Artigos de revistas: "HPLC UV-VIS/DAD"

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Jančářová, I., A. Vondráčková, A. Šlampová e V. Kubáň. "Capillary electrophoretic and liquid chromatographic determination of synthetic dyes in non-alcoholic drinks and wine samples". Czech Journal of Food Sciences 18, No. 2 (1 de janeiro de 2000): 41–48. http://dx.doi.org/10.17221/8307-cjfs.

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Synthetic dyes in wine, juices, lemonades, instant and non-alcoholic drinks were determined by capillary electrophoresis (CE) and liquid chromatography (HPLC) with UV-VIS diode-array detection (DAD). The results were in the very good agreement (the relative deviations D < 16%, D < 14% and D < 15% between CE/UV-VIS, CE/HPLC and HPLC/UV-VIS, respectively, D < 6% in majority of samples) with those obtained by UV-VIS spectrophotometry. A borate/phosphate buffer of pH 9.0 (12.5mM borate and 12.5mM phosphate) containing 40mM sodium dodecylsulfate (SDS) was selected as an electrolyte for CE. A 50mM phosphate buffer and 5mM tetrabutylammonium hydroxide (TBAOH) water solution of pH 4.2 in 38% (v/v) acetonitrile were used as a mobile phase for isocratic HPLC separation on Sepharon SGX C18 (3 × 150 mm, 5 µm) column. RSDs for individual colorants were < 0.5% for migration times, < 3% for electrophoretic peak areas, < 0.9% for retention times and < 2.4% for HPLC peak areas. Limits of quantitations (LOQs for 10 S/N) were 1.5–3.3 mg/l for CE when using 50 µm I.D. separation capillary or 0.2 to 0.4 mg/l for HPLC.

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Pereira, Ana C., Marco S. Reis, Pedro M. Saraiva e José C. Marques. "Madeira wine ageing prediction based on different analytical techniques: UV–vis, GC-MS, HPLC-DAD". Chemometrics and Intelligent Laboratory Systems 105, n.º 1 (janeiro de 2011): 43–55. http://dx.doi.org/10.1016/j.chemolab.2010.10.009.

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Jerković, Igor, Marina Kranjac, Zvonimir Marijanović, Marina Zekić, Ani Radonić e Carlo Tuberoso. "Screening of Satureja subspicata Vis. Honey by HPLC-DAD, GC-FID/MS and UV/VIS: Prephenate Derivatives as Biomarkers". Molecules 21, n.º 3 (21 de março de 2016): 377. http://dx.doi.org/10.3390/molecules21030377.

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Pinto, Catarina, e J. Sérgio Seixas de Melo. "The molecules of color in Portuguese postage stamps (1857–1909)". Pure and Applied Chemistry 90, n.º 3 (23 de fevereiro de 2018): 435–45. http://dx.doi.org/10.1515/pac-2017-0701.

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AbstractThe nature of the pigments or dyes used to dye the first Portuguese postage stamps has remained unknown until now. In this work, a study has been made of the inks used for red, rose, purple and orange colors in a selected number of Portuguese postage stamps from the period 1857 to 1909. This is based on analysis involving a variety of techniques (X-ray fluorescence, UV-Vis spectroscopy, HPLC-MS/HPLC-DAD, steady and time resolved fluorescence). It was found that the inks included, among others, the inorganic pigments cinnabar (HgS), lead oxide (Pb3O4) and chromate (PbCrO4), lead sulphide (PbS), and the organic compounds carminic acid and Eosin Y. The study demonstrated a non-destructive analysis method for identification of two molecules of color involving the UV-Vis (for carminic acid and Eosin Y) and fluorescence spectra, together with quantum yields and lifetimes (for Eosin Y).

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Di Ciaccio, Lucía S., Alejandra V. Catalano, Paula G. López, Dante Rojas, Diego Cristos, Renée H. Fortunato e Adriana E. Salvat. "In Vitro Antifungal Activity of Peltophorum dubium (Spreng.) Taub. extracts against Aspergillus flavus". Plants 9, n.º 4 (2 de abril de 2020): 438. http://dx.doi.org/10.3390/plants9040438.

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Aspergillus flavus is a filamentous, saprophytic fungus, whose colonization occurs mainly in cereal grains and oilseeds once harvested. Under certain conditions, it could produce mycotoxins called aflatoxins, known as powerful human liver carcinogens. The aim of the present study was to describe the antifungal activity of extracts of Peltophorum dubium, a species from northern Argentina (Oriental Chaco), against A. flavus. The antifungal activities of different collection sites are reported. The extracts exhibited a minimum inhibitory concentration of 125 µg/mL, and the differences between the treatments and the inoculum control were 11 mm of P. dubium A and 10 mm of P. dubium F in colony growth. Moreover, hyphae treated with the extracts stained blue with Evans blue showed alterations in the membrane and/or cell wall, allowing the dye income. Bio-guided fractionation, High Performance Liquid Chromatography diode array ultraviolet/visible (HPLC UV/VIS DAD), and Ultra-High Performance Liquid Chromatography Electrospray Ionization Mass Spectrometry (UPLC ESI-MS) analyses were conducted to characterize the extracts and their active fractions. The HPLC UV/VIS DAD analysis allowed the determination of the presence of flavonoids (flavonols and flavones), coumarins, terpenes, and steroids. UPLC ESI/MS analysis of active fractions revealed the presence of Kaempferol, Apigenin, Naringenin, Chrysin and Daidzein.

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Mărghitaş, Liviu Al, Daniel S. Dezmirean e Otilia Bobiş. "Important Developments in Romanian Propolis Research". Evidence-Based Complementary and Alternative Medicine 2013 (2013): 1–9. http://dx.doi.org/10.1155/2013/159392.

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The most important developments in propolis analysis and pharmacological properties are discussed. In order to help in the Romanian propolis standardization, different methodologies for chemical composition analysis (UV-VIS, HP-TLC, and HPLC-DAD) are reviewed using new approaches and software (fuzzy divisive hierarchical clustering approach and ChromQuest software) and compared with international studies made until now in propolis research. Practical applications of Romanian propolis in medicinal therapy and cosmetics are reviewed, and quality criteria for further standardization are proposed.

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Šivel, M., S. Kráčmar, B. Fišera M Klejdus e V. Kubáň. "Lutein content in marigold flower (Tagetes erecta L.) concentrates used for production of food supplements". Czech Journal of Food Sciences 32, No. 6 (27 de novembro de 2014): 521–25. http://dx.doi.org/10.17221/104/2014-cjfs.

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The RP-HPLC with UV-VIS DAD detection was employed for the separation, identification, and quantification of lutein content in Marigold flower (Tagetes erecta L.) concentrates used for the production of food supplements. The concentrates commercially available in encapsulated (“granules” – 16 samples) and powder (18 samples) forms were analysed. Only 10 samples showed lutein levels complying with lutein contents declared by the manufacturers. Marigold extract in the encapsulated form proved to be more stable against oxidation than the extract in the powder form.  

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Konieczynski, Pawel. "Principal component analysis in interpretation of the results of HPLC-ELC, HPLC-DAD and essential elemental contents obtained for medicinal plant extracts". Open Chemistry 11, n.º 4 (1 de abril de 2013): 519–26. http://dx.doi.org/10.2478/s11532-012-0197-9.

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AbstractPrincipal component analysis (PCA) was applied to compare its usefulness with cluster analysis (CA), and factorial k-means analysis (fkm), for evaluating the results obtained using HPLC-DAD, HPLC-ELC and spectroscopic techniques (AAS and UV/VIS spectrometry for determining content of N, P, Fe and Cu) in aqueous extracts of seven medicinal plants. These represented the following plant species that are rich in flavonoids: Betula verrucosa Ehrh., Equisetum arvense L., Polygonum aviculare L., Viola tricolor L., Crataegus oxyacantha L., Sambucus nigra L. and Helichrysum arenarium (L.) Moench. The databases analyzed comprised four sets: 1) results obtained by the use of HPLC-DAD detection, 2) results obtained by the use of electrochemical detection (HPLC-ELC), 3) results for determining elements — total and water-extractable species, and 4) all data combined. Application of statistical methods allowed the samples to be classified into four groups: 1) Crataegus, Sambucus, 2) Equisetum, Polygonum and Viola, 3) Betula, and 4) Helichrysum, which were differentiated by characteristic patterns. PCA supported by CA, was the most suitable method, because it simultaneously allowed for reduction of multidimensionality of the databases, grouped the samples into four clusters, and made possible selection of the factors responsible for differentiation of the plant materials studied.

