-catalyzed cross-coupling reaction and demethylation. The antimicrobial evaluation was tested by the broth microdilution method. Among all the prepared compounds, 5a (from the 5-sulfonamide series) was the most potent, being active against all the fungal species tested, while also showing important activity against Staphylococcus aureus strains, and low toxicity against VERO cells. This suggests that the introduction of an electron-withdrawing group at para-position of the N-aryl substituent is important for the activity. In addition, the prepared 5a nanoemulsion maintained the antifungal activity of the compound against Candida spp. The 7-amino series has also presented interesting results. In this series, 5i was the most potent compound. This suggests that the hydrophilic heterocyclic substituent at the 7-position was favorable to antifungal activity. The presence of the free hydroxyl at the 8-position is important for the antifungal activity, since the methyl-protected derivatives were poorly active. The 8-hydroxyquinoline derivatives 5a and 5i may be considered for further studies in the search for novel antimicrobial agents.

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17

CUNHA, Marcelo Holanda da. "Composição química e atividade biológica do extrato hidroalcoolico de própolis preta." Universidade Federal de Campina Grande, 2018. http://dspace.sti.ufcg.edu.br:8080/jspui/handle/riufcg/880.

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Neste trabalho buscou-se investigar a composição química, o efeito antifúngico e antibacteriano do extrato da própolis preta, in vitro, em leveduras do gênero Candida e bactérias do grupo Staphylococcus aureus, respectivamente. A princípio obteve-se as amostras de 06 (seis) espécies de Candida spp. e 01(uma) de Sthaphylococus aureus por doação. Assim como, a própolis proveniente da jurema preta, cedida pelo apiário Edimel. A própolis preta foi extraída e sua composição química foi caracterizada por Cromatografia Líquida de Alta Eficiência. Posteriormente, os extratos hidroalcoolicos da própolis preta foram elaborados por dois métodos, a saber: maceração a quente e Soxhlet, com o intuito de se obervar a melhor forma de obter a melhor síntese e seu rendimento do referido extrato. Em seguida, as leveduras do gênero Candida sp foram reidratadas e semeadas, enquanto que a bactéria Sthaphylococus aureus foi replicada. As amostras viáveis foram testadas quanto ao perfil de sensibilidade considerando-o como sensível, sensibilidade dose-dependente e resistente utilizando como método de referência o teste de difusão em disco, de acordo com os documentos M44-A2 e M2-A8 do Clinical and Laboratory Standards Institute, respectivamente. Os resultados evidenciaram que o perfil químico da própolis preta consta de 14 substâncias químicas, e dentre elas, destacam-se as maiores concentrações para o ácido 3,4-dihidroxibenzoico (14,19 mg/mL), a rutina (12,71 mg/mL), o ácido transcinâmico (6,25 mg/mL), sendo esses responsáveis por atividade antioxidante e antibacteriana. Os processos de extração hidroalcoólica da própolis por maceração a quente e por soxhlet, resultaram respectivamente, em 43,6% e 57,6% de rendimento. Sugerindo que a extração por soxhlet apresentou melhor viabilidade, em virtude de redução de tempo e aumento na temperatura frente à maceração a quente. No que concerne, a reidratação e semeaduras das culturas de leveduras do gênero Candida sp, 100% das amostras apresentaram crescimento satisfatório para o desenvolvimento dos testes de sensibilidade. No entanto, o extrato hidroalcoólico de própolis preta testado nas concentrações de 26,4 mg/mL (33%), 52,8 mg/mL (66%) e 79,2 mg/mL (99%) e do álcool etílico a 70%, todos frente ao crescimento das 06 (seis) espécies de Candida, que se observaram ser resistentes ao extrato, enquanto para o fluconazol na concentração de 25 mg/mL, marcador antifúngico, foram sensíveis. Já, para o teste de difusão em disco com o extrato hidroalcoólico de própolis preta testado nas concentrações de 26,4 mg/mL (33%), 52,8 mg/mL (66%) e 79,2 mg/mL (99%), bem como do cloranfenicol na concentração de 30 mg/mL e do álcool etílico a 70%, frente ao crescimento da espécie de Staphylococcus aureus, estes apresentaram sensibilidades frente ao marcador antibacteriano e aos extratos. A formação dos halos por S. Aureus, indicando a sensibilidade tanto para os extratos hidroalcoólicos da própolis preta, cujos diâmetros foram entre 19 a 25,3 mm, e no marcador (Cloranfenicol) com diâmetro entre 30 a 30,1 mm. Em suma, pode ser afirmado que a própolis preta apresentou atividade antibacteriana para bactérias da espécie Staphyloccocus aureus, não havendo atividade antifúngica frente as leveduras do gênero cândida. Efeito esse relacionado à presença de compostos fenólicos e flavonóides, e que a predominância da concentração desses compostos bioativos, influencia na ação biológica dos microorganismos, estudados neste trabalho, Candida sp e Staphylococus aureus, em virtude de ter apresentado inibição e sensibilidade, respectivamente para esses microorganismos.
We studied the chemical composition of the black propolis extract, and its in vitro antifungal and antibacterial effects against yeasts of the genus Candida spp. (six species) and the bacterium Staphylococcus aureus. The propolis from Mimosa hostilis (Jurema-preta) flowers was provided by the Edimel apiary. Black propolis was extracted, and its chemical composition was measured by High-Performance Liquid Chromatography. Hydroalcoholic extracts of black propolis were done through two methods, hot maceration and Soxhlet, to obtain the best synthesis and yield. The yeasts were rehydrated and sown, whereas the bacterium was replicated. Viable samples were tested for sensitivity profile and classified as: sensitive, dose-dependent, and resistant. For the disc diffusion test, we followed reference methods described in the M44-A2 and M2-A8 documents of the Clinical and Laboratory Standards Institute, respectively for Candida spp. and S. aureus. The chemical profile of black propolis comprises 14 chemical substances. The compounds with highest concentrations were: protocatechuic acid (14.19 mg/mL), rutin (12.71 mg/mL), and transcinnamic acid (6.25 mg/mL), which were responsible for the antioxidant and antibacterial activity. The hydroalcoholic extraction processes of propolis by hot maceration and Soxhlet resulted in yields of 43.6% and 57.6%, respectively. Thus, the Soxhlet extraction showed better viability due to its faster extraction and increase in temperature. After rehydration and sowing, all samples of yeast cultures showed satisfactory growth for the sensitivity tests. All Candida species were resistant to the extract of black propolis (at the concentrations of 26.4 mg/mL – 33%; 52.8 mg/mL – 66%; and 79.2 mg/mL – 99%), and to 70% ethanol, whereas they were sensitive to fluconazole at 25 mg/mL, the antifungal marker. The S. aureus was sensitive to the extracts at all concentrations and to chloramphenicol at 30 mg/mL, the antibacterial marker. The halos around the discs show the sensitivity of S. aureus to both hydroalcoholic extracts of black propolis, whose diameters ranged from 19 to 25.3 mm, while the marker halos ranged from 30 to 30.1 mm. So, the black propolis showed antibacterial activity against S. aureus but no antifungal activity against Candida spp. The antibacterial activity occurred due to the presence of phenolic and flavonoid compounds. The predominance of these bioactive compounds affects the biological activity of microorganisms.

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18

Nate, Zondi. "Green synthesis of copper and silver nanoparticles and their antimicrobial activity." Thesis, Vaal University of Technology, 2018. http://hdl.handle.net/10352/424.

