Academic literature on the topic 'Free radicals; Antioxidants'
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Journal articles on the topic "Free radicals; Antioxidants"
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Kanter, Mitchell M. "Free Radicals, Exercise, and Antioxidant Supplementation." International Journal of Sport Nutrition 4, no. 3 (September 1994): 205–20. http://dx.doi.org/10.1123/ijsn.4.3.205.
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Free radicals have been implicated in the development of diverse diseases such as cancer, diabetes, and cataracts, and recent epidemic-logical data suggest an inverse relationship between antioxidant intake and cardiovascular disease risk. Data also suggest that antioxidants may delay aging, Research has indicated that free radical production and subsequent lipid peroxidation are normal sequelae to the rise in oxygen consumption with exercise. Consequently, antioxidant supplementation may detoxify the peroxides produced during exercise and diminish muscle damage and soreness. Vitamin E, beta carotene, and vitamin C have shown promise as protective antioxidants. Other ingestible products with antioxidant properties include selenium and coenzyme. The role (if any) that free radicals play in the development of exercise-induced tissue damage, or the protective role that antioxidants may play, remains to be elucidated. Current methods used to assess exercise-induced lipid peroxidation are not extremely specific or sensitive; research that utilizes more sophisticated methodologies should help to answer many questions regarding dietary antioxidants.
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Bisht, Rekha. "Antioxidants: a brief review." Journal of Drug Delivery and Therapeutics 8, no. 6-s (December 15, 2018): 373–76. http://dx.doi.org/10.22270/jddt.v8i6-s.2116.
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The field of free radical chemistry has gained a great deal of attention in recent years. Free radicals reactive oxygen species generated by our body by various endogenous systems leads to various pathological conditions. A balance between free radicals and antioxidants is prerequisite for proper physiological function. Oxidative stress caused by generation of free radicals adversely alters lipids, proteins, and DNA and provokes a number of human ailments. Oxidative stress can be managed by using external sources of antioxidants. Synthetic antioxidants such as butylated hydroxytoluene and butylated hydroxyanisole have recently been reported to be harmful for human health. Thus, the search for effective, nontoxic natural compounds with antioxidant activity has been escalated in recent years. The present review provides a brief overview on antioxidants and natural sources of antioxidants in the management of human diseases.
Keywords: free radical, Oxidative stress, antioxidants,
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Dwimayasanti, Rany. "RUMPUT LAUT: ANTIOKSIDAN ALAMI PENANGKAL RADIKAL BEBAS." OSEANA 43, no. 2 (October 30, 2018): 13–23. http://dx.doi.org/10.14203/oseana.2018.vol.43no.2.17.
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SEAWEED: NATURAL ANTIOXIDANT FREE RADICAL ANTIDOTE. Free radicals are the result of various complex chemical processes in the body, in form of oxidation process, cell metabolism, UV irradiation, environmental pollution such as cigarette smoke, and other pollutants. The effects of free radicals can be prevented by addition of antioxidants endogenously from outside the body. Seaweed is one source of natural antioxidants that is safe for the body. Seaweed contains bioactive compounds that are able to prevent free radicals such as carotenoids, phenols, vitamins and minerals.
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Noor, Rana, Fatema Sayeed, Rizwana Mallick, Eram Perwez, and Shabina Sachdeva. "Effect of Free Radicals and Antioxidants in Periodontal Disease." Indian Journal of Dental Education 9, no. 3 (2016): 165–69. http://dx.doi.org/10.21088/ijde.0974.6099.9316.4.
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NEUBAUER, R. "Free radicals and antioxidants." Lancet 344, no. 8934 (November 1994): 1440–42. http://dx.doi.org/10.1016/s0140-6736(94)90612-2.
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Xu, Qing, Tian Zhong, and Hui Li Li. "Antioxidant and Free Radical Scavenging Activities of N-Modified Chitosans." Advanced Materials Research 1002 (August 2014): 91–98. http://dx.doi.org/10.4028/www.scientific.net/amr.1002.91.
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Recently, the search for effective natural antioxidants use in food and medicinal fields to replace synthetic ones has attracted the most attention. Chitosan, a natural nontoxic biopolymer, is known to possess antioxidant property, which is attributed that NH2 and OH attached in the pyranose ring react with unstable free radicals to form stable macromolecule radicals. It has been observed that the antioxidant activity of chitosan is closely related to the form of nitrogen atom in the molecules. This review focuses on the antioxidant and free radical scavenging activities of various nitrogen atom of chitosan, including N-acylated chitosans, Schiff bases of chitosan, N-alkyl chitosan, and N-quaternized chitosan. The free radical scavenging mechanisms are summarized and the effects on free radical scavenging activity of N-modified chitosan are discussed. This work may provide more insights into the antioxidant ability of N-modified chitosans and potentially enable them to be used as natural antioxidants for application in food, agriculture, cosmetic and biomedical science. Keywords: N-modified chitosan, Sythesis, Antioxidant, Free radical scavenging
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G, Savitha, Vishnupriya V, and Surapaneni Krishnamohan. "IN VITRO ANTIOXIDANT CAPACITY AND FREE RADICAL SCAVENGING ACTIVITIES OF CARDIOSPERMUM HALICACABUM LINN." Asian Journal of Pharmaceutical and Clinical Research 11, no. 7 (July 7, 2018): 421. http://dx.doi.org/10.22159/ajpcr.2018.v11i7.25044.