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Mateos-Maces, Lourdes, José Luis Chávez-Servia, Araceli Minerva Vera-Guzmán, Elia Nora Aquino-Bolaños, Jimena E. Alba-Jiménez e Bethsabe Belem Villagómez-González. "Edible Leafy Plants from Mexico as Sources of Antioxidant Compounds, and Their Nutritional, Nutraceutical and Antimicrobial Potential: A Review". Antioxidants 9, n.º 6 (20 de junho de 2020): 541. http://dx.doi.org/10.3390/antiox9060541.

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A review of indigenous Mexican plants with edible stems and leaves and their nutritional and nutraceutical potential was conducted, complemented by the authors’ experiences. In Mexico, more than 250 species with edible stems, leaves, vines and flowers, known as “quelites,” are collected or are cultivated and consumed. The assessment of the quelite composition depends on the chemical characteristics of the compounds being evaluated; the protein quality is a direct function of the amino acid content, which is evaluated by high-performance liquid chromatography (HPLC), and the contribution of minerals is evaluated by atomic absorption spectrometry, inductively coupled plasma-optical emission spectrometry (ICP-OES) or ICP mass spectrometry. The total contents of phenols, flavonoids, carotenoids, saponins and other general compounds have been analyzed using UV-vis spectrophotometry and by HPLC. For the determination of specific compounds such as phenolic compounds, flavonoids, organic acids and other profiles, it is recommended to use HPLC-DAD, UHPLC-DAD, UFLC-PDA or gas chromatography-mass spectrometry. The current biochemical analysis and biological evaluations were performed to understand the mechanisms of action that lead to decreased glucose levels and lipid peroxidation, increased hypoglycemic and antitumor activity, immune system improvement, increased antibacterial and antifungal activity and, in some cases, anti-Helicobacter pylori activity.

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Sholihah, Shofuro, Norisca Aliza Putriana e Rimadani Pratiwi. "Review Metode Analisis Warfarin dalam Plasma dengan Berbagai Instrumen". Jurnal Sains Farmasi & Klinis 8, n.º 2 (6 de agosto de 2021): 128. http://dx.doi.org/10.25077/jsfk.8.2.128-144.2021.

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Warfarin merupakan obat antikoagulan oral yang digunakan untuk menangani penyakit terkait dengan tromboembolisme. Warfarin memiliki indeks terapi yang sempit serta memiliki kecenderungan berinteraksi dengan obat maupun herba sehingga membutuhkan pemantauan yang cermat pada efek farmakologi yang ditimbulkan. Penentuan pemberian dosis serta pengamatan efek dari interaksi warfarin dengan obat atau herba salah satunya dapat diketahui dengan menganalisis konsentrasi warfarin dalam plasma darah. Artikel ini merupakan kajian pustaka yang bertujuan untuk memberikan tinjauan mengenai metode yang digunakan untuk menganalisis konsentrasi warfarin dalam plasma darah serta teknik preparasi sampelnya. Metode yang digunakan dalam review artikel ini menggunakan penelusuran melalui basis data PubMed®. Hasil yang didapatkan bahwa metode yang umum digunakan untuk determinasi warfarin dalam plasma darah yakni high-performance liquid chromatography (HPLC) serta ultra-HPLC dengan detektor ultraviolet (UV), fluoresensi (FLD), diode array (DAD), maupun spektroskopi massa (MS). Metode lainnya yaitu spektrofotometri UV/Vis dan spektrofotometri fluoresensi serta elektroforesis. Dari metode tersebut, metode HPLC dengan detektor spektroskopi massa paling banyak digunakan untuk menganalisis warfarin serta teknik preparasi sampel yang umum digunakan yakni preparasi sampel yang umum digunakan yakni presipitasi protein menggunakan asetonitril sebagai protein presipitan serta penambahan asam untuk meningkatkan nilai recovery warfarin dari plasma darah

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Bunghez, Florina, Carmen Socaciu, Florina Zagrean, Raluca Maria Pop, Floricuta Ranga e Florina Romanciuc. "Characterisation of an Aromatic Plant-based Formula using UV-Vis Spectroscopy, LC–ESI(+)QTOF-MS and HPLC-DAD Analysis". Bulletin of University of Agricultural Sciences and Veterinary Medicine Cluj-Napoca. Food Science and Technology 70, n.º 1 (13 de novembro de 2013): 16. http://dx.doi.org/10.15835/buasvmcn-fst:9635.

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Abstract. It is known for a long time that seasoning/condimentary herbs have antioxidant activity and antibacterial properties, being good natural alternatives for disease prevention. The different efficiency of these plants is assigned to their bioactive molecules, stability and bioavailability. In the present study seven aromatic herbs (basil, thyme, oregano, rosemary, clove, cinnamon and sage) were investigated individually. A new product was developed using basil, thyme, oregano, rosemary, clove, cinnamon and sage, according to a default recipe. The characterization of each plant aimed to identify the specific “fingerprint” by its main bioactive molecules and the “traceability” of these molecules in the new product, made by mixing the selected plants according to a default recipe. In order to determine the main bioactive compounds of the individual plants composition, in comparison with the new plant-based (EPC) formula, high throughput techniques like UV-Vis spectroscopy and LC-QTOF-MS spectrometry were used. The most important bioactive compounds determined in the studied herbs, which may exert antioxidant activity and antibacterial properties, were phenolic compounds (phenolic acids, flavonoids), quinones, clorophylls as well some polar terpenoids. The fingerprints are providing comprehensive and accurate information about the compounds that may exert antimicrobial properties. In order to assure the biological effects and the bioavailability of the polyphenols and the secondary metabolites we have to consider the antagonistic and synergistic effect that the metabolites can exert on each other.

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Miyagusuku-Cruzado, Gonzalo, Israel García-Cano, Diana Rocha-Mendoza, Rafael Jiménez-Flores e M. Monica Giusti. "Monitoring Hydroxycinnamic Acid Decarboxylation by Lactic Acid Bacteria Using High-Throughput UV-Vis Spectroscopy". Molecules 25, n.º 14 (9 de julho de 2020): 3142. http://dx.doi.org/10.3390/molecules25143142.

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Hydroxycinnamic acid (HCA) decarboxylation by lactic acid bacteria (LAB) results in the production of 4-vinylplenols with great impact on the sensorial characteristics of foods. The determination of LAB decarboxylating capabilities is key for optimal strain selection for food production. The activity of LAB strains from the Ohio State University—Parker Endowed Chair (OSU-PECh) collection potentially capable of synthesizing phenolic acid decarboxylase was evaluated after incubation with HCAs for 36 h at 32 °C. A high-throughput method for monitoring HCAs decarboxylation was developed based on hypsochromic shifts at pH 1.0. Out of 22 strains evaluated, only Enterococcus mundtii, Lactobacillus plantarum and Pediococcus pentosaceus were capable of decarboxylating all p-coumaric, caffeic and ferulic acids. Other strains only decarboxylated p-coumaric and caffeic acid (6), only p-coumaric acid (2) or only caffeic acid (1), while 10 strains did not decarboxylate any HCA. p-Coumaric acid had the highest conversion efficiency, followed by caffeic acid and lastly ferulic acid. Results were confirmed by HPLC-DAD-ESI-MS analyses, showing the conversion of HCAs into their 4-vinylphenol derivatives. This work can help improve the sensory characteristics of HCA-rich foods where fermentation with LAB was used during processing.

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Sun, Hai Hong, Xiao Mei Mo e Ye Miao Qian. "Comparison of HPLC and Spectrophotometry Methods on Quantitative Determination of Formaldehyde in Water Based Coatings". Advanced Materials Research 816-817 (setembro de 2013): 433–38. http://dx.doi.org/10.4028/www.scientific.net/amr.816-817.433.