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M. Tech. (Department of Chemistry, Faculty of Applied and Computer Sciences), Vaal University of Technology
The present study includes the use of a green synthetic method to prepare copper and silver nanoparticles using chitosan, aqueous extracts of Camellia sinensis, Combretum molle and Melia azedarach linn leaves. This study aims to investigate the influence of capping and precursor concentration on the properties of silver nanoparticles with emphasis on the medicinal plants chosen. The effect of capping agent on the properties of copper nanoparticles is also investigated. The phytochemical properties of plant extracts and the antimicrobial activity of the synthesized particles were also studied; this was achieved by using microdilution bioassay. Decoction method was used to extract secondary metabolites from plant leaves. Preliminary phytochemical screening carried out on the aqueous extracts of the plant leaves showed the presence of tannins, proteins, flavonoids, phenols, and carbohydrates. The total phenolic and flavonoids content of the aqueous extract was determined using spectroscopic methods. The highest phenolic content was found in the aqueous extract of Combretum molle (135 mg/g), and the highest flavonoid content was found in the aqueous extract of Camellia sinensis (0.4 mg/g). Characterization was done by a combination of spectroscopic, microscopy and XRD techniques. Both the size and shape of the synthesized silver nanoparticles were dependent on the identity of the capping molecule, precursor and capping agent concentration as depicted from their TEM and XRD results. Silver nanoparticles were found to be predominantly spherical. The capping agent concentration was also found to influence the degree of agglomeration, with an increase in capping agent concentration giving lesser agglomeration. FTIR spectral analysis showed that silver nanoparticles interact with bioactive compounds found in the plants through the hydroxyl functional group. Other shapes including diamond were observed for the effect of precursor concentration. The XRD micrographs revealed a face-centered cubic geometry and the phase remained the same with an increase in precursor concentration. The synthesized silver nanoparticles were all blue shifted compared to the bulk material. The TEM results revealed that copper nanoparticles with different sizes and shapes were successfully synthesized. All the prepared copper and silver nanoparticles showed satisfactory antifungal and antibacterial activity against Candida albicans, Cryptococcus neoformans, Staphylococcus aureus, Enterococcus faecalis, Klebsiella pneumonia and Pseudomonas aeruginosa. The capping molecules used in this study also showed some antibacterial and antifungal activity against the selected strains. However nanoparticles performed better than these capping molecules. Both silver and copper nanoparticles were found to be more active against gram-negative bacteria compared to gram-positive bacteria. Amongst all the prepared silver nanoparticles Combretum molle capped nanoparticles were found to be the most active nanoparticles. Also with copper nanoparticles, it was found that Combretum molle capped nanoparticles were the most active nanoparticles. Between the two metal nanoparticles, silver nanoparticles showed high antibacterial and antifungal activity compared to copper nanoparticles. The antioxidant activity of silver nanoparticles was assessed using 2.2-diphenyl-1-picrylhydrazyl. Silver nanoparticles were found to have some antioxidant activity. However, the capping molecules were found to be more active than the synthesized nanoparticles. This observation is attributed to the presence of some bioactive compounds in the plant extracts.

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Costa, Helen Paula Silva da. "Purificação e caracterização de um inibidor de tripsina com atividade antimicrobiana da torta de pinhão-manso (Jatropha curcas L.)." reponame:Repositório Institucional da UFC, 2012. http://www.repositorio.ufc.br/handle/riufc/16947.

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COSTA, Helen Paula Silva da. Purificação e caracterização de um inibidor de tripsina com atividade antimicrobiana da torta de pinhão-manso (Jatropha curcas L.). 118 f. : Dissertação (Mestrado) - Universidade Federal do Ceará, Centro de Ciências, Departamento de Bioquímica e Biologia Molecular, Programa de Pós-Graduação em Bioquímica. Fortaleza-CE, 2012.
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The residue (cake) obtained after the extraction of oil from jatropha (Jatropha curcas) seeds for biodiesel production is toxic. Despite of the obstacles related to its use in the animal feed, there are evidences that this residue has great potential for biotechnology applications due to its arsenal of molecules. Thus, the present study aimed to purify and characterize a trypsin inhibitor from jatropha cake, in order to make a better use of this residue. The centesimal composition analysis showed to be the jatropha cake mainly composed of proteins (37.21%), fiber (34.26%) and lipids (19.16%). The crude extract obtained from the jatropha cake under alkaline condition (100 mM sodium borate buffer, pH 10.0) showed the presence of lectin (319.76 HU/gF), papain inhibitor (1,287.38 IU/gF), protease (2.69 AU/gF) and, especially, trypsin inhibitor (1,649.7 IU/gF). The trypsin inhibitor, named JcTI, was purified by fractionation of the crude extract with trichloroacetic acid (2.5%) followed by affinity chromatography (trypsin-sepharose-4B) and molecular exclusion (sephacryl S-200). JcTI is a glycoprotein (6.4% carbohydrates) with molecular mass in the range of 20-21 kDa, pI of 6.6, NH2-terminal sequence (VRDICKKEAERQDLSSCENYITQRRGY) showing identity around 60% with plant albumins and highly stable to heat, pH and salinity. JcTI (500 µg/mL) slowed the growth of important phytopthogenic fungi, including Colletotrichum gloeosporioides, Colletotrichum lindemuthianum, Fusarium oxysporum and Fusarium solani. This inhibitor also presented antibacterial activity against human pathogenic bacteria such as Bacillus subtilis, Salmonella choleraesuis and Staphylococcus aureus, with minimum inhibitory concentration less than 5 µg/mL. The results demonstrate the potential of JcTI for biotechnological application as a new defense protein against phytopthogenic fungi and human pathogenic bacteria.
O resíduo (torta) obtido após a extração de óleo das sementes de pinhão-manso (Jatropha curcas) para a produção de biodiesel é tóxico. Apesar dos entraves relacionados à sua utilização na alimentação animal, existem evidências de que esse resíduo tem grande potencial de utilização biotecnológica graças ao arsenal de moléculas que o constitui. Assim, o presente trabalho teve como foco a purificação e caracterização de um inibidor de tripsina da torta de pinhão-manso, vislumbrando um maior aproveitamento desse resíduo. A análise da composição centesimal revelou ser a torta de pinhão-manso composta principalmente por proteínas (37,21%), fibras (34,26%) e lipídios (19,16%). O extrato bruto obtido a partir da torta sob condição alcalina (tampão borato de sódio 100 mM, pH 10,0) mostrou a presença de lectina (319,76 UH/gF), inibidor de papaína (1.287,38 UI/gF), protease (2,69 UA/gF) e, principalmente, de inibidor de tripsina (1.649,7 UI/gF). O inibidor de tripsina, denominado JcTI, foi purificado do extrato bruto por fracionamento com ácido tricloroacético (2,5%) seguido de cromatografias de afinidade (tripsina-sepharose-4B) e de exclusão molecular (sephacryl S-200). JcTI é uma glicoproteína (6,4% de carboidratos) com massa molecular na faixa de 20-21 kDa, pI de 6,6, sequência NH2-terminal (VRDICKKEAERQDLSSCENYITQRRGY) exibindo similaridade em torno de 60% com albuminas vegetais e altamente estável ao calor, salinidade e pH. JcTI (500 µg/mL) retardou o crescimento de vários fungos fitopatogênicos de importância agrícola, incluindo Colletotrichum gloeosporioides, Colletotrichum lindemuthianum, Fusarium oxysporum e Fusarium solani. Esse inibidor também mostrou atividade antibacteriana frente a bactérias patogênicas ao homem, tais como Bacillus subtilis, Salmonella choleraesuis e Staphylococcus aureus, com concentração inibitória mínima inferior a 5 µg/mL. Os resultados obtidos demonstram o potencial do JcTI para aplicação biotecnológica como uma nova proteína de defesa contra fungos fitopatogênicos e bactérias patogênicas ao homem.

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Dascalu, Anca-Elena. "Bioantibio, biosourced antibacterial and antifungal molecules." Thesis, Lille, 2019. http://www.theses.fr/2019LILUS052.

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Le manque d'innovations thérapeutiques a récemment atteint un niveau critique par rapport aux traitements antibiotiques. Cette question, corrélée à l’apparition de bactéries multirésistantes, a mis en évidence la nécessité de nouvelles approches pour la découverte d’antibiotiques innovants. En conséquence, le projet BIOANTIBIO a été proposé.Les deux principales applications initialement envisagées pour les composés les plus actifs sont:• Additifs pour la formulation de matériaux innovants (par exemple, peintures et revêtements) afin de garantir leur durabilité en stockage (en collaboration avec IFMAS).• Médicaments : agents antibactériens et antifongiques, en particulier pour le développement d’agents antimicrobiens contre les bactéries résistantes aux médicaments, destinés à la protection de la santé humaine.L'utilisation de molécules naturelles pour développer de nouvelles classes d'antifongiques ou d'antimicrobiens peut être difficile. Néanmoins, on sait que la nature inspire les chimistes dans la synthèse de molécules aux propriétés biologiques et dans le cadre de ce projet, nous avons démontré que même l’acide pyroglutamique, composé biosourcé bien connu, devait encore être exploité en tant que motif phare de la chimie du laboratoire
The lack of therapeutic innovations has recently reached a critical level, considering antibiotic treatments. This issue, correlated with the appearance of multidrug-resistant bacteria underlined the need for new approaches towards the discovery of innovative antibiotics. As a consequence, the BIOANTIBIO project was proposed.The two main initially envisioned applications for the most active compounds being:• Additives for the formulation of innovative materials (eg paints and coatings) in order to guarantee their durability in storage (working in collaboration with IFMAS).• Drugs: antibacterial and antifungal agents, particularly for the development of antimicrobial agents against drug-resistant bacteria for human health protection.Employing natural molecules to develop novel antifungal or antimicrobial classes can be challenging. Nevertheless, nature is known to inspire chemists in the synthesis of molecules with improved biological properties and within this project we have demonstrated that even the well known pyroglutamic acid is still to be exploited as a scaffold

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Franche, Antoine. "Amphiphiles azobenzéniques : potentiel et relations structure-activité pour la lyse cellulaire." Thesis, Compiègne, 2019. http://www.theses.fr/2019COMP2523.