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Objective: Free radicals and oxidants are produced in the body during normal cellular metabolism and exposure to pollutions and ionizing radiations. They exert beneficial and harmful effects to the human body. Harmful effects of these radicals are destroyed by either antioxidants of our body in situ or antioxidants which are supplied through foods. Hence, the aim of this present study is to assess the antioxidant and free radical scavenging capacity of the easily available edible plant Cardiospermum halicacabum Linn. (Mudakathan keerai).Methods: Antioxidant and free radical scavenging activities of the aerial parts extract of C. halicacabum was determined by 2,2-diphenyl-1- picrylhydrazyl (DPPH) radical scavenging assay, 2,2-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) (ABTS) radical scavenging assay, ferrous ion chelating assay, nitric oxide (NO) radical scavenging assay, superoxide radical scavenging assay, hydroxyl radical scavenging assay, and lipid peroxidation assay.Results: Remarkable free radical scavenging potential was observed in the ethanolic extract of C. halicacabum with IC50 values on all tested radicals, namely DPPH (IC50=34.06 μg/ml), ABTS (IC50=21.45 μg/ml), ferrous ion chelating (IC50=19.56 μg/ml), NO (IC50=25.16 μg/ml), superoxide (IC50=35.16 μg/ml), hydroxyl (IC50=28.56 μg/ml), and lipid peroxidation (IC50=33.12 μg/ml). The results revealed that ethanolic extract of C. halicacabum Linn. has significant antioxidant activity.Conclusion: The present study suggested that the aerial part extract of C. halicacabum serves as a good source of natural antioxidants.
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Qiu, Song Shan, Zhi Hui Wang, and Cui Cui Jiang. "Free-Radical Scavenging Capacity of Sasanquasaponin from Camellia Oleifera Abel." Advanced Materials Research 236-238 (May 2011): 2367–70. http://dx.doi.org/10.4028/www.scientific.net/amr.236-238.2367.
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In this study, the antioxidant activity of sasanquasaponin fromCamellia oleifera Abel.was determined by various antioxidant assays. The results of reducing power of sample indicated sasanquasaponin were electron donors and could react with free radicals to convert them into more stable products, terminating the radical chain reactions.The results indicated that sasanquasaponin can clear active oxygen radicals producing in the chemical reactions and have stronger antioxidant ability. Therefore they could be used as natural antioxidant that are stable at high temperatures and can serve as substitutes for synthetic antioxidants.
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Buehler, Bruce A. "The Free Radical Theory of Aging and Antioxidant Supplements." Journal of Evidence-Based Complementary & Alternative Medicine 17, no. 3 (April 11, 2012): 218–20. http://dx.doi.org/10.1177/2156587212441939.
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Free radical excess occurs when cells are exposed to reactive oxygen species greater than the amount that can be neutralized by cellular produced antioxidants such as superoxide dismutase. This is termed oxidative stress, which can be caused by excessive energy intake or external pollutants. Excess free radicals are proposed to increase the rate of cell aging, injury, and mutations leading to a shortened cell life span. Vitamins A, C, and E and flavoproteins are supplements that function as free radical scavengers. Antioxidants are present in natural foods but added amounts beyond the diet may detoxify excess free radicals during “oxidative stress.” Antioxidant supplements decrease cellular damage from excess reactive oxygen species but they have not been proven to prolong life span.
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Gautam, Narayan. "Free radicals and vitamin antioxidants in health and lung diseases." Journal of Universal College of Medical Sciences 3, no. 3 (December 31, 2015): 43–52. http://dx.doi.org/10.3126/jucms.v3i3.24249.
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Several lung diseases have undergone oxidative stress due to free radical insult. Consequently, antioxidant vitamin C and vitamin E play important role in defense against cellular injury by scavenging free radicals. This article reviews the potential mechanism of free radicals generation and vitamin antioxidant defense to link amongst various lung diseases. One of the manifestations of free radical mediated process is lipid peroxidation subsequently producing malondialdehyde (MDA) in these patients. Supplementation of vitamin C and vitamin E as an adjuvant therapy as well as high intake of fresh fruits and vegetables appear to have a beneficial effect on lung health. Moreover, their consumption should be recommended on a daily basis. Further studies are needed to assess the impact of antioxidants as an adjuvant therapy in patients with lung diseases.
Dissertations / Theses on the topic "Free radicals; Antioxidants"
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Araujo, Deborah de Arantes e. Oliveira Valim 1972. "Avaliação da gastroproteção do óleo essencial do Protium heptaphyllum March (Burceraceae) bem como os possíveis mecanismos de ação envolvidos em modelos de úlcera gástrica em ratos : Evaluation of gastroprotection essential oil Protium heptaphyllum March (Burceraceae) and the possible mechanisms involved on experimental gastric ulcer models in rats." [s.n.], 2012. http://repositorio.unicamp.br/jspui/handle/REPOSIP/313745.