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To explore and compare the reliability of the quantitative determination of formaldehyde content of water based coatings, the high performance liquid chromatography (HPLC) after derivatization to 2.4-dinitrophenylhydazone and UV-VIS spectrophotometry were studied, respectively. HPLC was performed on a C18 column with acetonitrile/water (65/35, V/V) as mobile phase at a flow rate of 1.0 mL/min, and analyses was detected using Photodode Array Detector (DAD) at the wavelength of 360 nm. And formaldehyde was determined with spectrophotometry at 435nm. The result showed the standard curve of formaldehyde by the HPLC method was linear in the range of 0.1-5.0 mg/L (R2=0.9998). The detection limit was 0.96mg/kg, recoveries were ranging from 96.2% to 101.3%. The linear range of formaldehyde by the spectrophotometric method was 0.1～5.0 mg/L (R2=0.9995), and the detection limit was 5.93mg/kg, recoveries were ranging from 98.5% to 105.3%. In conclusion, both the two methods can be used for quantitative analysis of formaldehyde in water based coatings, and the major advantages of HPLC are quick, simple and sensitive.

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Csernatoni, Florina, Carmen Socaciu, Raluca Maria Pop, Floricuta Ranga, Florina Bunghez e Florina Romanciu. "Comparative Fingerprint of Aromatic Herbs and Yeast Alcoholic Extracts used as Ingredients for Promen, a Prostate Preventive Nutraceutical". Bulletin of University of Agricultural Sciences and Veterinary Medicine Cluj-Napoca. Food Science and Technology 70, n.º 1 (13 de novembro de 2013): 45. http://dx.doi.org/10.15835/buasvmcn-fst:9719.

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The aim of this study was to characterize and identify different bioactive compounds in plant sources and yeast powders to obtain an original nutraceutical (Promen) which has beneficial effects in prostate disease prevention. Seven plant and fruit sources, namely nettle (Urtica dioica), green tea (Camellia sinensis), fluff with small flowers (Epilobium parviplorum), tomato (Solanum licopersicum), sea buckthorn (Hippophae rhamnoides), pumpkin (Cucurbita maxima), sunflower (Helianthus annus) and lyophilized beer yeast (Saccharomyces cerevisiae) were investigated. Methanolic extracts were prepared using 15% plant concentration and the purified fractions were analyzed using high throughput techniques like UV-VIS spectroscopy, high performance liquid chromatography coupled with photodiode array detection (HPLC-DAD) and mass spectrometry LC-QTOF -MS. The majority of the investigated plants were rich in phenolic derivatives, polyphenols (flavonoid glucosides), while yeast was rich in aminoacids, peptides and vitamins B. The major compounds identified were: Juglone, Resveratrol, Quercetin, Epigallocatechin, Gallocatechin, Biochanin A, Isorhamnetin 3-O-glucoside 7-O-rhamnoside, Quercetin 3-O-galactoside 7-O-rhamnoside, Kaempferol 3,7-O-diglucoside and p-Coumaroylquinic acid. The specific biomarkers were identified for both plant extracts used as ingredients to obtain an nutraceutical Promen. Combined UV-Vis spectroscopy, HPLC-PDA chromatography and LC-MS spectrometry are recommended as accurate, sensible and reliable tools to investigate the plants and nutraceutical fingerprints and to predict the relation between ingredients composition and their health effects.

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Antonova, N. P., E. P. Shefer, N. E. Semenova, S. S. Prokhvatilova, A. M. Kalinin, S. A. Kuchugurin e V. N. Makukhin. "Development of a Comprehensive HPLC Method for Determination of Product-related Impurities and Assay of Active Ingredients in Papaverine Hydrochloride Products". Bulletin of the Scientific Centre for Expert Evaluation of Medicinal Products 11, n.º 1 (10 de março de 2021): 36–43. http://dx.doi.org/10.30895/1991-2919-2021-11-1-36-43.

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Abstract. Papaverine hydrochloride products are used as anticonvulsants in routine medical practice. Most of the approved product specification files include thin-layer chromatography for assessment of product-related impurities and UV spectrophotometry for determination of active pharmaceutical ingredients. An HPLC assay is not used for determination of papaverine hydrochloride in drug dosage forms.The aim of the study was to develop an HPLC test method for determination of product-related impurities and for quantification of papaverine hydrochloride in solutions for injection, tablets, and rectal suppositories.Materials and methods: samples of the following Russian-made papaverine products were used in the study: Papaverine, solution for injection, 20 mg/mL; Papaverine, rectal suppositories, 20 mg; Papaverine, tablets, 40 mg. The Agilent 1260 Infinity II DAD System was used for the HPLC assay, and the Agilent 8453Е UV-Vis System was used for recording UV spectra. The determination of product-related impurities and the assay of active ingredients were performed simultaneously by HPLC using a reversed-phase column Kromasil 100-5-C18, 250×4.6 mm, 5 μm, the gradient elution mode, and detection at 238 nm. Papaverine Hydrochloride USP RS, 99% purity, and Noscapine EP CRS were used as reference standards.Results: the study demonstrated that determination of product-related impurities and assay of active ingredients in papaverine products can be performed simultaneously using HPLC.Conclusions: the authors proposed an HPLC test method for determination of active ingredients in papaverine products, which is aligned with the “consistent standardisation” principle and can be recommended for inclusion into draft monographs for papaverine products.

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Lazzerini, Cristina, Mario Cifelli e Valentina Domenici. "Pigments in extra virgin olive oils produced in different mediterranean countries in 2014: Near UV-vis spectroscopy versus HPLC-DAD". LWT 84 (outubro de 2017): 586–94. http://dx.doi.org/10.1016/j.lwt.2017.06.025.

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Santi, M. M., F. S. Sanches, J. F. M. Silva e P. M. L. Santos. "Determinação do perfil fitoquímico de extrato com atividade antioxidante da espécie medicinal Cordia verbenacea DC. por HPLC-DAD". Revista Brasileira de Plantas Medicinais 16, n.º 2 (junho de 2014): 256–61. http://dx.doi.org/10.1590/s1516-05722014000200014.

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O presente trabalho teve por objetivo investigar a atividade antioxidante dos extratos das folhas de Cordia verbenacea obtido por maceração em etanol e partição em solventes orgânicos. O infuso das folhas também foi investigado. O teor de fenóis totais foi avaliado pelo método de Folin-Ciocalteau e o de flavonoides totais pela formação de complexo com cloreto de alumínio. O extrato etanólico, as subfrações e o infuso foram testados em diversas concentrações para determinar a atividade sequestradora de DPPH expressa em termos de sua CE50. A melhor atividade antioxidante encontrada foi para o extrato em acetato de etila, EA, CE50 15,0 ± 0,5 µg.mL-1. Os ensaios espectrofotométricos revelaram altas concentrações de fenóis e de flavonoides no extrato EA. A análise por HPLC-DAD foi realizada para se obter o perfil de UV-Vis dos picos cromatográficos do extrato EA. As características espectrais foram relacionadas a compostos fenólicos e flavonoídicos.

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Živanović, Slavoljub C., Ružica S. Nikolić e Goran M. Nikolić. "The Influence of Mg(II) and Ca(II) Ions on Rutin Autoxidation in Weakly Alkaline Aqueous Solutions". Acta Facultatis Medicae Naissensis 33, n.º 3 (1 de setembro de 2016): 163–71. http://dx.doi.org/10.1515/afmnai-2016-0018.