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L’émergence de souches bactériennes et fongiques de plus en plus résistantes à la désinfection est un problème qui menace le développement et la santé humaine à travers le monde. Parmi les modes d’action possibles de ces traitements, notre intérêt va se porter sur les interactions avec la membrane plasmique dans le but de lyser le micro-organisme. Le premier objectif de cette thèse est donc de développer des molécules avec une structure amphiphile afin d’interagir avec ces membranes. Les azobenzènes sont intéressants à ce titre car leurs deux groupements phényles constituent déjà un squelette carboné apolaire. Le greffage d’une tête polaire sur ces molécules permettra donc de leur conférer des propriétés amphiphiles. Trois familles d’azobenzènes ont été synthétisées afin d’évaluer leurs propriétés antibactériennes et antifongiques. Un autre objectif de la thèse est de fournir les premières hypothèses sur le mode d’action des antibactériens synthétisés. Plus particulièrement, leur capacité à interagir avec des membranes plasmiques biomimétiques de bactéries a été évaluée. La première famille (AzoOH) comportant un groupement hydroxyle comme tête polaire a montré de bonnes propriétés biologiques mais une faible capacité à interagir avec les membranes plasmiques. La seconde famille (AzoPEG), avec une tête polaire de type triéthylène glycol a montré de médiocres activités biologiques, et une capacité à interagir avec les membranes plasmiques n’ont pas été améliorées. La troisième famille (AzoTAI) avec une tête polaire de type triméthylammonium a montré d’excellentes propriétés biologiques, une capacité à s’adsorber aux interfaces hydrophiles/hydrophobes et une interaction spécifique avec les lipides membranaires bactériens. L’interaction entre les AzoTAI à plus longue chaîne (6 carbones) et la phosphatidylethanolamine est particulièrement favorable. De manière globale, parmi les composés synthétisés, seule la famille des AzoTAI est capable d’interagir avec la membrane plasmique des bactéries et cette interaction est corrélée à l’activité antibactérienne. Néanmoins, même si ces composés constituent de bons candidats pour la lyse des microorganismes, leur activité cytotoxique vis-à-vis des cellules humaines pourrait limiter leurs applications dans le domaine médical
The emergence of bacterial and fungal strains more and more resistant to disinfection is a threat to the development of nations and human health around the world. Amongst the mechanism of action, we will focus on the interaction between the molecule and the plasmic membrane for the lysis of the microorganism. The first goal of this work is to synthetize amphiphilic molecules to interact with bacterial membrane Azobenzene are interesting because their two phenyl group give them an apolar moiety, the next step is a grafting of a polar head to make them become an amphiphile molecule. Three types of azobenzene were synthetized to evaluate their antibacterial properties and their antifungal properties. The second goal of this work is tounderstand how they interact with the plasmic membranes. To perform this, we tested the azobenzenes on biomimetic models of plasmic membranes. The first group of compounds (AzoOH) with an alcohol group as polar head showed good biological properties but have a poor potential to interact with plasmic membrane. The second group of compounds (AzoPEG) with a triethylene-glycol type polar head have mediocre biological activities, and their ability to interact with the membrane were not enhanced. The third group of compounds (AzoTAI) with a trimethylammonium type polar head showed very good biological activities, and strong interaction with bacterial membrane lipid. These antibacterial activities are correlated to their interaction with bacterial lipids. It also has good abilities to adsorb themselves to hydrophilic/hydrophobic interfaces. However, their cytotoxic activity on human cells can be a severe drawback with their use

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Coventry, Emma. "Antibacterial and antifungal properties of neem (Azadirachta indica A. Juss)." Thesis, University of Aberdeen, 1997. http://digitool.abdn.ac.uk/R?func=search-advanced-go&find_code1=WSN&request1=AAIU100079.

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A number of commercial neem pest control products and a laboratory prepared seed water extract were screened for antibacterial activity against bacteria with different Gram staining reactions, morphologies and pathogenicity using the agar diffusion technique. The neem component of the Trifolio-M GmbH commercial products, termed "active ingredient", and the unformulated product, MIDECOL-CF, exhibited antibacterial activity against Gram-positive and -negative bacteria including phytopathogens. The formulations of the Trifolio-M GmbH products were themselves shown to possess considerable antimicrobial activity. A Thin Layer Chromatography (TLC0 bioassay was developed using Bacillus mycoides to detect antibacterial metabolites in separated neem extracts. Three discrete zones of growth inhibition were obtained with the active ingredient indicating the presence of at least three antibacterial metabolites. TLC bioassay of laboratory prepared seed and leaf extracts resulted in considerable inhibition of B. mycoides which could not be attributed to one metabolite. No antibacterial activity was detected in pure samples of azadirachtin, nimbin or salannin. Neem callus of Ghanaian and Nigerian origin was fractionated using solid phase extraction and analysed using High Performance Liquid Chromatography (HPLC) and TLC. Both calli exhibited antibacterial activity against B. mycoides in more than one fraction although activity differed between fractions and the calli of different origins. The effect of the active ingredient on the growth of four fungal phytopathogens was investigated. Mycelial growth of Gaeumannomyces graminis var. tritic was completely inhibited in vitro although control could not be achieved in planta. Mycelial growth of Microdochium nivale was significantly reduced in vitro in the presence of the active ingredient. This extract had little effect on mycelial growth of Botrytis cinerea although MIDECOL-CF was shown to inhibit conidial germination. Activity was however lost when MIDECOL-CF was separated using TLC suggesting the presence of metabolites which act synergistically. The active ingredient inhibited conidial germination of Sphaerotheca fuliginea in vitro although no control was achieved in planta.

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Dorla, Emmanuelle. "Étude phytochimique et propriétés bioactives de Peperomia borbonensis (Miq.) Piperaceae." Thesis, La Réunion, 2016. http://www.theses.fr/2016LARE0027.

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Les maladies impliquant des micro-organismes représentent un problème majeur de santé publique en raison du fort taux de mortalité provoqué par l'accroissement et l'émergence de souches résistantes. De même, les régions tropicales du Monde et La Réunion doivent faire face depuis plusieurs années à la pression accrue d'arthropodes ravageurs de cultures et vecteurs de maladies. Pour lutter contre ces arthropodes, les pesticides synthétiques aux conséquences désastreuses sur l'Homme et l'environnement sont principalement utilisés. Depuis quelques années, on observe un phénomène grandissant de résistance aux molécules conventionnelles à la fois chez les micro-organismes et les arthropodes. Face à ce constat, il est primordial de proposer de nouvelles molécules bioactives capables de lutter efficacement contre les ravageurs et les micro-organismes. Dans ce cadre, un criblage préliminaire réalisé sur vingt plantes endémiques et indigènes de La Réunion a permis de mettre en évidence l'activité antibactérienne et acaricide des extraits acétate d'éthyle de plusieurs espèces végétales. En raison de son large spectre d'activités biologiques, Peperomia borbonensis Miq. (Piperaceae), a été sélectionnée pour une investigation chimique et biologique approfondie. La suite de nos travaux a été consacrée à l'isolement et la caractérisation des métabolites secondaires de l'extrait apolaire de cette espèce. Les fractionnements bio-guidés réalisés ont conduit à l'isolement de quatorze molécules dont un amide à la structure nouvelle. Par ailleurs, l'étude de la fraction volatile de cette espèce a montré le potentiel insecticide de l'huile essentielle des feuilles pour lutter contre la mouche du melon B. cucurbitae
The emergence of resistant strains in infectious diseases is a major public health issue. Similarly, arthropods which caused important economic damages in tropical and subtropical areas are continuously developing resistance to chemicals. To counteract this situation, it is essential to find new bioactive molecules able to fight pests and micro-organisms. In this context a preliminary screening was performed on twenty endemic plants and native of Reunion. Twenty-six ethyl acetate extracts were tested for their antibacterial and acaricidal activities. Considering its broad spectrum of activity, Peperomia borbonensis Miq. (Piperaceae), was selected for further chemical and biological investigations. Two bio-guided fractionations were performed on its apolar extract and let to the isolation of fourteen molecules. Moreover, the study of the volatile fraction has shown the insecticidal potential of the leaf essential oil of P. borbonensis against the melon fly B. cucurbitae

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Magnusson, Jesper. "Antifungal activity of lactic acid bacteria /." Uppsala : Dept. of Microbiology, Swedish Univ. of Agricultural Sciences, 2003. http://epsilon.slu.se/a397.pdf.

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Davey, Ronald William. "The antibacterial activity of propolis." Thesis, Imperial College London, 1998. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.286314.

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Henriques, Ana. "The antibacterial activity of honey." Thesis, Cardiff Metropolitan University, 2006. http://hdl.handle.net/10369/839.