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Orientadores: Alba Regina Monteiro Souza Brito, Anderson Luiz FerreiraDissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Ciências Médicas
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Resumo: Protium heptaphyllum March (Burseraceae), conhecido como almécega ou breu branco, é uma planta medicinal abundante na região Amazônica. Seu exudato resinoso in natura é um conceituado remédio popular com ação anti-inflamatória, antiulcerogênica, analgésica e cicatrizante. O gênero Protium compreende cerca de 135 espécies, estima-se que a maioria das espécies da família Burseraceae pertençam a este gênero, tendo como principal característica sua capacidade em exsudar resinas aromáticas voláteis, usadas como curativo de feridas, tratamento de dor de dente, antisséptico, analgésico e distúrbios gastrointestinais. O objetivo deste trabalho, foi avaliar o potencial gastroprotetor do óleo essencial comercial do Protium heptaphyllum March (Burseraceae) (BB), bem como os possíveis mecanismos de ação envolvidos, através de modelos de úlcera gástrica em ratos Unib:WH. A análise de cromatografia gasosa-espectrometria de massa (CG-EM) do BB indicou a presença de três monoterpenos majoritários: ?-pineno (40%), p-mentha-1.4(8)-dieno (12%) e ?-phellandreno (10%). Foram realizados diferentes modelos experimentais de úlcera gástrica que, com base em suas respectivas especificações, foram incluídos dois grupos controles, sendo um positivo (Lansoprazol 30 mg/kg, Carbenoxolona 200 mg/kg ou Cimetidina 100 mg/kg) e um negativo (Veículo - Tween 80® 12%, 10 mL/Kg). Após cada experimento, foi realizada eutanásia por deslocamento cervical, os estômagos removidos, abertos na região da maior curvatura e fotografados para quantificação da área de lesão ulcerativa (ALU) por meio do programa AVSoft®. O BB, na dose de 100 mg/Kg (dose mais efetiva), apresentou atividade antiulcerogênica contra lesões gástricas induzidas por etanol absoluto (96%) e por Drogas ant-inflamatórias não esteroidais (DAINEs) (97%). Para avaliar os mecanismos de ação envolvidos a atividade antissecretória, muco, prostaglandina, atividade antioxidante e envolvimento dos Grupamentos Sulfidrila (G-SH), foram analisados. Além disto, o modelo de úlcera gástrica induzida por ácido acético e análise por Western blotting da expressão de COX-2 e EGF foram utilizadas para avaliar a capacidade cicatrizante do BB. Foi verificado que este óleo essencial não interfere na secreção ácida na mucosa gástrica; porém, sua gastroproteção depende de compostos com G-SH. A atividade gastroprotetora do BB não ocorre devido ao aumento na produção de muco induzido pelos níveis gástricos de PGE2. Como o BB não atuou nos mecanismos citoprotetor e antissecretório, objetivou-se verificar o envolvimento do mecanismo antioxidante na atividade gastroprotetora. Existem evidências de que espécies reativas de oxigênio participem na etiologia da úlcera gástrica e muitos óleos essenciais foram recentemente qualificados como antioxidantes naturais. A capacidade do BB de reduzir ou prevenir estresse oxidativo foi avaliada in vivo, a partir de modelos de úlcera induzida por etanol absoluto. O BB apresentou atividade antioxidante modulando enzimas antioxidantes como Superóxido Dismutase (SOD), Glutationa Peroxidase (GSH-Px) e Glutationa Redutase (GSH-Rd), desta forma, diminuindo a peroxidação lipídica (LPO) e atividade da Mieloperoxidase (MPO). BB demonstrou também potente capacidade de cicatrização, com 95% de redução da ALU, aumentando a expressão de COX-2 (55%) e EGF (100%) na mucosa gástrica. Em adição, nenhum sinal de toxicidade foi observado durante os 14 dias de tratamento, considerando os parâmetros analisados. Portanto o BB é composto essencialmente por terpenos, não apresenta atividade antissecretora nem citoprotetora, apresenta atividade antioxidante e cicatrizante
Abstract: Protium heptaphyllum March (Burseraceae), known as "Almécega" or "Breu Branco", a medicinal plant is abundant in the Amazon region, its resinous exudates in nature, is a renowned folk remedy with anti-inflammatory, antiulcer, analgesic and healing. Protium genus comprises about 135 species, it is estimated that most species of Burseraceae, belong to this genus, the main feature, its ability to exude volatile aromatic resins, used for various purposes such as dressing for wounds, pain tooth, antiseptic, analgesic, treatment of stomach, among others. Based on the popular indications of this plant for the treatment of gastrointestinal disturbances, the present work aimed on evaluating the gastroprotective potential of the commercial essential oil of Protium heptaphyllum March (Burseraceae) (BB), as well as its possible mechanisms of action involved, through models of gastric ulcer in rats Unib: WH. Gas chromatography-mass spectrometry (GC-MS) analysis of BB indicated the presence of three majority monoterpenes as major compounds: ?-pinene (40%), p-mentha-1.4(8)-diene (12%) and, ?