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Summary Rutin (quercetin-3-O-rutinoside) is one of the most abundant bioflavonoids with various biological and pharmacological activities. Considering the ubiquitous presence of Mg(II) and Ca(II) ions in biological systems we decided to investigate their influence on the autoxidation of rutin in weakly alkaline aqueous solutions. Changes in UV-Vis spectra recorded during the rutin autoxidation in aqueous solution at pH 8.4 revealed that this process was very slow in the absence of metal ions. The presence of Mg(II) and, especially Ca(II) ion, increased the transformation rate of rutin. UV-Vis spectra recorded after prolonged autoxidation indicated the formation of humic acidlike products in the presence of Mg(II) and Ca(II) ions. Four new compounds formed during the initial stage of rutin autoxidation in the presence of Mg(II) and Ca(II) ions were detected by HPLCDAD. Based on the analysis of their DAD UV-Vis spectra and comparison of their retention times with the retention time value for rutin, we concluded that the initial rutin transformation products were formed by the water addition on double bond in ring C and hydroxylation of ring B. A very small decrease of the initial rutin concentration (4%) was observed by HPLC-DAD in the absence of metal ions for the period of 90 minutes. However, rutin concentration decrease was much larger in the presence of Mg(II) and Ca(II) ions (14% and 24%, respectively). The more pronounced effect of Ca(II) ion on the rutin autoxidation may be explained by the stronger binding of Mg(II) ion to rutin and thus greater stabilizing effect on reaction intermediates caused by its higher ionic potential (charge/ionic radius ratio) in comparison to Ca(II) ion. The results of this study may contribute to the better understanding of interactions of Mg(II) and Ca(II) ions with natural phenolic antioxidants which are important for their various biological activities.

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Jiménez-Holgado, Cristina, Christoforos Chrimatopoulos, Vassilis Stathopoulos e Vasilios Sakkas. "Investigating the Utility of Fabric Phase Sorptive Extraction and HPLC-UV-Vis/DAD to Determine Antidepressant Drugs in Environmental Aqueous Samples". Separations 7, n.º 3 (8 de julho de 2020): 39. http://dx.doi.org/10.3390/separations7030039.

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Depression is considered to be one of the most prevalent mental disorders in humans. Antidepressant drugs are released in large concentrations and cause adverse effects on the environment and/or human health. Fabric Phase Sorptive Extraction (FPSE), a contemporary solid sorbent-handling technique, is a quick, sensitive, and simple analytical process. This paper describes a micro-extraction FPSE procedure coupled with High-Performance Liquid-Chromatography–Photodiode Array Detection (FPSE-HPLC–DAD) for the simultaneous extraction and analysis of five antidepressants, namely citalopram, clozapine, mirtazapine, bupropion and sertraline. Three fabric media (Whatman Cellulose filter, Whatman Microfiber Glass filter and Polylactic acid disks) and two different sol–gel sorbents (polyethylene glycol (PEG 300), alongside poly(ethylene glycol)-block-poly(propylene glycol)-block-poly(ethylene glycol) (PEG-PPG-PEG 5.800)) were tested. The best FPSE device was observed to be the microfiber glass filter coated with PEG 300 sol–gel sorbent. In addition, the parameters that affect the efficiency of the process (FPSE media and sorbents, sample pH, extraction time, elution time, etc.) were optimized. The proposed methodology displays a linear range with absolute recovery values higher than 60%, RSD% of less than 13% and LOQs in the range between 1.9–10.7 μg·L−1. Finally, the method was applied in hospital and urban effluents and lake water samples, but none of the analytes were detected.

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Akgul Kalkan, Esin, Mehtap Sahiner, Dilek Ulker Cakir, Duygu Alpaslan e Selehattin Yilmaz. "Quantitative Clinical Diagnostic Analysis of Acetone in Human Blood by HPLC: A Metabolomic Search for Acetone as Indicator". Journal of Analytical Methods in Chemistry 2016 (2016): 1–7. http://dx.doi.org/10.1155/2016/5176320.

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Using high-performance liquid chromatography (HPLC) and 2,4-dinitrophenylhydrazine (2,4-DNPH) as a derivatizing reagent, an analytical method was developed for the quantitative determination of acetone in human blood. The determination was carried out at 365 nm using an ultraviolet-visible (UV-Vis) diode array detector (DAD). For acetone as its 2,4-dinitrophenylhydrazone derivative, a good separation was achieved with a ThermoAcclaim C18column (15 cm×4.6 mm×3 μm) at retention time (tR) 12.10 min and flowrate of 1 mL min−1using a (methanol/acetonitrile) water elution gradient. The methodology is simple, rapid, sensitive, and of low cost, exhibits good reproducibility, and allows the analysis of acetone in biological fluids. A calibration curve was obtained for acetone using its standard solutions in acetonitrile. Quantitative analysis of acetone in human blood was successfully carried out using this calibration graph. The applied method was validated in parameters of linearity, limit of detection and quantification, accuracy, and precision. We also present acetone as a useful tool for the HPLC-based metabolomic investigation of endogenous metabolism and quantitative clinical diagnostic analysis.

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Gomes, Jadiete T. S., Jackson H. S. Santos, Cesar A. M. Abreu, Eliane B. M. Medeiros, Lucas C. D. Coelho, Rui P. V. Faria, Alírio E. Rodrigues e Nelson M. Lima Filho. "Development and validation of analytical method for mono, di and triacetin analysis by HPLC/UV–Vis/DAD detection with 13C NMR identification". Results in Chemistry 2 (janeiro de 2020): 100063. http://dx.doi.org/10.1016/j.rechem.2020.100063.

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Pawłowicz, Kamil, Dominika Ludowicz, Marta Karaźniewicz-Łada, Kamil Wdowiak e Judyta Cielecka-Piontek. "Analysis of the Composition of Lyophilisates Obtained from Aloe arborescens Gel of Leaves of Different Ages from Controlled Crops". Molecules 26, n.º 11 (27 de maio de 2021): 3204. http://dx.doi.org/10.3390/molecules26113204.

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The aim of the study is to evaluate the composition of lyophilisates obtained from Aloe arborescens leaf gel at the age of one to four years. The leaves were obtained from controlled crops, which allowed to exclude environmental factors as variables. It was confirmed that the lyophilisates obtained from different years of Aloe arborescens leaf gel varied in chromatographic analyses in terms of aloin A and aloenin A content (high-performance liquid chromatography with diode-array detection HPLC-DAD, high-performance liquid chromatography with tandem mass spectrometric detection HPLC-MS/MS). Similarly, while testing the phenolic acids and the sum of polyphenols content, differences in their levels in leaf gel lyophilisates from plants of individual years were observed (spectrophotometric method UV-VIS). The lyophilisate composition analysis showed that the one-year-old leaves were characterized by the highest content of aloin A and aloenin A. While the content of polyphenols, including phenolic acids, was higher in the leaves of older plants. The antioxidant potential of the tested lyophilisates was assessed simultaneously. Regardless of the research model used (CUPRAC, DPPH, ABTS), an antioxidant effect was noted for Aloe arborescens leaves.

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Aires, Alfredo, e Rosa Carvalho. "Rapid Separation of Indole Glucosinolates in Roots of Chinese Cabbage (Brassica rapaSubsp. Pekinensis) by High-Performance Liquid Chromatography with Diode Array Detection". International Journal of Analytical Chemistry 2017 (2017): 1–7. http://dx.doi.org/10.1155/2017/5125329.

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Glucosinolates are a class of sulphur-containing plant compounds with diverse biological properties. They have been found exclusively in the Brassicaceae family plants and studied exhaustively in biosynthetic and application perspectives. The aim of this current study is to present a simple and updated method to quantify indole glucosinolate content in hairy root cultures of Chinese cabbage by HPLC-DAD-UV/Vis. Method validation controls were performed and recovery experiments were assayed. The data was statically treated and compared with published works. The current method allowed a feasible identification of indole glucosinolates and it was possible to identify accurately three indole glucosinolate compounds (glucobrassicin, 4-methoxyglucobrassicin, and 1-methoxyglucobrassicin) in roots of Chinese cabbage. The method demonstrated a good linearity (R2>0.99), a good precision, and selectivity sensitivity. In conclusion, this protocol provides an accessible method to extract and quantify glucosinolates in plant samples. Thus, based on our results, the method is valid and can be extended to other plant or food matrices.

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Ghosh, Pranabesh, Chandrima Das, Swagata Biswas, Sudip Kumar Nag, Alolika Dutta, Maitrayee Biswas, Sayantan Sil et al. "Phytochemical composition analysis and evaluation of in vitro medicinal properties and cytotoxicity of five wild weeds: A comparative study". F1000Research 9 (2 de junho de 2020): 493. http://dx.doi.org/10.12688/f1000research.22966.1.