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Honey is an old remedy recently rediscovered as a possible alternative to modern antibiotics in wound management but its mode of action is not fully understood. The antibacterial activity of honey can be divided into hydrogen peroxide and non-hydrogen peroxide-derived activity. This later type of activity is characteristic of honeys from Australasia (e.g. manuka honey) and preferred for wound management, although historically local honeys have been used. The main aim of this study was to investigate the mechanisms of antibacterial action of manuka honey. The stability of antibacterial action of manuka honey under different conditions was determined, it was observed that manuka honey lost its antibacterial activity when pH was increased and that it remained the same with heating. Storage seemed to increase the potency of manuka honey. The effects of honey on Staph. aureus and Pseud. aeruginosa, were investigated using MIC/MBC detenninations, time-kill studies, commitment to death, resistance training, electron microscopy, effects on respiration rates, leakage of intracellular material, and for Staph. aureus the proteome of treated and non-treated cells were compared. It was observed that the effect of manuka honey on Gram-positive and Gram-negative cells is different. Gram-positive bacteria had a lower MIC than Gram-negative bacteria, but the time-kill experiments and the commitment-to-deaths howed that Gram negative were inhibited more rapidly. Clinical strains of both bacteria showed different time-kill profiles to type strains. The methodology used for MIC determination was found to affect to the results obtained. No honey-resistant ram-positive bacteria were recovered, but Gramnegative bacteria were found to be able to become phenotypically resistant to manuka honey. Electron microscopy showed that honey inflicted physical damages in both types of cells, and in Gram-positive bacteria led to an increase in the proportion of population of cells with a complete septum. Gram-positive cells incubated in honey increased their endogenousre spiration rate whilst this was decreased in Gram-negative, major leakage was observed in Gram-negative bacteria whilst only minor leakage was observed in Gram-positive bacteria, which is consistent with the amount of damage observed with electron microscopy. The proteome analysis of Staph aureus, revealed a general down regulation of protein synthesis. Thirty Portuguese honeys were assayed for their antibacteriaal ativity and honeys derived from Lavandulas toechas(lavender) were found to possess non-peroxide activity. A selection of manuka honeys was screened for antimicrobial producing bacteria. In total 106 bacteria were recovered (85% were identified as Bacillus sp. ) and of those, 76 were capable of inhibiting the growth of at least one strain of bacteria tested, meaning that some of the antibacterial activity in manuka honey could be due to the presence of antimicrobial agents of bacterial origin. The antibacterial activity of manuka honey has previously been claimed to be due to hydrogen peroxide production and not to a non-peroxide source of activity. A study of free radical production and antioxidant potential demonstrated that manuka honey did not produce any hydroxyl radicals via the Fenton reaction. Thus hydrogen peroxide could not be present. It was also observed that even free radical-producing honeys were able to quench radical production in vitro. In conclusion this study has demonstrated that the non-peroxide activity of manuka honey is not exclusive to Australasia honeys, that it is not derived from hydrogen peroxide generation and may have a microbial origin. Furthermore the action of manuka honey on Gram-negative bacteria seems to be more physical than in Gram positive where it appears to interfere with the cell physiology, perhaps by stopping the cell cycle before cytokinesis.

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Dorman, Hugh Jude Damien. "Phytochemistry and bioactive properties of plant volatile oils : antibacterial, antifungal and antioxidant activities." Thesis, University of Strathclyde, 1999. http://oleg.lib.strath.ac.uk:80/R/?func=dbin-jump-full&object_id=21318.

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Aromatic and medicinal plants have been recognized since antiquity as possessing biological activities; chief amongst these are their antibacterial, antifungal and antioxidant properties. In this study, the chemical composition, the antimicrobial and in vitro antioxidant bioactivities the volatile oils extracted by hydrodistillation from aromatic and medicinal members of the plant families Geraniaceae: geranium (Pelargonium graveolens L'Herit); Lamiaceae: melissa (Melissa officinalis L.), monarda (Monarda citriodora var. citriodora Cerv. ex Lag.), oregano (Origanum vulgare ssp. hirtum (Link) Letsw.) and thyme (Thymus vulgaris L.); Myristicaceae: nutmeg (Myristica fragrans Houtt.); Myrtaceae: clove (Syzygium caryophyllus Gaertn.); Piperaceae: black pepper (Piper nigrum L.) and Umbelliferae: lovage (Levisticum officinalis L.) were investigated. The chemical percentage composition of the volatile oils extracted from black pepper, clove, geranium, lovage (from both leaf and stem material), melissa, monarda, nutmeg, oregano and thyme were analysed using gas chromatography and mass spectroscopy. The findings of these analyses confirmed that volatile oils from aromatic and medicinal members of different plant families are principally mixtures of mono- and sesqui- terpenoids compounds. Furthermore, oil samples extracted from species of the same plant family, samples sourced from different parts of the same plant and a commercial and authenticated volatile oil described as from the same species may exhibit different compositions, i.e. the percentage composition and variation in individual phytochemicals. A series of experiments were carried out in an attempt at assessing the antibacterial properties of black pepper, clove, geranium, melissa, nutmeg, oregano and thyme volatile oils and their main components. A collection of 25 test microorganisms [9 Gram-positive and 16 Gram-negative strains] including human, plant and veterinary pathogens and food spoilage organisms. All the volatile oils demonstrated some degree of antiseptic activity with the oils of oregano and thyme being particularly active. The phenyipropanoid eugenol and the phenolic constituents carvacrol and thymol were found to be strongly antiseptic. The antifungal activity of black pepper, clove, melissa, oregano and thyme volatile oils against the agriculturally important Aspergillus species Aspergillus flavus (Link) Fries and Aspergillus niger van Tieghen, and the Fusarium species Fusarium culmorum W.G. Smith was investigated. All the volatile oil samples demonstrated antifungal properties with variable degrees of efficacy across the concentration levels used in this study, with the volatile oils of oregano and thyme being particularly inhibitory. The in vitro antioxidant properties of the volatile oils of black pepper, clove, nutmeg, oregano and thyme and their major components were evaluated by using a method routinely used in this laboratory, a simplified plate diffusion technique for determining lipid antioxidant activity using linoleic acid/β-carotene. To investigate further the potential antioxidant activity of these plant extracts and their main components and characterise their underpinning mechanism of action, an attempt to develop and optimize current antioxidant screening techniques was carried out. These methods included a thiobarbituric reactive species assay, a conjugated diene assay and a free-radical trapping assay. Finally, a series of feeding trials were carried out to assess whether volatile oils feed at various concentrations prior to and during pregnancy can beneficially affect the compositional levels of major fatty acids in a maternal and foetal/neonatal model extracted from cholesteryl ester, triacylglyceride, free fatty acid and phosphoglyceride lipid fractions in an organ dependent manner. Particular focus centered upon the saturated fatty acids lauric, palmitic and stearic acids; the essential fatty acids[LA](18:2n-6) and α-linoleic [LA] (18:2n-6) and α-linolenic [ALA (18:3n-3) acids and the long chain polyunsaturated fatty acid metabolic derivatives, e.g. arachidonic acid [ARA] (20:4n-6), docosahexaenoic [DHA] (22:6n-3) and eicosapentnoic acid [EPA] (20:5n-3). The volatile oil of oregano was administered orally to female rats at 167mg Kgˉ¹; 334 mg Kgˉ¹ and 843 mg Kgˉ¹ concentration levels immediately prior to and during pregnancy to determine whether they affected the fatty acids composition in a variety of major maternal and neonatal organs. In addition to the aforementioned experiment, further feeding trails were carried out using the volatile oils of clove and nutmeg at a 5Oµg gˉ¹ concentration level.

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Hansen, Bruce Richard. "Antifungal activity of some New Zealand fungal isolates." Thesis, University of Canterbury. Plant and Microbial Sciences, 1998. http://hdl.handle.net/10092/6849.

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The secondary metabolism of organisms, especially mycelial fungi, is attracting increasing attention since it may produce a reservoir of unique molecules from which therapeutic agents are formed or derived for clinical application The production of secondary metabolites is not well understood and involves a broad spectrum of metabolic processes that often have little in common. This study screened a number of New Zealand isolates, mostly of the Arthrinium genus, and assessed their antifungal activity. The primary screening used for this study consisted of agar diffusion tests with a range of filamentous fungi and yeast. Secondary screening was also started, with active cultures being chemically extracted. It was found that New Zealand isolates of Arthrinium phaeospermum display antifungal activity against yeasts and filamentous fungi, as well as bacteria. The teleomorphic state of an Arthrinium sp., Apiospora montagnei, was found to have activity against the yeast S. cerevisiae. In addition, activity against two filamentous fungi by Apiospora montagnei was demonstrated. In the course of this study, a contaminant fungus displaying antifungal activity was isolated and screened. It was found to have antifungal activity against C. albicans and filamentous fungi, as well as bacteria.

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Fewell, Alison. "Interactive antifungal activity between co-occurring Solanum glycoalkaloids." Thesis, University of Exeter, 1993. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.359158.

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de, Beer Irving. "Screening of plant-mediated nanoparticles for antifungal activity." University of the Western Cape, 2020. http://hdl.handle.net/11394/7955.