-phellandreno (10%). We performed different experimental models of gastric ulcer, based on your specifications included two control groups, a positive (Lansoprazole 30 mg/kg, Cimetidine 100 mg/kg or Carbenoxolone 200 mg/kg) and a negative (Vehicle - Tween 80, 12%, 10 mL/Kg). After each experiment, rats were killed by cervical dislocation, their stomachs removed and opened in the region of greater curvature and photographed for quantification of lesion area ulcerative through the AVSoft program. BB at a dose of 100 mg / kg (effective dose) showed antiulcer activity against gastric lesions induced by absolute ethanol (96%) and nonsteroidal ant-inflammatory drugs (NSAIDs) (97%). To evaluate the mechanisms involved in the BB aniulcerogenic activity, the antisecretory action, mucus, prostaglandins, antioxidant activity and involvement of sulfhydryl group (G-SH) were analyzed. The acetic acid-induced gastric ulcer model and western blotting assay COX-2 and EGF were also used to evaluate the BB healing capacity. This essential oil does not interfere with acid secretion in the gastric mucosa, but their gastroproteção depends on G-SH compounds. The gastroprotective activity of the BB is not due to increased production of gastric mucus induced by PGE2 levels. As the BB did not act in cytoprotective mechanisms and antissecretório, aimed to verify the involvement of the antioxidant mechanism in gastroprotective activity. There is evidence that reactive oxygen species involved in the etiology of gastric ulcer and many essential oils have recently been classified as natural antioxidants. The role of the essential oil in reducing or preventing the oxidative stress was evaluated in vivo, from absolute ethanol-induced gastric ulcer model. The BB showed antioxidant activity by modulating antioxidant enzymes like Superoxide Dismutase (SOD), glutathione peroxidase (GSH-Px) and glutathione reductase (GSH-Rd), thereby decreasing lipid peroxidation (LPO) and activity Myeloperoxidase (MPO). The BB has demonstraded potent healing capacity, with 95% reduction of the ulcerative lesion area due to increased expression of COX-2 (55%) and EGF (100%) in the gastric mucosa. In addition, no signs of toxicity were observed during the 14 days of treatment, considering the analyzed parameters. So BB is composed mainly of terpenes, shows no activity antissecretora or cytoprotective, exhibits antioxidant activity and healing
Mestrado
Farmacologia
Mestre em Farmacologia
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Oliveira, Rosiris Sindeaux de Alencar Pires de. "Conceitos alternativos sobre radicais livres: origens, prevalência e intervenções." Universidade de São Paulo, 2016. http://www.teses.usp.br/teses/disponiveis/46/46131/tde-02122016-150646/.
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Este trabalho teve por objetivos: levantar conceitos alternativos sobre radicais livres na mídia impressa e em livros de Bioquímica; examinar os conceitos alternativos prevalentes em pós-graduandos e em professores de Química e Biologia do Ensino Médio; e, planejar e aplicar intervenção para reduzir a influência destes conceitos. Para o levantamento na mídia impressa, foi selecionada a revista Veja, período de 01/01/2000 a 31/07/2014, e foram criadas as seguintes categorias para classificar o material encontrado: Conceito Alternativo (CA), Informação Indutiva (II), Conceito Indutivo (CI) e Generalização Indevida (GI), formando o grupo dos Conceitos Não Científicos (CNC); Conceito Correto (CC); Conceito Errado (CE); e, não preenche os critérios de inclusão (NPCI). Foram encontrados 294 trechos dos quais: 55,4% CA; 21,1% II; 9,2% CI; 5,4% GI; 4,1% CC; 2,7% CE; 2,0% NPCI; e, 91,2% CNC. Para o levantamento em livros de Bioquímica foram selecionados: Campbell - Bioquímica; Lehninger - Princípios de Bioquímica; Marzzoco e Torres Bioquímica Básica; Stryer - Bioquímica; e, Voet e Voet - Bioquímica. A maior parte dos conceitos encontrados nos livros foram conceitos corretos, contudo 77,5% dos conceitos encontrados destacavam aspectos negativos sobre radicais livres. Para o levantamento de conceitos alternativos em pós-graduandos e professores foi desenvolvido o Questionário de Radicais Livres (QRL), versões piloto e final, aplicadas, respectivamente, a 14 pós-graduandos matriculados na disciplina de pós-graduação Planejamento e Aplicação de Sequências Didáticas Envolvendo o Conteúdo Radicais Livres e 31 professores matriculados no curso de extensão Radicais Livres e suas Interfaces com a Vida, planejado com o auxílio dos pós-graduandos da disciplina. O QRL é um questionário de múltipla-escolha em etapas, composto por uma etapa de avaliação do conteúdo e outra sobre a percepção do participante sobre seu nível de certeza. Os pós-graduandos revelaram baixo domínio sobre o tema e baixo nível de certeza. Os professores, testados pré- e pós-intervenção, também apresentaram alta frequência de erros, bastante semelhante no pré- e no pós-teste, e baixo nível de certeza no pré-teste e aumento do nível de certeza no pós-teste. Acredita-se que estes resultados, tanto entre os pós-graduandos e como entre os professores, sejam reflexo da falta de contato acadêmico com o tema. Aos professores, também foram aplicados dois questionários complementares denominados Perfil Profissional e Conhecimentos Sobre Radicais Livres. Entre outras informações, os dados coletados a partir destes questionários, indicaram que os professores lecionam juntos para aproximadamente 12000 estudantes e que o curso de extensão contribuiu para aumentar seus