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Background: Medicinal plants are a source of phytochemicals and they are used for the treatment of several oxidative stress-related or other diseases for their effectiveness, low toxicity and easy availability. Five traditionally used and less characterized herbaceous weeds of West Bengal, India, namely, Heliotropium indicum, Tridax procumbens, Cleome rutidosperma, Commelina benghalensis and Euphorbia hirta, were investigated for the current research study. Methods: Aqueous and 70% ethanolic extracts of the leaves were analyzed for estimation of essential phytochemicals and to evaluate their in vitro antioxidant status, medicinal properties and cytotoxic effects. To the best of our knowledge, several assays and comparative evaluations using these herbs are reported for the first time. For quantitative study, UV-vis spectrophotometry and high-performance liquid chromatography with diode array detector HPLC-DAD techniques were used. Antibacterial properties were investigated using the Kirby-Bauer disc diffusion method. For in vitro anti-lithiatic study, a titration method was used. The cell viability assay was done using peripheral blood mononuclear cells. Results: The aqueous extract exhibits higher content of polyphenols, flavonoids, tannins and inhibition percentage values for free radical scavenging assays, whereas the 70% ethanolic extract exhibits higher content of alkaloids and cardiac glycosides. HPLC-DAD analysis of 70% ethanolic extracts led us to identify 10 predominant phenolic constituents. Euphorbia hirta extracts showed minimum cytotoxicity (cell death ~2.5% and 4% in water and 70% ethanolic extract, respectively), whereas Cleome rutidosperma and Tridax procumbens’ 70% ethanolic extracts showed higher cell death (~13% and 28%, respectively), compared with the control (cell death ~10-12%). Conclusions: The study concluded that of all the medicinal weeds selected for the current study, Euphorbia hirta possesses the highest amount of bioactive compounds and hence exhibits the highest in vitro antioxidant activity and promising in vitro medicinal properties.

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Jerković, Igor, Carlo Ignazio Giovanni Tuberoso, Goran Baranović, Zvonimir Marijanović, Marina Kranjac, Lidija Svečnjak e Piotr Marek Kuś. "Characterization of Summer Savory (Satureja hortensis L.) Honey by Physico-Chemical Parameters and Chromatographic / Spectroscopic Techniques (GC-FID/MS, HPLC-DAD, UV/VIS and FTIR-ATR)". Croatica Chemica Acta 88, n.º 1 (2015): 15–22. http://dx.doi.org/10.5562/cca2514.

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Piaskowski, Krzysztof, Renata Świderska-Dąbrowska, Aleksandra Kaleniecka e Paweł K. Zarzycki. "Advances in the Analysis of Water and Wastewater Samples Using Various Sensing Protocols and Microfluidic Devices Based on PAD and μTAS Systems". Journal of AOAC INTERNATIONAL 100, n.º 4 (1 de julho de 2017): 962–70. http://dx.doi.org/10.5740/jaoacint.17-0170.

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Abstract The main goal of this review is to summarize practical approaches concerning the application of microfluidic systems for the analysis of various biomarkers and pollutants, as well as microbes, in water and wastewater matrixes. This problem involves multidisciplinary expertise combining research knowledge from various areas, including wet chemistry, biochemistry, physical chemistry, molecular biology, genetics, signal processing, microelectronics material science, and separation science. It has been documented that fairly primitive but fast and inexpensive screening methods involving paper-based analytical devices (PADs) and micro total analytical systems (μTAS) can be considered as serious alternatives to their more advanced counterparts such as GC, HPLC, and capillary electrophoresis coupled to various sophisticated detectors (e.g., multiwavelength spectrophotometers such as UV-Vis/DAD and mass spectrometers). The main advantage of PAD- and μTAS-driven technology is that such sensing devices may work under on-site and real-time conditions and measure a number of physical parameters and chemical factors simultaneously. Moreover, hybrid miniaturized analytical systems may combine sensing and data acquisition modules with common mobile phones and electronic devices working with global positioning systems and communicating through the Internet.

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de Souza, Maiara P., Tiele M. Rizzetti, Michele Hoeltz, Mainara Dahmer, João A. Júnior, Gisele Alves, Lisianne B. Benitez e Rosana C. S. Schneider. "Bioproducts characterization of residual periphytic biomass produced in an algal turf scrubber (ATS) bioremediation system". Water Science and Technology 82, n.º 6 (27 de julho de 2020): 1247–59. http://dx.doi.org/10.2166/wst.2020.343.

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Abstract The transformation of residual biomass from bioremediation processes into new products is a worldwide trend driven by economic, environmental and social gain. The present study aimed to evaluate the potential for obtaining bioproducts of technological interest from the remaining periphytic biomass formed during a bioremediation process with an algal turf scrubber (ATS) system installed in a lake catchment. Different methodologies were used according to the target bioproduct. Analyses were performed by high performance liquid chromatography with diode array detector (HPLC/DAD), gas chromatography mass spectrometry (GC-MS), ultraviolet–visible spectroscopy (UV-VIS) and inductively coupled plasma optical emission spectrometry (ICP-OES). The results demonstrated that the periphytic biomass presented potential since protein (17.7%), carbohydrates (22.4%), total lipids (3.3%) with 3.6 mg mL−1 of fatty acids, antioxidants (144.5 μmol Trolox eq. g−1) and chlorophyll a, chlorophyll b and carotenoids (1,719.7 μg mL−1, 541.2 μg mL−1 and 317.7 μg mL−1, respectively) were obtained. Inorganic analysis presented a value of 42.3 ± 2.58% of total ash and metal presence was detected, indicating bioaccumulation. The properties found in periphyton strengthen the possibility of its application in different areas, ensuring bioremediation efficiency.

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Kaczmarek, A., J. Cielecka-Piontek, P. Garbacki, K. Lewandowska, W. Bednarski, B. Barszcz, P. Zalewski, W. Kycler, I. Oszczapowicz e A. Jelińska. "Radiation Sterilization of Anthracycline Antibiotics in Solid State". Scientific World Journal 2013 (2013): 1–7. http://dx.doi.org/10.1155/2013/258758.

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The impact of ionizing radiation generated by a beam of electrons of 25–400 kGy on the stability of such analogs of anthracycline antibiotics as daunorubicin (DAU), doxorubicin (DOX), and epidoxorubicin (EPI) was studied. Based on EPR results, it was established that unstable free radicals decay exponentially with the half-time of 4 days in DAU and DOX and 7 days in EPI after irradiation. Radiation-induced structural changes were analyzed with the use of spectrophotometric methods (UV-Vis and IR) and electron microscope imaging (SEM). A chromatographic method (HPLC-DAD) was applied to assess changes in the contents of the analogs in the presence of their impurities. The study showed that the structures of the analogs did not demonstrate any significant alterations at the end of the period necessary for the elimination of unstable free radicals. The separation of main substances and related substances (impurities and potential degradation products) allowed determining that no statistically significant changes in the content of particular active substances occurred and that their conversion due to the presence of free radicals resulting from exposure to an irradiation of 25 kGy (prescribed to ensure sterility) was not observed.

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Canuti, Valentina, Lorenzo Cecchi, Mohamad Khatib, Lorenzo Guerrini, Nadia Mulinacci e Bruno Zanoni. "A New Extract from Pomegranate (Punica granatum L.) By-Products as a Potential Oenological Tannin: Preliminary Characterization and Comparison with Existing Commercial Products". Molecules 25, n.º 19 (28 de setembro de 2020): 4460. http://dx.doi.org/10.3390/molecules25194460.