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>Magister Scientiae - MSc
Nanotechnology is spreading rapidly across the world as an extremely powerful technology. Nanoscience and nanotechnology are innovative scientific advancements that have been introduced only in this century. Nanotechnology has developed as the scientific advancement to grow and transform the entire agri-food area, with the potential to elevate global food production, in addition to the nutritional value, quality, and safety of food and food products. It has gained recognition due to its variability in shape, size, and dimension and how it correlates to its possibilities. One of those functions is nanoparticles’ (NPs) ability to have antimicrobial activity, more specifically its antifungal activity. One particular pathway of synthesising NPs is through phytonanotechnology which is the use of biomaterial to synthesis the NPs.
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Al-Sagher, Mohamed Ramadan. "Antibacterial activity of galactoside analogues of biocides." Thesis, University of Nottingham, 1992. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.315112.

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Pereira, Joana Brás. "Synthesis and antibacterial activity of cationic phthalocyanines." Master's thesis, Universidade de Aveiro, 2012. http://hdl.handle.net/10773/8999.

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Mestrado em Biologia Molecular e Celular
Antimicrobial photodynamic therapy (aPDT) was described more than 100 years ago, but its potential as an alternative to combating microorganisms, was only recognized when antibiotic resistance became an important public health issue. aPDT refers to the action of 3 non-toxic elements: a photosensitizer, light and molecular oxygen that, when combined, results in the production of singlet oxygen (1O2) and/or free radicals which are cytotoxic to target cells. The aim of this work was to synthetize, evaluate and compare the photoinactivation efficiency of new cationic phthalocyanines (Pcs) derivatives. Three new derivatives, tetra and octa-thio-pyridinium Pcs, 17, 18 and 19, were tested against Gram-negative bacteria. A recombinant bioluminescent Escherichia coli strain was used to assess, in real time, the photoinactivation efficiency of these cationic Pcs, under white and red light. After a pre-incubation period with 20 μmol L-1 of PS in the dark, the pure bacterial suspensions were irradiated with white light (400-800 nm) or red light (620- 750 nm) at a fluence rate of 150 mW cm-2, for 30 minutes. Dark and light controls were performed in all experiments. The cellular localization, uptake, 1O2, photophysical and photochemical tests such as photostability, solubility and fluorescence quantum yields were also determined, in order to evaluate the potential of these new Pcs as antibacterial agents. Pc 18 was the most effective photosensitizer, causing a 5 logs reduction in bioluminescence after 30 minutes of irradiation under white or red lights. The photoinactivation efficiency of the Pc 19 was similar (5 logs reduction in bioluminescence) to that of 18 when irradiated with white light, but the efficiency of inactivation was reduced (2.1 logs reduction in bioluminescence) under red light. Pc 17 was the least effective PS, causing only 2.1 log bioluminescence reduction under white light and 1 log decrease under red light. The three new cationic thio-pyridinium phthalocyanines with different physicochemical properties have different photoinactivation efficiencies to inactivate a gram negative bacterium. Several factors such as aggregation, 1O2 generation, number of thio-pyridinium groups, cellular uptake/localization and irradiation conditions could cause the different efficiency observed. The high photodynamic efficiency of compound 18 under red light is of special interest for clinical applications, since red light is the most preferable for treatment of microbial infections, because it penetrates deeper into infected human tissues.
A terapia fotodinâmica antimicrobiana (aPDT) foi descrita pela primeira vez há mais de 100 anos, mas o seu potencial como alternativa no combate de microrganismos apenas foi reconhecido devido à resistência a antibióticos, que se revelou um grave problema de saúde pública. aPDT refere-se à acção de três componentes não tóxicos: um fotossensibilizador (PS), uma fonte de luz e oxigénio molecular que, em conjunto, levam à geração de oxigénio singuleto (1O2) e/ou radicais livres, que são citotóxicos para as células alvo. O objectivo deste trabalho foi sintetizar, avaliar e comparar a eficiência da fotoinativação de novos derivados catiónicos de ftalocianinas (Pcs). Três novos derivados, ftalocianinas tetra e octa-tio-piridil, 17, 18 e 19, foram testadas numa bactéria Gram-negativa. Foi utilizada uma estirpe de Escherichia coli recombinante bioluminescente para determinar, em tempo real, a eficácia da fotoinativação das ftalocianinas catiónicas, sob luz branca e luz vermelha. Após um período de préincubação no escuro com 20 μmol L-1de PS, as suspensões bacterianas puras foram irradiadas com luz branca (400-800 nm) ou luz vermelha (620-750 nm) sob 150 mW cm-2, durante 30 minutos. Foram realizados em todos os ensaios controlos claro (irradiação da suspensão bacteriana sem PS) e escuro (suspensão bacteriana com PS, sem irradiação). Foram também determinados a localização subcelular, uptake, 1O2, testes fotofísicos e fotoquímicos tal como a fotoestabilidade, solubilidade e determinação do rendimento quântico de fluorescência para avaliar o potencial das novas ftalocianinas como agentes antibacterianos. O derivado 18 foi o PS mais eficiente, causando uma redução de 5 logs na bioluminescência após 30 minutos de irradiação com luz branca ou com luz vermelha. A fotoinativação provocada pela Pc 19 foi semelhante (5 logs de decréscimo na bioluminescência) à da 18, quando irradiada com luz branca, mas a eficiência da inactivação reduziu (2.1 logs decréscimo na bioluminescência) sob luz vermelha. A Pc 17 foi o PS menos eficiente, causando apenas 2.1 logs de decréscimo na bioluminescência sob luz branca e diminuição de 1 log sob luz vermelha. As três novas ftalocianinas tio-piridil com diferentes propriedades físico-químicas, revelam uma eficiência diferente na fotoinativação de uma bactéria Gram-negativa. Vários factores tais como agregação, geração de 1O2, número de grupos tio-piridil, bem como as condições de irradiação, uptake /localização celular podem estar na causa das diferenças verificadas na fotoinativação. A elevada eficiência fotodinâmica do composto 18 na presença da luz vermelha é de especial interesse para aplicações clínicas, uma vez que a luz vermelha é a mais adequada para o tratamento de infecções microbianas, pois penetra mais profundamente em tecidos humanos infectados.

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33

Ta, Chieu Anh Kim. "Bacterial Biofilm Inhibition and Antifungal Activity of Neotropical Plants." Thesis, Université d'Ottawa / University of Ottawa, 2015. http://hdl.handle.net/10393/32419.

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This thesis examined the antimicrobial activity of select neotropical plants from Costa Rica and traditional Q’eqchi Maya medicines from Belize. In particular the potential for interference with bacterial quorum sensing (QS) and biofilm formation as well as fungal growth were assessed. Of one hundred and twenty six extracts collected from Costa Rica, one third showed significant QS inhibition while 13 species displayed more biofilm inhibitory activities than the positive control allicin. The active species belonged to the Lepidobotryaceae, Melastomataceae, Meliaceae, Sapindaceae, and Simaroubaceae. Twelve Marcgraviaceae species were tested for the same biological activities; of these, three showed similar QS inhibition to that of the positive control Delisea pulchra (Greville) Montagne and five with at least 30% biofilm inhibition. Only one species inhibited fungal growth – Marcgravia nervosa Triana & Planch. Bioassay-guided isolation of this plant resulted in the identification of the active principle as a naphthoquinone, with a minimum inhibitory concentration (MIC) ranging from 85 to 100 μM against Saccharomyces cerevisiae. Similarly, sixty one Q’eqchi’ Maya medicinal plant species were evaluated for their antimicrobial activities. Of these, four species showed more QS inhibition than D. pulchra, seven with comparable biofilm inhibitory activities that of allicin, and two with similarly antifungal activity to berberine. Two spirostanol saponins were isolated from Cestrum schlechtendahlii G.Don, an active antifungal plant. The major saponin showed growth inhibition against Saccharomyces cerevisiae and Fusarium graminearum, with MICs of 16.5 μM and 132 μM, respectively. Further analyses of this compound using chemical genomics suggested that its antifungal mechanism of action is pleiotropic, affecting multiple targets. Taken together, these findings showed that neotropical plants and traditional Q’eqchi’ Maya medicines contain phytochemicals that interfere with bacterial biofilm formation and quorum sensing as well as fungal growth.

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Albaridi, Najla. "The antibacterial activity of honey against Campylobacter jejuni." Thesis, University of Surrey, 2013. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.616479.

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Honey is a food with high popularity, consumption and availability. The effective antibacterial activity of honey, without any reported bacterial resistance or side effects, increases its use in traditional medicine for treating many different kinds of infections. Initially, this study examined the antibacterial activity of honey against Campylobacter jejuni. Six different types of honey, which were commercially available in the UK, Saudi Arabia and New Zealand, were assessed. Honey samples were introduced to Muller Hinton media in three different ways: filtration, autoclaving honey alone and autoclaving honey with media. C. jejuni NCTC 11168 showed good sensitivity to all six investigated honey samples. The minimum inhibitory concentrations ranged between 2 and 10 % for filtered honey. Thermal treatment increased the activity of some honey types and the MIC was 4% for all honey samples, except for clear honey (C.) Heating honey (2 %, v/v) with the medium resulted in an increase in antibacterial activity with C. jejuni, reducing to detectable levels after 6 hours of incubation. A similar result was observed when honey was mixed with casein, followed by thermal treatment. This result indicates that thermal treatment generates a selection of new antibacterial agents in the honey-casein mixture (honey-casein MRPs).