conhecimentos sobre radicais livres. Estes dados oferecem suporte para a escolha do público-alvo e justificam a execução de cursos de extensão, tanto pelo o potencial de alcançar indiretamente um grande número de pessoas, como pela possibilidade de difusão do tema. Tanto o curso de extensão como a disciplina de pós-graduação foram muito bem avaliados pelos professores e pós-graduandos. Os altos percentuais de conceitos não científicos, principalmente conceitos alternativos, encontrados na mídia impressa, bem como os conceitos alternativos apresentados por pós-graduandos e professores, devem preocupar especialistas e cientistas, pois este tema é objeto de muitos anúncios publicitários que frequentemente incentivam o consumo de suplementos de antioxidantes. Em livros de Bioquímica, o aumento de conteúdo destacando o papel fisiológico dos radicais livres deve contribuir para desfazer o conceito disseminado de que radicais livres seriam prejudiciais à saúde.This work aimed to survey the misconceptions regarding free radicals published in printed media and in biochemistry textbooks; to examine the misconceptions regarding free radicals prevalent among graduate students and chemistry and biology high school teachers; and to design and implement instructional intervention to reduce the influence of these misconceptions. For surveying printed media, publications from Veja magazine, dating from 01/01/2000 to 07/31/2014, were selected. The published material was categorized as follows: Misconception (MC), Inductive Information (II), Inductive Concept (IC), and Inadequate Generalization (IG) - collectively called Non-Scientific Concepts (NSC) - and Right Concept (RC), Wrong Concept (WC), and not fit for the inclusion criteria (NFIC). A total of 294 text excerpts were obtained, comprising 55.4% MC, 21.1% II, 9.2% IC, 5.4% IG, 4.1% RC, 2.7% WC, 2.0% NFIC, and 91.2% NSC. In order to examine the content in biochemistry textbooks, the following were selected: Campbell - Biochemistry; Lehninger - Principles of Biochemistry; Marzzoco & Torres - Basic Biochemistry; Stryer - Biochemistry; and Voet & Voet - Biochemistry. Most of the excerpts selected from the biochemistry textbooks were right concepts. However, 77.5% of the concepts highlighted negative aspects of free radicals. To investigate misconceptions among graduate students and high school teachers, a Free Radicals Questionnaire (FRQ) was developed. Pilot and final versions were given to 14 students enrolled in the graduate course Planning and Application of Didactical Sequences Encompassing Free Radicals Content and to 31 high school teachers enrolled in the extension course Free Radicals and its Interfaces with Life, respectively. The extension course was planned with the assistance of graduate students enrolled in the graduate course. FRQ is a multiple choice tier test with tiers for content evaluation and the participants perception of their level of certainty. Graduate students exhibited low levels of subject expertise and certainty. Teachers were tested pre- and post-intervention, and exhibited a high frequency of mistakes, comparable to graduate students, with similar pre- and post-test outcomes. However, their certainty level increased post-test. It is believed that these results may have occurred due to an academic lack of contact with the subject of free radicals. Additionally, two complementary questionnaires were given to the teachers: Professional Profile and Free Radicals Knowledge. Data collected from these questionnaires indicated that teachers collectively taught approximately 12,000 students and that the extension course contributed to increasing the teachers knowledge on free radicals. These results support the choice of the target audience and justify the implementation of the extension courses, because these courses have the potential to indirectly reach a large audience and can be used for thematic dissemination of knowledge in the subject area. The extension and graduate courses were highly rated by the teachers and graduate students, respectively. The high percentage of non-scientific concepts, especially misconceptions, found in printed media, as well as the misconceptions regarding free radicals prevalent among graduate students and teachers must concern specialists and scientists, as this topic is the subject of many advertisements encouraging consumption of antioxidant supplements. In biochemistry textbooks, increasing the content highlighting the physiological role of free radicals would contribute considerably in dispelling the widespread notion that free radicals are harmful to health.
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Ahmed-Choudhury, Jalal. "In vitro effects of tertiary-butylhydroperoxide (tBOOH), an oxidative stress inducer, on the processes involved in bile formation using rat hepatocyte couplets." Thesis, University of Birmingham, 1999. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.367345.
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Vieira, Henrique Heringer 1987. "Influência do tipo de matriz e de um antioxidante experimental na resistência de união entre compósito e estruturas dentais através de microcisalhamento." [s.n.], 2013. http://repositorio.unicamp.br/jspui/handle/REPOSIP/289481.