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Oenotannins are nowadays widely used as co-adjuvant in the winemaking process. The increasing cultivation and consumption of pomegranate (Punica granatum L.) leads to high amounts of by-products, mainly peels. Aim of this study was to propose a dried tannin-rich extract from pomegranate by-products as a new oenotannin. A decoction was prepared from mesocarp of the Wonderful pomegranate variety only using hot water as extracting solvent. The dried decoction was physical-chemically characterized and compared to 7 existing commercial oenotannins from different botanical origin (grape seed, oak, gallnut), according to UV-Vis Spectroscopy, Colorimetric analysis (CIELab), gelatin index, reactivity to proteins, HPLC-DAD, DPPH, and Total Polyphenols content by both Folin-Ciocalteu and the International Organization of Vine and Wine (OIV) methods. Data showed the lowest antiradical (AR) and total polyphenolic content (TPC) for the pomegranate tannin but also the highest AR/TPC ratio suggesting a good radical scavenging potential of this new tannin. Pomegranate tannin showed high reactivity with proteins, a unique chromatographic profile, and a low color impact. The new pomegranate tannin showed an interesting potential for oenological applications in particular for reducing the use of sulfites during vinification and for the white wine stabilization.

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Hanganu, Daniela, Mihaela Niculae, Irina Ielciu, Neli-Kinga Olah, Melania Muntean, Ramona Burtescu, Răzvan Ștefan et al. "Chemical Profile, Cytotoxic Activity and Oxidative Stress Reduction of Different Syringa vulgaris L. Extracts". Molecules 26, n.º 11 (22 de maio de 2021): 3104. http://dx.doi.org/10.3390/molecules26113104.

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Syringa vulgaris L. (common lilac) is one of the most popular ornamental species, but also a promising not comprehensively studied source of bioactive compounds with important therapeutic potential. Our study was designed to characterize the chemical composition and to assess the antioxidant and cytotoxic properties of ethanolic extracts obtained from S. vulgaris L. flowers, leaves, bark, and fruit. The chemical profile of the ethanolic extracts was investigated using chromatographic (HPLC-DAD-ESI+, GC-MS) and spectral (UV-Vis, FT-IR) methods, while the protective effect against free radicals was evaluated in vitro by different chemical assays (DPPH, FRAP, CUPRAC). The cytotoxic activity was tested on two tumoral cell lines, HeLa, B16F10, using the MTT assay. Significant amounts of free or glycosylated chemical components belonging to various therapeutically important structural classes, such as phenyl-propanoids (syringin, acteoside, echinacoside), flavonoids (quercetin, kaempferol derivatives) and secoiridoids (secologanoside, oleuropein, 10-hydroxy oleuropein, demethyloleuropein, syringalactone A, nuzhenide, lingstroside) were obtained for the flowers, leaves and bark extracts, respectively. Furthermore, MTT tests pointed out a significant cytotoxic potential expressed in a non-dose-dependent manner toward the tumoral lines. The performed methods underlined that S. vulgaris extracts, in particular belonging to flowers and leaves, represent valuable sources of compounds with antioxidant and antitumoral potential.

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Bobková, Alica, Alžbeta Demianová, Ľubomír Belej, Ľuboš Harangozo, Marek Bobko, Lukáš Jurčaga, Katarína Poláková, Monika Božiková, Matúš Bilčík e Július Árvay. "Detection of Changes in Total Antioxidant Capacity, the Content of Polyphenols, Caffeine, and Heavy Metals of Teas in Relation to Their Origin and Fermentation". Foods 10, n.º 8 (6 de agosto de 2021): 1821. http://dx.doi.org/10.3390/foods10081821.

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Tea (Camellia sinensis) is widely sought for beverages worldwide. Heavy metals are often the main aims of the survey of teas, given that the use of agricultural fertilization is very frequent. Some of these may affect the content of bioactive compounds. Therefore, in this study, we analyzed fermented and non-fermented teas of a single plant origin from Japan, Nepal, Korea, and China, and described mutual correlations and changes in the total antioxidant capacity (TAC), and the content of polyphenols (TPC), caffeine, and heavy metals in tea leaves, in relation to the origin and fermentation process. Using UV-VIS spectrophotometry and HPLC-DAD, we determined variations in bioactive compounds’ content in relation to the fermentation process and origin and observed negative correlations between TAC and TPC. Heavy metal content followed this order: Mn > Fe > Cu > Zn > Ni > Cr > Pb > Co > Cd > Hg. Given the homogenous content of these elements in relation to fermentation, this paper also describes the possibility of using heavy metals as determinants of geographical origin. Linear Discriminant Analysis showed an accuracy of 75% for Ni, Co, Cd, Hg, and Pb, explaining 95.19% of the variability between geographical regions.

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Crupi, Pasquale, Giambattista Debiase, Gianvito Masi, Francesca Mangione e Luigi Tarricone. "Harpin Proteins Improve Bioactive Compounds Content in Crimson Seedless Table Grape". Open Bioactive Compounds Journal 7, n.º 1 (31 de maio de 2019): 1–7. http://dx.doi.org/10.2174/1874847301907010001.

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Background: Frequently, in warm climates such as Mediterranean areas, a red-pink table grape ‘Crimson Seedless’ does not reach a good berry skin color; and an acceptable anthocyanin bioactive compounds content, responsible for the red color of berries. Harpin proteins are biotechnologically developed bio-activators that, if applied on plants during the growing period, trigger the expression of hundreds of genes among which those associated with the biosynthesis of bioactive compounds (such as anthocyanins). Aim: This research aimed at using harpin proteins to test their suitability in improving the grape skin color. Methods and Materials: Beta-harpin protein 1% p.a. (400 g/Ha) was applied to ‘Crimson Seedless’ vines three times at the beginning of veraison. Six samplings were carried out for both the treated and control grapes until commercial harvest. In the skin extracts, total and individual anthocyanins content was determined by UV-Vis and RP-HPLC-DAD analyses, respectively. Results: The collected results confirmed that the application of harpin proteins effectively stimulated the anthocyanin biosynthesis leading to make peonidin-3O-glucoside, cyanidin-3O-glucoside, and malvidin-3O-glucoside values from 2 to almost 10 folds higher in treated grapes than in control grapes (P < 0.05). Conclusion: Actually, harpin proteins improved the color of the berry skin, leading to a significantly higher concentration of anthocyanins in treated than in control grapes.

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Carail, Michel, e Catherine Caris-Veyrat. "Carotenoid oxidation products: From villain to saviour?" Pure and Applied Chemistry 78, n.º 8 (1 de janeiro de 2006): 1493–503. http://dx.doi.org/10.1351/pac200678081493.

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Carotenoid oxidation products have various structures, among which epoxides and apo- or seco-carotenoids are the two main families. Although both these compound types are widely found in the natural world, the sensitivity of carotenoids to oxidation means they can also be an unwanted presence in in vitro assays. On the other hand, carotenoid oxidation products have also provided chemists with useful chemical tools for the structural identification of carotenoids, and in the natural world they are important biological mediators for plants and animals. In vitro, carotenoid oxidation products have been found to exert various effects which are either potentially beneficial or, on the contrary, detrimental to human health. However, to date, few carotenoid oxidation products have been found in humans. In order to isolate and characterize carotenoid oxidation products and identify their mechanism of formation, we set up two chemical oxidation systems. Lycopene was oxidized with potassium permanganate in a biphasic system to produce the fullest possible range of apo-lycopenals and some diapocarotene-dials. Biomimetic chemical systems of a heminic enzyme center were shown to oxidize lycopene and β-carotene into different families of molecules. Analysis by high-performance liquid chromatography coupled with a diode array-UV/vis detector and a mass spectrometry detector (HPLC-DAD-MS) was used to gain insight into the possible mechanisms of formation of the carotenoid oxidation products formed by these biomimetic systems.

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El-Nakhel, Christophe, Antonio Pannico, Giulia Graziani, Marios C. Kyriacou, Anna Gaspari, Alberto Ritieni, Stefania De Pascale e Youssef Rouphael. "Nutrient Supplementation Configures the Bioactive Profile and Production Characteristics of Three Brassica L. Microgreens Species Grown in Peat-Based Media". Agronomy 11, n.º 2 (15 de fevereiro de 2021): 346. http://dx.doi.org/10.3390/agronomy11020346.