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35

Cushnie, T. P. Tim. "Investigation of the antibacterial activity of selected flavonoids." Thesis, Robert Gordon University, 2006. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.430050.

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36

Cherrington, Christina Anne. "The antibacterial activity of short-chain organic acids." Thesis, University of Bristol, 1989. http://hdl.handle.net/1983/77ce9cef-1fa2-4387-8b84-f26df3f53717.

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Almeida, Beatriz Luciana Tavares de. "Investigating the antibacterial activity of Pedobacter lusitanus NL19." Master's thesis, Universidade de Aveiro, 2017. http://hdl.handle.net/10773/21523.

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38

Blaxland, James. "The antibacterial activity of Humulus lupulus against mycobacteria." Thesis, Cardiff University, 2015. http://orca.cf.ac.uk/73639/.

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One third of the world’s population is estimated to be infected with M. tuberculosis, a pathogen which causes more human death and misery than any other bacterial disease. Whilst treatment is available, resistance to commonly used antimicrobials is a growing problem. Thus there is an urgent need to identify new compounds that can kill drug resistant isolates and are able to potentiate the activity of currently available antibiotics. The plant kingdom is a rich source of antibacterial compounds and a plant which has attracted particular interest is Humulus lupulus, more commonly known as the hop, which has been used as an antibacterial in beer for hundreds of years. Its antibacterial properties are thought to be due to the combined action of alpha and beta acids and polyphenols such as xanthohumol although the precise nature of their interactions and relative importance has yet to be determined. An optimised agar antimicrobial assay was developed and employed based on Mycobacterium smegmatis, to characterize the antibacterial activity of fifty commercially available hop varieties with a view to identifying novel antibacterial compounds. Surprisingly, no correlation was found between alpha and beta acid content and antibacterial activity. Chemical analysis of the most (Citra) and least (Galena) active hop variants using a combination of bioactivity based thin layer chromatography, mass spectrometry and HPLC revealed differences in the relative amounts of antimicrobial compounds such as humulone (alpha acid), lupulone (beta acid) and xanthohumol but failed to identify the presence of novel antibacterial compounds. Whilst no new antimicrobial compounds were identified, the Citra hop extract was able to potentiate the activity of the antibiotics imipenem and ciprofloxacin against clinical isolates of M. abscessus, a fast growing member of the mycobacterium family which infects individuals suffering from cystic fibrosis. The Citra hop extract also inhibited the growth drug resistant isolates of M. abscessus suggesting that it may have activity against other antibiotic resistant mycobacteria such as M. tuberculosis With regards to the mode of action, scanning electron microscopy revealed distinct changes to the outer cell structure of the bacteria, suggesting that hops contain compounds that interact with the bacterial cell membrane and/or cell wall. These changes were more profound in the presence of sub-inhibitory concentrations of imipenem, a compound which also targets the cell wall. Overall hops were shown to contain compounds which inhibited the growth of mycobacterium and were able to potentate the activity of antibiotics currently used to treat these pathogens. These findings suggest hops may be a fruitful source from which to isolate next generation compounds with which to treat increasingly drug resistant strains of mycobacteria.

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39

Tshanga, Siphokazi Sisanda. "Antibacterial activity of liposome encapsulated cyclo(TYR-PRO)." Thesis, Nelson Mandela Metropolitan University, 2011. http://hdl.handle.net/10948/1450.

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Cyclic dipeptides (CDPs) are amino acid-based compounds, some of which possess antibacterial activity. The encapsulation of certain drugs into liposomes has been found to improve their activity in terms of bioavailability and duration of action. Liposomes are small vesicles that are under investigation as drug carriers for the delivery of therapeutic agents. A number of liposome formulations are currently under clinical trial review, whilst some have already been approved for clinical use. The aim of this study was to optimize a liposomal cyclo(Tyr-Pro) formulation and to assess its antibacterial activity against various Gram-positive and Gram-negative bacteria. Response surface methodology (RSM) using the central composite design (CCD) model was used to optimize liposomal formulations of cyclo(Tyr-Pro) for each of the four bacteria, namely Bacillus cereus, Staphylococcus aureus, Escherichia coli and Pseudomonas aeruginosa. Percent drug encapsulated and bacterial inhibition were investigated with respect to two independent variables, i.e. lipid composition and cholesterol content. Design Expert 8 was used for the purpose of finding the combination of independent variables that would yield an optimal formulation for each bacterium. The model selected by the software failed to adequately correlate the predicted models to the experimental data. The in vitro experiments showed that the antibacterial activity of liposome-encapsulated cyclo(Tyr-Pro) was superior to that of its free counterpart. Binding maximum or Bmax for the encapsulated compound at concentrations as low as 0.412 mg/ml, was significantly higher than that obtained for free cyclo(Tyr-Pro) which was tested at a concentration of 20 mg/ml. Furthermore, encapsulation of cyclo(Tyr-Pro) into a liposome formulation enhanced its potency. This was evident in the lower IC50 values for the liposomal compound when compared to free cyclo(Tyr-Pro).

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Barber, Megan Marie. "2,4-Disubstituted Quinazolines with Antileishmanial or Antibacterial Activity." Scholar Commons, 2015. http://scholarcommons.usf.edu/etd/5840.

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Herein 47 2,4-disubstituted quinazolines were synthesized and tested against Leishmania donovani intracellular amastigotes. A structure-activity relationship was conducted and lead to the identification of quinazolines with EC50s in the single digit and high nanomolar range with favorable antileishmanial selectivity indexes. Quinazoline 2.6 and 2.31 underwent in vivo efficacy studies in murine models of visceral leishmaniasis, reducing liver parasitemia by 12 % and 24 %, respectively, when given by the intraperitoneal route at 15 mg/kg/day x 5 days. The antileishmanial efficacy and easy of synthesis make the 2,4-disubstituted quinazoline compound series a suitable platform for the future development of antileishmanial agents. A similar series of 50 N2,N4-disubstituted quinazoline-2,4-diamines has also been synthesized and tested against multi-drug resistant strains of Acinetobacter baumannii. Quinazolines with MICs in the single digit micromolar range were identified within the structure-activity relationship. The observed potencies of the top compounds and the easy of synthesis lend to the further investigation of in vivo efficacy studies and could be considered a suitable platform for the future development of anti-bacterial agents against A. baumannii.

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41

Elfakhri, S. O. "Antibacterial activity of novel self-disinfecting surface coatings." Thesis, University of Salford, 2014. http://usir.salford.ac.uk/33219/.

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The antibacterial activities of different thin films (TiO2/CuO, Cu/SiO2 and Ag/SiO2) prepared by ﬂame-assisted chemical vapour deposition (FACVD) and atmospheric pressure thermal (APT-FCVD) for TiO2/CuO films, were investigated against standard strains of bacteria used for disinfectant testing and against multi-antibiotic resistant bacteria that have been shown to persist in the hospital environment. These included; MRSA strains (EMRSA15 and two recent clinical isolates MRSA 1595 and MRSA 1669), extended spectrum β-lactamase (ESBL) producing Escherichia coli, a second (ESBL- 2 ) producing Escherichia coli, KPC+ (carbapenemase producing) Klebsiella pneumoniae, Stenotrophomonas maltophilia, Acinetobacter baumannii, Listeria monocytogenes, Salmonella enterica ser typhimurium, and vancomycin resistant Enterococcus faecium (VRE) . The Antimicrobial activity of the above coatings (Cu/SiO2 and Ag/SiO2) was investigated based on the BS ISO 22196:2009 and 2011 Plastics – Measurement of antibacterial activity on plastics and other porous surfaces. The activity of TiO2/CuO films was investigated based on the BS ISO 27447:2009 Test method for antibacterial activity of semiconducting photocatalytic materials. On the TiO2/CuO films, the bacteria were killed by UVA irradiation of the photocatalyst with a >5 log kill within 4-6 h except for the MRSA where a 2.3 log kill was obtained after 6 h increasing to >5 log after 24 h. There was antimicrobial activity in the dark which was enhanced by irradiation with fluorescent light. There was also activity at 5ºC under UVA but activity was lower when fluorescent light was used for illumination. The Cu/SiO2 coating showed a >5 log reduction in viability after 4 h for the disinfectant test strain (E.coli) and for some pathogenic strains include; Acinetobacter baumannii, Klebsiella pneumoniae and Stenotrophomonas maltophilia. However, their activity against the other hospital isolates was slower but still gave a >5 log reduction for extended spectrum β-lactamase producing Escherichia coli and Salmonella enterica typhimurium, and > 2.5 log reduction for vancomycin resistant Enterococcus faecium, Listeria and methicillin resistant Staphylococcus aureus within 24 h. The coating was also active at 5ºC but was slow compared to room temperature. The highest activity of copper /silica films was seen at 35ºC, but bacterial cells were also killed on the control surfaces. The Ag/SiO2 coating was also active against pathogenic bacteria; however the coating was not hard or durable as other coatings used. The activity on natural contamination in an in use test in a toilet facility was also determined for coated ceramic tiles (Cu/SiO2 and Ag/SiO2) and coated steel. The results demonstrated that the tiles were highly active for the first 4 months period and the contamination was reduced by >99.9%. However, tiles lost some of their activity after simulated ageing and washing cycles. The Cu/SiO2 coated ceramic tiles placed in Manchester Royal Infirmary also showed antimicrobial activity and no indicator organisms were detected. The coatings had a good activity against both standard test strains and clinical isolates. The coatings (copper surfaces in particular), may have applications in health care by maintaining a background antimicrobial activity between standard cleaning and disinfection regimes. They may also have applications in other areas where reduction in microbial environmental contamination is important, for example, in the food industry. However, the optimum composition for use needs to be a balance between activity and durability. Keywords: TiO2, CuO, Ag, Antimicrobial; Chemical vapour deposition; Copper; Disinfection surface; Pathogenic bacteria (hospital pathogen).