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Orientadores: José Roberto Lovadino, Débora Alves Nunes Leite LimaDissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Odontologia de Piracicaba
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Resumo: Este trabalho divido em dois estudos teve como objetivos: 1 - Avaliar através de microcisalhamento a influência de três tipos de matrizes para confecção dos cilindros de resina composta sobre a resistência de união a dentina, 2- Avaliar a aplicação de um agente antioxidante experimental, antes e durante o procedimento adesivo, sobre a resistência de união aos substratos dentais clareados. Todas as amostras foram feitas com adesivo simplificado convencional (Single Bond / 3M ESPE) e resina fluida de nanopartículas (Filtek Z 350 Flow / 3M ESPE). Para o estudo 1 vinte dentes bovinos foram cortados, lixados e planificados, a fim de expor a dentina coronária. Em cada fragmento dental foram confeccionados três cilindros, cada feito com um tipo diferente de matriz: 1 - matriz de silicone, 2 - matriz experimental de macarrão e 3 - matriz de Tygon. A remoção dos tipos 1 e 3 de matrizes se fez pelo corte da matriz, e do tipo 2 por imersão em água até que o macarrão se soltasse do espécime. As amostras foram submetidas ao microcisalhamento. Os dados foram analisados através de análise unidirecional de variância (ANOVA) (? = 0,05). Não houve diferença estatística entre os diferentes tipos de matrizes estudadas. Para o estudo 2 foram utilizados 100 fragmentos de dentes bovinos, medindo 6x6x1mm de espessura. Os fragmentos foram distribuídos em 10 grupos, variando o substrato dental (esmalte e dentina) e tratamento a ser realizado: controle (sem tratamento), clareamento (peróxido de hidrogênio 35%) sem aplicação do agente antioxidante, clareamento com aplicação do agente antioxidante por 10 minutos antes do procedimento restaurador, clareamento com aplicação do agente antioxidante por 10 minutos após o condicionamento ácido, clareamento com aplicação do agente antioxidante por 30 minutos antes do condicionamento ácido. Após um período de 24 horas armazenado em saliva, os corpos de prova foram submetidos ao teste de microcisalhamento. Então foi aplicada análise de variância (ANOVA) "1 way" e teste de Tukey, considerando o nível de significância 5%, e análise do padrão de fratura. Não foi encontrada diferença estatística na resistência de união para o esmalte. Em dentina os grupos que receberam tratamento com antioxidante apresentaram valores de resistência de união intermediários aos grupos controle e sem tratamento antioxidante. Pode-se concluir que o tipo de matriz não interferiu nos resultados de resistência de união a dentina, e que o agente antioxidante apresentou bom comportamento por elevar os valores de resistência de união à dentina clareada
Abstract: This work divided in two studies aimed to: 1 - Evaluate through microshear the influence of three types of matrices for the fabrication of composite resin cylinders on the bond strength to dentin; 2 - Evaluate the application of an experimental antioxidant, before and during the adhesive procedure on the bond strength to dental substrates bleached. All samples were made with conventional simplified adhesive (Single Bond / 3M ESPE) and nanoparticles flow composite (Filtek Z 350 Flow / 3M ESPE). For the first study twenty bovine incisors were cuted, grinded and planned in order to expose coronal dentin. Each dental fragment received three cylinders, each one made with a different type of matrix: 1 - silicone matrix, 2 - experimental matrix and 3 - Tygon matrix. Removal of the 1 and 3 matrix types were made by cutting the matrix, and type 2 by immersion in water until the noodle let out of the specimen. Samples were so subjected to microshear. Data were analyzed using one-way analysis of variance (ANOVA) and Tukey's test (? = 0.05). There was no statistical difference between the matrices studied. For study 2 one hundred fragments of bovine incisors were used, measuring 6x6 mm and height of enamel and dentin 1mm each. The fragments were distributed into 10 groups, varying the dental substrate (enamel and dentin) and treatment to be performed: Control (no treatment), bleaching (hydrogen peroxide 35%) without application of antioxidant, bleaching agent application antioxidant for 10 minutes before the restorative procedure, bleaching with agent application antioxidant for 10 minutes after the acid etching, bleaching with agent application antioxidant for 30 minutes before etching. After a period of 24 hours stored in saliva, the samples passed by microshear test. So was applied one way ANOVA, considered the 5% significance level, and analysis of the fracture pattern. There was no statistical difference in enamel. In dentin the groups that received treatment with antioxidant, showed intermediate values compared with untreated and control groups. Can be concluded that the type of matrix does not affect the results of bond strength to dentin, and that the antioxidant showed good behavior by raising the values of bond strength to bleached dentin
Mestrado
Dentística
Mestre em Clínica Odontológica
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Ishimoto, Emilia Yasuko. "Efeito hipolipemiante e antioxidante de subprodutos da uva em hamsters." Universidade de São Paulo, 2008. http://www.teses.usp.br/teses/disponiveis/6/6133/tde-23072010-114923/.