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Brassica L. microgreens are a fresh microscale vegetable crop of high antioxidant value and naturally dense in nutrients without the intervention of biofortification or genetic engineering. A climate chamber experiment on peat-based substrate was set up to test microgreens growth and accumulation of secondary metabolites in response to nutrient supplementation. Microgreens mineral content was analyzed through ion chromatography and total ascorbic acid through UV-Vis spectrophotometry, while carotenoids and phenolic acids were quantified by HPLC-DAD and UHPLC-HRMS, respectively. Brussels sprouts and cabbage yield was only reduced by 10%, while nitrate was reduced by 99% in the absence of nutrient supplementation. Rocket yield was prominently reduced by 47%, with a corresponding nitrate reduction of 118%. Brussels sprouts secondary metabolites were not improved by the absence of nutrient supplementation, whereas cabbage microgreens demonstrated a 30% increase in total ascorbic acid and a 12% increase in total anthocyanins. As for rocket, the absence of nutrient supplementation elicited an extensive increase in secondary metabolites, such as lutein (110%), β-carotene (30%), total ascorbic acid (58%) and total anthocyanins (20%), but caused a decrease in total phenolic acids. It is hereby demonstrated that growing microgreens on a commercial peat-based substrate without nutrient supplementation can be feasible for certain species. Moreover, it might elicit a species-dependent spike in bioactive secondary metabolites.

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Miranda Ordilena Ferreira de, Almeida Marcílio de, Sousa Ilza Maria de Oliveira, Ruiz Ana Lúcia Tasca Gois, Costa José Luiz da, Medeiros Raquel da Silva e Foglio Mary Ann. "Assessment of environmental condition and drying process of the plants on the concentration of alkaloids and cytotoxicity of traditional Ayahuasca Tea". World Journal of Advanced Research and Reviews 10, n.º 2 (30 de maio de 2021): 075–89. http://dx.doi.org/10.30574/wjarr.2021.10.2.0209.

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Introduction: Ayahuasca is a traditional psychoactive tea of Amazonian indigenous, used medicinal and spiritual purposes. Wide variation in the concentration of N,N-dimethyltryptamine (DMT), Harmaline (HRL), Harmine (HRM) and Tetrahydroharmine (THH) alkaloids in Ayahuasca has been reported worldwide. Objective: To evaluate the causes of variations in alkaloids concentrations of Ayahuasca prepared with fresh and dehydrated plants from different environments and determine the best drying method to plants according to alkaloids content and cytotoxicity of Ayahuasca tea. Material and methods: The environment interference on the alkaloids of the two species was evaluated in samples of Ayahuasca tea prepared with fresh plants. The most suitable drying process to the two species was evaluated in sample Ayahuasca tea prepared with plants submitted to drying under the sun conditions and five different temperatures in forced circulation oven. The concentration of the alkaloids determined by high performance liquid chromatography with UV-vis detector with diode array detection (HPLC-DAD). The in vitro cytotoxicity of Ayahuasca was evaluated in human keratinocytes cells (HaCaT) by colorimetric assay. Results: Environmental characteristics, preparation process and temperature of plants drying interfered on DMT, HRL, HRM and THH concentrations of Ayahuasca. No effect cytotoxicity was detected with relationship to psychoactive alkaloids in samples of Ayahuasca tea prepared with fresh or dried plants. Conclusion: Concentration of DMT, HRL, HRM and THH alkaloids in Ayahuasca are influenced by plants environmental. The most suitable drying process was obtained in forced circulation oven at 43 and 45°C to P. viridis leaves and B. caapi stems respectively. The Ayahuasca prepared with fresh or dry plants no showed cytotoxicity in human keratinocytes cells.

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Escott, Carlos, Carmen López, Iris Loira, Carmen González, María Antonia Bañuelos, Wendu Tesfaye, José Antonio Suárez-Lepe e Antonio Morata. "Improvement of Must Fermentation from Late Harvest cv. Tempranillo Grapes Treated with Pulsed Light". Foods 10, n.º 6 (18 de junho de 2021): 1416. http://dx.doi.org/10.3390/foods10061416.

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Pulsed light irradiation is a nonthermal technology currently used for the elimination of pathogens from a diverse range of food products. In the last two decades, the results obtained using PL at laboratory scale are encouraging wine experts to use it in the winemaking industry. PL can reduce native yeast counts significantly, which facilitates the use of starter cultures, reducing SO2 requirements at the same time. In this experimental set up, Tempranillo grapes were subjected to pulsed light treatment, and the fermentative performance of non-Saccharomyces yeasts belonging to the species Schizosaccharomyces pombe, Lachancea thermotolerans, Torulaspora delbrueckii, Metschnikowia pulcherrima and Hanseniaspora vineae was monitored in sequential fermentations against spontaneous fermentation and pure culture fermentation with the species Saccharomyces cerevisiae. The experimental analyses comprised the determination of anthocyanin (High performance liquid chromatography with photodiode array detector—HPLC-DAD), polyphenol index and colour (Ultraviolet-visible spectroscopy—UV-Vis spectrophotometer), fermentation-derived volatiles (Gas chromatography with flame ionization detector—GC-FID), oenological parameters (Fourier transform Infrared spectroscopy—FT-IR) and structural damage of the skin (atomic force microscopy—AFM). The results showed a decrease of 1.2 log CFU/mL yeast counts after pulsed light treatment and more rapid and controlled fermentation kinetics in musts from treated grapes than in untreated samples. The fermentations done with treated grapes allowed starter cultures to better implant in the must, although a larger anthocyanin loss (up to 93%) and an increase in hue values (1 unit) towards more yellow hues were observed for treated grapes. The development of biomass was larger in musts from treated grapes. The profile of volatile compounds and oenological parameters reveals that fermentations carried out with untreated grapes are prone to deviations from native microbiota (e.g., production of lactic acid). Finally, no severe damage on the skin was observed with the AFM on treated grapes.

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Oliveira, Alice R., Lilia B. Caland, Edilene G. Oliveira, Eryvaldo S. T. Egito, Matheus F. F. Pedrosa e Arnóbio A. Silva Júnior. "HPLC-DAD and UV-Vis Spectrophotometric Methods for Methotrexate Assay in Different Biodegradable Microparticles". Journal of the Brazilian Chemical Society, 2015. http://dx.doi.org/10.5935/0103-5053.20150022.

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Williams, David J., David Edwards, Mridusmita Chaliha e Yasmina Sultanbawa. "Measuring free ellagic acid: influence of extraction conditions on recovery by studying solubility and UV-Visible spectra". Chemical Papers 70, n.º 8 (1 de janeiro de 2016). http://dx.doi.org/10.1515/chempap-2016-0038.

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AbstractRecent investigations into plant tissues have indicated that the free form of the natural polyphenolic antioxidant, ellagic acid (EA), is much more plentiful than first envisaged; consequently a re-assessment of solvent systems for the extraction of this water-insoluble form is needed. As EA solubility and its UV-Vis spectrum, commonly used for detection and quantification, are both governed by pH, an understanding of this dependence is vital if accurate EA measurements are to be achieved. After evaluating the pH effects on the solubility and UV-Vis spectra of commercial EA, an extraction protocol was devised that promoted similar pH conditions for both standard solutions and plant tissue extracts. The extraction so devised followed by HPLC with photodiode-array detection (DAD) provided a simple, sensitive and validated methodology that determined free EA in a variety of plant extracts. The use of 100 % methanol or a triethanolamine-based mixture as the standard dissolving solvents were the best choices, while these higher pH-generating solvents were more efficient in extracting EA from the plants tested with the final choice allied to the plants’ natural acidity. Two of the native Australian plants anise myrtle (

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Rubio, Laura, Juan Pablo Lamas, Carmen García-Jares e Marta Lores. "Actividade Antioxidante en Carne de Tenreiros Alimentados con Bagazo de Uva". Recursos Rurais, n.º 14 (1 de fevereiro de 2019). http://dx.doi.org/10.15304/rr.id5779.