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42

Yang, Mandy. "An investigation of the antifungal and antitumor activity of ajoene." Thesis, University of Canterbury. Biological sciences, 2013. http://hdl.handle.net/10092/8201.

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The garlic extract ajoene is considered to have antimicrobial and antitumor effects against a variety of cell types, and it is suggested to have the potential to be used as an antifungal or antitumor drug clinically. The underlying mechanism of its inhibitory effects is still uncertain. In this project, the effects of ajoene on the growth of fungal and oomycete cells were studied on Candida albicans, Neurospora crassa and Achlya bisexualis. Endometrial cancer is the most common gynecologic cancer. A 3D spheroid model of endometrial cancer cells were for the first time used to investigate the antitumor effects of ajoene and selected antitumor agents. Ajoene was extracted from fresh garlic by chromatographic methods and the outcome of the extractions was verified with Mass spectrometry and NMR spectroscopy. Ajoene was then tested on the yeast form or germ tubes of C. albicans, and the cell division and germ tube formation was analyzed. N. crassa and A. bisexualis were treated with ajoene on plates or on glass slides to measure the hyphae radial extension or individual hyphal extension. 3D endometrial adenocarcinoma cell (Ishikawa) spheroids were treated with ajoene, paclitaxel, targeted drugs everolimus, sorafenib, gefitinib and canertinib alone or in combinations. The growth activity, metabolic activity, cell proliferation, apoptotic activity and the cytoskeletons were analyzed after the treatments. Cell division of C.albicans was inhibited by ajoene at 5µg/ml or higher concentrations. The length of C.albicans germ tubes was significantly shorter in ajoene treated groups than the untreated ones. Radial extension and individual hyphal extension of N. crassa and A. bisexualis were both inhibited by ajoene. Ajoene did not show any antitumor effects on the 3D cell model of Ishikawa cells. No synergistic effect was detected between ajoene and paclitaxel or ajoene and everolimus. The targeted drugs Canertinib and everolimus showed an inhibitory effect on growth activity of the spheroids, but no synergy with paclitaxel. In conclusion, ajoene was able to inhibit various forms of fungal and oomycete growth, but any antitumor activity of ajoene did not show on 3D culture of endometrial cancer cells.

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43

Thomas, Russell John. "The synthesis of novel #beta#-lactams with potential antifungal activity." Thesis, University of Exeter, 1990. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.277147.

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44

Asmyou, Sana Alhadi. "An in-vitro study of antifungal activity of gymnemic acid." University of the Western Cape, 2017. http://hdl.handle.net/11394/6239.

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Magister Chirurgiae Dentium - MChD (Oral Medicine and Periodontics)
Candida species are frequently isolated from oral mucosal surfaces of healthy individuals and is the most common genus responsible for up to 75% of all candidal infections. The most common problems associated management of oral candidiasis are antifungal drug resistance and side effects Natural medicine is an emerging field and is being explored to overcome drug resistance and to reduce side effects. Gymnemagenin (will be known as Gymnemic acid; GA) is a purified extract from Gymnema sylvestre, a slow growing, perennial, medicinal plant found in Central and Western India, Tropical Africa and Australia is regarded as one of the plants with potent antimicrobial and antifungal activity.

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45

Silva, Maria Zelandia Rocha. "Insulation immunoaffinity chromatography and antifungal activity osmotinas of latex fluid." Universidade Federal do CearÃ, 2015. http://www.teses.ufc.br/tde_busca/arquivo.php?codArquivo=14503.

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CoordenaÃÃo de AperfeÃoamento de Pessoal de NÃvel Superior
Plants are constantly exposed to a variety of stresses conditions. However, they react to biotic stresses by triggering a set of defense mechanisms including the synthesis of defensive substances as the pathogenesis-related (PR) proteins. The PR-protein named osmotin can be induced under osmotic stress and water shortage conditions. Osmotin-like proteins have been purified from latex and some of them are related to antifungal activity. The aim of this study was to investigate the osmotin in the following species laticifers: C. grandiflora, P. rubra, T. peruviana, H. drasticus and C. papaya to isolate and evaluate its antifungal activities. Immunoaffinity column chromatography with anti-CpOsm antibodies were performed in order to purify these osmotin-like. They were detected in latex of C. grandiflora and P. rubra by immunoassays the ELISA, Dot Blot and Western Blot using anti-CpOsm antibody (the osmotin of C. procera latex). Osmotin of C. procera, C. grandiflora, P. rubra and H. drasticus were identified by mass spectrometry. However, the osmotin from C. procera was co-purified with cysteine proteases. The co-purified cysteine protease from C. procera was identified as Procerain B. The alignment and the 3-D structure analysis of Procerain B and CpOsm revealed the presence of a similar sequence in both proteins. This sequence might be an epitope which allows the anti-antibody recognition. The osmotin from C. grandiflora, and P. rubra did not show antifungal activity against Fusarium solani and Colletotrichum gloesporioides. Since no correlation between the antifungal activity and the presence of these osmotins were found, the proteolytic activities of these latex protein fractions were evaluated in order to correlate with the antifungal activity C. procera and C. grandiflora showed a strong proteolytic activity. In latex, the cysteine proteases are more often related to antifungal activity than osmotin, which might explain, at least in part, the antifungal activity performed by C. grandifora and not for its osmotin. Further studies on the role of osmotin in physiology laticifers plants are needed.
As plantas estÃo constantemente sujeitas a diversos tipos de estresse, tanto biÃticos como abiÃticos, resultando em respostas de defesa. Decorrente disto, os vegetais sintetizam certas proteÃnas denominadas de proteÃnas relacionadas Ã patogÃnese (PR proteÃna). As Pr-proteÃnas chamadas de osmotinas podem ser induzidas sob condiÃÃes de estresse osmÃtico, frio e escassez de Ãgua. Osmotinas tem sido purificadas de fluidos laticÃferos e algumas delas estÃo relacionadas com a atividade antifÃngica. O objetivo do presente trabalho foi prospectar osmotinas, bem como isolÃ- las e avaliar suas atividades antifÃngicas, nos fluidos laticÃferos das seguintes espÃcies: C. grandiflora, P. rubra, T. peruviana, H. drasticus e C. papaya. Nos lÃtex de C. grandiflora e P. rubra foram detectadas osmotinas atravÃs de imunoensaios em placa de ELISA, Dot Blot e Westen Blot, utilizando os anticorpos anti-CpOsm (osmotina do lÃtex de C. procera). Cromatografia de imunoafinidade em coluna com anticorpos anti-CpOsm foram realizadas com o intuito de purificar estas osmotinas. AnÃlises por meio de espectrometria de massas, revelaram a presenÃa de osmotina em C. procera, C. grandiflora, P. rubra e H. drasticus. No entanto, a osmotina de C. procera foram co-purificadas com proteases cisteÃnicas. A protease cisteÃnica co- purificada no lÃtex de C. procera foi identificada como Proceraina B. O alinhamento e a anÃlise da estrutura tridimensional da Proceraina B e CpOsm revelaram a presenÃa de uma sequÃncia semelhante em ambas as proteÃnas, que pode ser um epÃtopo disponÃvel ao reconhecimento do anticorpo anti-CpOsm. As osmotinas isoladas de C. grandiflora e P. rubra nÃo apresentaram atividade antifÃngica contra F. solani e C. gloesporioides. Desde que nÃo houve correlaÃÃo entre a atividade antifÃngica e Ã presenÃa destas osmotinas, as atividades proteolÃticas das fraÃÃes proteicas foram avaliadas a fim de correlaciona-las Ã atividade antifÃngica. Nos fluidos laticÃferos, as proteases cisteÃnicas estÃo mais frequentemente relacionadas Ã atividade antifÃngica do que as osmotinas. Estudos mais aprofundados sobre a funÃÃo das osmotinas na fisiologia de plantas laticÃferas sÃo necessÃrios.