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Introdução: Recentes pesquisas têm indicado o enorme potencial de certas substâncias alimentares, como polifenóis antioxidantes e fibras na redução de riscos de doenças crônicas. O bagaço de uva, subproduto do processamento de vinhos e sucos, representa uma ótima fonte de fibras e antioxidantes naturais de baixo custo. Objetivo: Avaliar o potencial hipolipemiante, antioxidante e sensorial de subprodutos do processamento do vinho e do suco. Métodos: Para avaliar a capacidade antioxidante in vitro, foi utilizado o método do DPPH. O potencial antioxidante e hipolipemiante in vivo foi avaliado mediante ensaio biológico, no qual sessenta hamsters foram divididos em seis grupos diferenciados pelas dietas: controle, hiperlipemiante, extrato de bagaço do vinho (BV), extrato de bagaço do suco (BS), suplementada com BV e suplementada com BS. Amostras de sangue e fígado foram coletadas após 4 semanas de experimento para avaliação do perfil lipídico, capacidade de inibição da oxidação de LDL-colesterol (LDL-c) e atividade das enzimas antioxidantes superóxido dismutase (SOD), catalase (CAT) e glutationa peroxidase (GPx). Para a avaliação sensorial, foram desenvolvidos sorbet e picolé de BV e BS, cujos atributos sensoriais foram avaliados por 43 pessoas aplicando-se o método afetivo de escala hedônica de 9 pontos. Resultados: Extratos de BV e BS apresentaram uma expressiva capacidade antioxidante in vitro. No modelo animal, os grupos tratados com BV e BS apresentaram uma melhora significativa do perfil lipídico e da atividade da enzima CAT, em relação aos grupos controle e hipercolesterolêmico (p<0,05). Com relação aos valores de SOD, GPx e inibição da oxidação de LDL-c, observou-se melhores resultados em relação ao grupo hipercolesterolêmico, embora não significativamente em todos os grupos tratados. Na análise sensorial, somente o picolé de BV não preencheu totalmente os requisitos de aceitação. Conclusão: Os subprodutos de ambas as espécies de uva apresentaram potencial biológico e sensorial para serem utilizados como ingredientes funcionais.Introduction: Recent studies have shown the great potential of certain food components such as antioxidant polyphenols and fiber in reducing the risk of chronic diseases. Grape pomace, a wine and juice processing byproduct, is a low cost material and a very good source of fiber and natural antioxidants. Objectives: To evaluate the hypolipidemic, antioxidant and sensory potential of wine and grape byproducts. Methods: To evaluate the in vitro antioxidant capacity, the DPPH method was used. The in vivo antioxidant and hypolipidemic potential was evaluated through an animal model, in which sixty hamsters were divided into six groups according to their diets: control, hyperlipidemic, wine pomace (WP) extract, juice pomace (JP) extract, WP supplemented diet and JP supplemented diet. Samples of blood and liver were collected after a 4-week experimental period to evaluate the lipid profile, ability to inhibit the LDL-cholesterol (LDL-c) oxidation and antioxidant activity of superoxide dismutase (SOD), catalase (CAT) and glutathione peroxidase (GPx) enzymes. For the sensory evaluation, BV and BS sorbet and popsicle were developed, and the sensory attributes were evaluated by 43 tasters according to a 9- point affective hedonic scale. Results: WP and JP extracts showed a very good in vitro antioxidant capacity. In the animal model, both WP and JP treated groups presented a significant improvement in the lipid profile and CAT enzyme antioxidant activity in comparison to hypercholesterolemic and control groups (p <0.05). Regarding the values of SOD, GPx and inhibition of LDL-c oxidation, there values were better when compared to hypercholesterolemic group, even though they were not significant in all treated groups. In the sensory evaluation, only the BV popsicle was not fully accepted. Conclusion: Both grapes byproducts showed a biological and sensory potential to be used as functional ingredients.
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Nichi, Marcilio. "Efeito do tratamento com antioxidantes e ácidos graxos poli-insaturados em amostras espermáticas epididimárias de touros." Universidade de São Paulo, 2009. http://www.teses.usp.br/teses/disponiveis/10/10131/tde-18012010-095928/.