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Os subprodutos de elaboración do viño conteñen valiosos compostos bioactivos, entre os que destacan os polifenois. Os efectos beneficiosos destes compostos atribúense, entre outras, á súa actividade antioxidante. Por esta razón, estúdase o efecto potencial dunha dieta enriquecida en polifenois nas características da carne de tenreiros alimentados con bagazo de uva como complemento ou suplemento na súa alimentación. Proponse unha extracción rápida de seis polifenois individuais de carne crúa de tenreiro, previamente identificados e seleccionados como marcadores no bagazo. O procedemento baséase na extracción simultánea automatizada mediante líquidos presurizados (PLE) seguida de cromatografía líquida de alta eficacia con detección UV-Vis cun sistema de díodos (HPLC-DAD) para a identificación dos polifenois e a análise cuantitativo. Nos extractos obtidos determínanse o índice de polifenois totais (IPT) e a actividade antioxidante (AA). Debido á complexidade da mostra, os resultados máis sobresaíntes deste traballo son os relacionados coa avaliación da actividade antioxidante dos extractos. Tras a correspondente análise estatística do conxunto de datos obtidos, pode observarse que resulta mellor incluír unha combinación de bagazo na dieta dos animais dada a mellora observada nos índices antioxidantes medidos, e en consecuencia, tamén nas propiedades da carne e na súa conservación.

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Kostić, Vesna, Trajče Stafilov e Kiro Stojanoski. "HPLC INVESTIGATION OF THE DEGRADATION OF SOME ARTIFICIAL AZO FOOD COLORANTS IN THE PRESENCE OF ASCORBIC ACID". Contributions, Section of Natural, Mathematical and Biotechnical Sciences 29, n.º 1-2 (8 de março de 2017). http://dx.doi.org/10.20903/csnmbs.masa.2008.29.1-2.15.

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A b s t r a c t: The influence of the concentration of ascorbic acid on some azo food colorant (Brilliant Black BN, Brilliant Blue FCF, Chinoline Yellow, Indigotine, Patent Blue V and Tartazine) degradation in the solution has been studied. Rate constant (k), time of colorant half-life (t1/2), as well as the type of the kinetic reaction have been determined. The colorants and the ascorbic acid have been determined by high performance liquid chromatography (HPLC) with diode array detector (DAD) and UV-VIS spectrometry. It was found that the higher concentration of ascorbic acid leads to the higher rate constant and lower colorants half-life. The values of the rate constants are 2.50–4.25 times higher when the colorant degradation was run in the presence of 500 mg L–1 of ascorbic acid than in the case of the presence of 100 mg L–1 ascorbic acid for Brilliant Blue FCF, Chinoline Yellow, Patent Blue V and Tartazine. From the other side, the degradation of Brilliant Black BN and Indigotine is very fast with a total degradation for 6–9 days. Therefore, the rate constants for those two food colorants are much higher than for the other investigated colorants. According to the linearity of the kinetics curves (ln(c/co) v.s. time) it appeared to be first order kinetics for the interval up to 4 days.

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Silva-Silva, João Victor, Carla Junqueira Moragas-Tellis, Maria do Socorro dos Santos Chagas, Paulo Victor Ramos de Souza, Celeste da Silva Freitas de Souza, Daiana de Jesus Hardoim, Noemi Nosomi Taniwaki et al. "Antileishmanial Activity of Flavones-Rich Fraction From Arrabidaea chica Verlot (Bignoniaceae)". Frontiers in Pharmacology 12 (20 de julho de 2021). http://dx.doi.org/10.3389/fphar.2021.703985.

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Acknowledging the need of identifying new compounds for the treatment of leishmaniasis, this study aimed to evaluate, from in vitro trials, the activity of flavones from Arrabidaea chica against L. amazonensis. The chromatographic profiles of the hydroethanolic extract and a flavone-rich fraction (ACFF) from A. chica were determined by high-performance liquid chromatography coupled with a diode-array UV-Vis detector (HPLC-DAD-UV) and electrospray ionization mass spectrometry in tandem (LC-ESI-MS-MS). The flavones luteolin (1) and apigenin (2), isolated from chromatographic techniques and identified by Nuclear Magnetic Resonance of 1H and 13C, were also quantified in ACFF, showing 190.7 mg/g and apigenin 12.4 mg/g, respectively. The other flavones were identified by comparing their spectroscopic data with those of the literature. The in vitro activity was assayed against promastigotes and intramacrophagic amastigote forms of L. amazonensis. Cytotoxicity tests were performed with peritoneal macrophages of BALB/c mice. Nitrite quantification was performed with Griess reagent. Ultrastructural investigations were obtained by transmission electron microscopy. Anti-Leishmania assays indicated that the IC50 values for ACFF, apigenin, and luteolin were obtained at 40.42 ± 0.10 and 31.51 ± 1.13 μg/mL against promastigotes, respectively. ACFF and luteolin have concentration-dependent cytotoxicity. ACFF and luteolin also inhibited the intra-macrophagic parasite (IC50 3.575 ± 1.13 and 11.78 ± 1.24 μg/mL, respectively), with a selectivity index of 11.44 for ACFF. Promastigotes exposed to ACFF and luteolin exhibited ultrastructural changes, such as intense cytoplasm vacuolization and mitochondrial swelling. These findings data evidence the antileishmanial action of flavone-rich fractions of A. chica against L. amazonensis, encouraging further studies.

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Aires, Alfredo, Carla Dias, Rosa Carvalho e Maria José Saavedra. "Analysis of glycosylated flavonoids extracted from sweet-cherry stems, as antibacterial agents against pathogenic Escherichia coli isolates". Acta Biochimica Polonica 64, n.º 2 (11 de julho de 2017). http://dx.doi.org/10.18388/abp.2016_1374.

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The aim of this study was to evaluate the bioactivity of flavonoids extracted from sweet-cherry stems, which is often used by traditional medicine to treat infections from gastro-intestinal and urinary but without any consistent scientific evidences, moreover the information about the class of phenolics, their content and the potential bioactivity of such material is very scarce. Thus, in this context, we set a research study in which we evaluate the profile and content of phenolics extracted from sweet-cherry stems through a conventional (70ºC and 20 minutes) and ultrasound assisted extraction (40 kHz, room temperature and 20 minutes) methods. After, the extracts were phytochemical characterized by HPLC-DAD-UV/VIS, and assayed trough the in vitro minimum inhibitory concentration (MIC) bioassay, against Escherichia coli isolates. Simultaneously the total antioxidant activity were measured using the assay of 2,2′-azinobis-3-ethylbenzothiazoline-6-sulphonate (ABTS●+) radical cation. Our results showed that sweet-cherry stems presented higher content of sakuranetin, ferulic acid, p-coumaric acid, p-coumaroylquinic acid, chlorogenic acid and it´s isomer neochlorogenic acid. Their average levels were highly affected by the extraction method (p<0.001) used. The same trend was observed for total antioxidant activity and MIC values. The extracts produced under ultrasound presented both higher total antioxidant activity and lower minimum inhibitory concentration. The statistical analyses of our results showed a significant correlation (p<0.01) of total antioxidant activity and minimum inhibitory concentration with phenolics in the extracts studied. Thus, we can conclude that cherry stems can be further exploited to purify compounds and produced coproducts with enhanced biological added valuefor pharmaceutical industry.

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Wang, Chun-Ru, Chun-Li Bai e Hisanori Shinohara. "Novel Structure of Fullerenes and Endohedral Fullerenes". MRS Proceedings 775 (2003). http://dx.doi.org/10.1557/proc-775-p10.3.

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AbstractBy using Krätschmer-Huffman synthesis and HPLC separation method we have isolated a series of novel fullerenes and endohedral fullerenes. Various spectroscopic techniques, e.g., MS, NMR, UV-vis-NIR, TEM, X-ray diffraction spectrometry etc., were adopted to characterize the isolated fullerenes. Several fullerenes were revealed to hold novel structures and electronic properties. For examples, C80(D5d) was isolated and characterized to have an ellipsoidal structure which is in fact one of the shortest SW-nanotubes; The isolation of Sc2@C66 breaks the well-known isolated-pentagon-rule (IPR) for the first time, which shows that the unconventional fullerenes may be dramatically stabilized through encaging metal atoms; Sc2C2@C84 is a novel molecular endohedral fullerene in which the Sc2C2 cluster rotates rapidly along the main C2 axis of C84(D2d). This fullerene is predicted to be a molecular magnet and may be used as nano-switcher in electronics.

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