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46

Clarke, Annette June Morgan. "The physical characterization and antibacterial activity of herring protamines." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 1998. http://www.collectionscanada.ca/obj/s4/f2/dsk1/tape10/PQDD_0029/MQ47419.pdf.

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47

Stevens, P. J. E. "The antibacterial activity of some analogues of nalidixic acid." Thesis, Brunel University, 1985. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.354567.

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48

Hadjivassileva, Tsveta. "A study of the antibacterial activity of pyrrolobenzodiazepine dimers." Thesis, University College London (University of London), 2006. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.439514.

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49

Molina, Raul Sneyder. "IN VITRO ANTIBACTERIAL ACTIVITY OF 12 COMMERCIAL MOUTHRINSE FORMULATIONS." Master's thesis, Temple University Libraries, 2018. http://cdm16002.contentdm.oclc.org/cdm/ref/collection/p245801coll10/id/489566.

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Oral Biology
M.S.
Objectives: Mouthrinses are widely used by dental patients in daily oral hygiene practices. However, claims of antimicrobial effects are often made by mouthrinse manufacturers without substantiation by laboratory testing on complex oral microbial communities, such as the dorsal tongue microbiota, which are readily exposed in vivo to mouthrinse solutions, and contribute to the etiology of oral halitosis (bad breath). This study employed a modified Kirby-Bauer zone of inhibition test to comparatively examine the in vitro antimicrobial activity of 12 commercial mouthrinse formulations on a mixture of three bacterial species frequently isolated from the human tongue dorsum. Methods: The 12 commercial mouthrinse formulations tested were 1.) Perio-Aid Treatment Mouthwash (Dentaid S.L., Cerdanyola del Vallès, Spain; containing 0.12% chlorhexidine gluconate and 0.05% cetylpyridinium chloride without alcohol), 2.) Paroex (Sunstar Americas, Inc., Schaumburg, IL; containing 0.12% chlorhexidine gluconate without alcohol), 3.) Peridex (3M ESPE Dental Products, St. Paul, MN, USA; containing 0.12% chlorhexidine gluconate plus 11.6% alcohol), 4.) Perio-Aid Maintenance Mouthwash (Dentaid S.L.; containing 0.05% chlorhexidine gluconate and 0.05% cetylpyridinium chloride without alcohol), 5.) Halita Mouthwash for Halitosis (Dentaid S.L.; containing 0.05% chlorhexidine gluconate, 0.05% cetylpyridinium chloride, and 0.14% zinc lactate without alcohol), 6.) Crest Pro-Health Clinical (Procter & Gamble, Cincinnati, OH, USA; containing 0.1% cetylpyridinium chloride without alcohol), 7.) Therasol (formerly from OraTec Corp., Manassas, VA; containing C31G complex of alkyl dimethyl amine oxide and alkyl dimethyl glycine plus 8% alcohol), 8.) Listerine Cool Mint Zero Alcohol (Johnson & Johnson Consumer, Inc., Skillman, NJ, USA; containing essential oils 0.092% eucalyptol, 0.042% menthol, 0.06% methyl salicylate, and 0.064% thymol, without alcohol), 9.) PerioShield Oral Health Rinse (formerly from Sunstar Americas, Inc.; containing 0.2% delmopinol hydrochloride plus 1.5% alcohol), 10.) Listerine Cool Mint (Johnson & Johnson Consumer, Inc.; containing essential oils 0.092% eucalyptol, 0.042% menthol, 0.06% methyl salicylate, and 0.064% thymol, plus 21.6% alcohol), 11.) CloSys Antiseptic Oral Rinse (Rowpar Pharmaceuticals, Scottsdale, AZ, containing stabilized chlorine dioxide without alcohol), and 12.) PerioMed Antimicrobial Oral Rinse (3M ESPE Dental Products; containing 0.63% stannous fluoride without alcohol). Streptococcus salivarius subsp. salivarius ATCC 13419, Veillonella atypica ATCC 17744, and Prevotella melaninogenica ATCC 25845, which are among the most frequent bacterial isolates from the human tongue dorsum, were grown on enriched Brucella blood agar, comprised of 4.3% Brucella agar supplemented with 0.3% bacto-agar, 5% defibrinated sheep blood, 0.2% hemolyzed sheep red blood cells, 0.0005% hemin, and 0.00005% menadione. Pure cell suspensions of each species were adjusted to a 0.5 McFarland turbidity standard (approximately 1.5 x 108 CFU/ml), and combined equally into a standardized mixture. Undiluted 0.1 ml aliquots of the standardized bacterial mixture were spread with sterile cotton-tipped swabs onto non- selective enriched Brucella blood agar culture plates. After inoculation, four 7-mm diameter cylindrical wells were punched into each of the culture plates and filled with 60 μl of one of the commercial mouthrinse formulations, or sterile saline as a negative control. The inoculated culture plates were incubated upright in anaerobic jars containing 85% N2-10% H2-5% CO2 at 37 °C for four days, after which the diameter of inhibition zones against the standardized bacterial mixture at each well was measured at three locations to the nearest millimeter with a Boley gauge. Differences in mean bacterial inhibition zones (after subtraction of the agar well diameter) among the mouthrinse formulations and sterile saline were evaluated using a one-way analysis-of-variance and a post-hoc Tukey honestly significant difference test, with a Bonferroni adjustment for multiple comparisons. A P-value of < 0.05 was required for statistical significance. Results: Perio-Aid Treatment exhibited significantly greater in vitro antimicrobial inhibition than the other tested mouthrinse formulations and sterile saline, followed in descending in vitro antibacterial activity by Paroex, Peridex, Perio-Aid Maintenance, Halita, Crest Pro-Health Clinical, Therasol, Listerine Cool Mint Zero Alcohol, and PerioShield. Listerine Cool Mint with alcohol, Closys, and PerioMed were not significantly different from sterile saline in antibacterial in vitro activity. Conclusions: The mouthrinse containing 0.12% chlorhexidine gluconate plus 0.05% cetylpyridinium chloride (Perio-Aid Treatment) exerted the greatest in vitro inhibitory potential against a combination of three bacterial species frequently predominant on the human tongue dorsum. Significantly less antibacterial effects were found with chlorhexidine gluconate or cetylpyridinium chloride alone, or chlorhexidine gluconate at lower concentrations in combination with cetylpyridinium chloride. The relative lack of in vitro antibacterial activity of mouthrinses comprised of essential oils with alcohol, stabilized chlorine dioxide, or stannous fluoride raises questions about their potential clinical effectiveness against dorsal tongue surface biofilms and oral halitosis.
Temple University--Theses

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50

Ooi, Nicola Chooi Twan. "Antibacterial activity and mechanism of action of lipophilic antioxidants." Thesis, University of Leeds, 2013. http://etheses.whiterose.ac.uk/5905/.

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Abstract:

The emergence and spread of antibiotic resistance hampers effective treatment of bacterial infections. This is particularly the case for infections involving a biofilm component, as the activity of existing antibacterial drugs against these surface-attached communities is limited. The work presented in this thesis sought to identify and characterise compounds with antibacterial and antibiofilm activity against the important pathogen, Staphylococcus aureus. Antistaphylococcal activity was assessed for 16 antioxidants that are used in cosmetics, traditional medicines or as food additives, and which have been reported previously to have some antibacterial activity. Initial experiments with tert-butylhydroquinone (TBHQ) showed that activity that had previously been ascribed to the antioxidant, was a consequence of its conversion to tert-butylbenzoquinone (TBBQ) under culture conditions. TBBQ displayed innate bactericidal activity against S. aureus that was effected through perturbation of the bacterial membrane. The other antioxidants also inhibited staphylococcal growth through perturbation of the cytoplasmic membrane, and compounds that displayed selective action against bacterial membranes were identified. Of the agents with bacterial specificity, TBBQ, celastrol and nordihydroguaiaretic acid (NDGA) also eradicated staphylococcal biofilms; a rare property amongst antibacterial agents. Although these antioxidants exhibited a similar membrane-damaging mode of action, their mechanisms of antibiofilm activity differed. TBBQ eradicated preformed biofilms through sterilisation of slow-growing and persister cell populations, whilst celastrol and NDGA caused physical disruption of the biofilm. All three antioxidants acted synergistically with gentamicin against biofilms, eradicating surface attached populations at concentrations that did not cause irritation or visible damage to a human skin equivalent. The potent and selective antibacterial activity, and low resistance potential upon extended subculture, suggest that these compounds could be used topically in combination with gentamicin to treat infected wounds.

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Dissertations / Theses on the topic 'Antifungal and antibacterial activity'

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