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Amostras espermáticas provenientes do epidídimo podem ser utilizadas com diversas finalidades tais como: modelo experimental para pesquisa com sêmen, aproveitamento do sêmen de animais de alto valor genético que vierem a óbito e possibilidade da coleta e aproveitamento do sêmen de animais em perigo de extinção. No entanto, para a utilização desta técnica é necessário o estudo de diversos fatores que poderiam influenciar sua eficiência, como por exemplo, as formas de armazenamento dos testículos, efeitos da criopreservação, diluidores utilizados, entre outros. O presente estudo teve como objetivos: 1- determinar a temperatura mais adequada para o armazenamento do testículo após o abate do animal (4 ou 34ºC) levando-se em consideração testes funcionais e fecundação in vitro; 2- avaliar o efeito desta temperatura de armazenamento no sêmen epididimário fresco e criopreservado e; 3- verificar a eficiência do tratamento com ácido decosaexanóico (DHA) e antioxidantes adicionados ao diluidor. Para isso, amostras espermáticas foram coletadas da cauda do epidídimo de touros provenientes de abatedouros. Para testar o efeito da temperatura de acondicionamento dos testículos, os mesmos foram armazenados entre 2 e 4 horas após o abate, à temperatura de 4 ou 34º C. O sêmen foi então coletado da cauda do epidídimo, submetido ou não à criopreservação e avaliado quanto a análise computadorizada da motilidade espermática (CASA), integridade de membrana e potencial mitocondrial (iodeto de propídeo, SYBR e JC1), fertilização in vitro e susceptibilidade ao estresse oxidativo (TBARS). Visto que os resultados deste experimento indicaram que a temperatura de 4ºC era a mais indicada, a mesma foi utilizada para a avaliação do efeito da suplementação com DHA e antioxidantes adicionados ao diluidor. Nesta fase, o sêmen foi avaliado quanto à integridade de membrana e acrossomo (eosina/nigrosina e fast green/rosa bengala, respectivamente), atividade mitocondrial (diaminobenzidina), integridade do DNA (ensaio da estrutura da cromatina espermática SCSA) e susceptibilidade ao estresse oxidativo (TBARS). Os resultados do presente estudo indicam que o tratamento com o DHA tornou os espermatozóides mais susceptíveis aos danos causados pelo estresse oxidativo. Por outro lado, resultados diversos foram encontrados com a associação entre DHA e antioxidantes. A associação entre DHA e superóxido dismutase (SOD) e DHA e glutationa reduzida (GSH) apresentaram os melhores resultados em relação à motilidade espermática e à integridade de membrana, respectivamente. No entanto, o DHA, quando associado à Vitamina E, apresentou resultados negativos para a atividade mitocondrial. Os resultados do presente estudo indicam que o tratamento com DHA e SOD ou DHA e GSH em amostras espermáticas coletadas de epidídimos armazenados a 4ºC por até 4 horas, pode melhorar a qualidade espermática pós criopreservação.Sperm recovery from the cauda epididymis can be very advantageous, for example: in case of the unexpected death of a genetically highly valuable animal, as an experimental model for research on semen and for the use in endangered species. However, the efficiency of this technique demands the study of several issues such as the storage conditions of the testicles prior semen collection, the effects of cryopreservation and semen extenders, among others. The objective of the present study was: 1- to evaluate the ideal temperature for testicles storage after slaughter (4 or 34ºC) based on functional tests and on in vitro fertility; 2- to evaluate the effect of storage temperature on fresh and cryopreserved semen samples, and; 3- to test the addition of decosaexanoic acid (DHA) and antioxidants to the semen extender. Sperm samples were collected from the caudae epididymides of testicles collected from abattoirs. To test the effect of temperature of storage, testicles were kept under 4 or 34ºC, between two to four hours after slaughter. Semen was then collected from the caudae epididymides and cryopreserved or not. Samples were then evaluated for computer assisted sperm analysis (CASA), membrane integrity and mitochondrial potential (propidium iodide, SYBR and JC1), in vitro fertilization outcomes, and susceptibility to the oxidative stress (TBARS). Results of this study indicated that, with no doubt, storage of testicles under 4ºC is the most appropriate in order to improve post-thaw sperm quality and in vitro fertility. Therefore, this temperature was used in the rest of the study to test the effect of DHA and antioxidant treatments to the semen extender. In this part of the study, semen was evaluated for membrane and acrosome integrities (eosin/nigrosin and fast green/bengal rose stain, respectively), mitochondrial activity (diaminobenzidine stain), DNA integrity (sperm chromatin structure assay SCSA) and, sperm susceptibility to the oxidative stress (TBARS). Results of the present study indicate that due to the treatment with DHA, epididymal sperm became more susceptible to the oxidative stress. On the other hand, different results were found regarding the association between DHA and antioxidant. The association between DHA and superoxide dismutase (SOD) and between DHA and reduced glutathione (GSH) showed better results on sperm motility and membrane integrity, respectively. On the other hand, when associated to the Vitamin E, the DHA showed poor results on mitochondrial activity. Results of the present study indicate that the treatment with DHA and SOD or GSH to epididymal sperm samples collected from testicles stored at 4ºC for up to 4 hours, may improve post-thaw sperm quality.
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何子雅 and Tsz-nga Ho. "The role of free radicals and antioxidants in motor neurone degenerative disease." Thesis, The University of Hong Kong (Pokfulam, Hong Kong), 1998. http://hub.hku.hk/bib/B31215294.
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Ho, Tsz-nga. "The role of free radicals and antioxidants in motor neurone degenerative disease /." Hong Kong : University of Hong Kong, 1998. http://sunzi.lib.hku.hk/hkuto/record.jsp?B19737786.
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Thompson, Dylan. "Muscle damage and soreness following prolonged intermittent shuttle running and the effect of vitamin C supplementation." Thesis, Loughborough University, 1999. https://dspace.lboro.ac.uk/2134/10849.
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Exercise-induced muscle soreness and damage have been investigated for almost a century, and yet it appears that there is little that can be done to avoid these consequences of over-exertion, except train on a regular basis. It is likely that freeradicals are involved at a number of stages in the muscle damage process, and therefore the provision of appropriate antioxidants may theoretically offer some protection. One such antioxidant is vitamin C, although the literature available in support of this notion is scarce. The aim of these studies, therefore, was to assess whether different nutritional interventions using vitamin C would offer any benefit to exercise-induced muscle damage and soreness. In the past, investigators have often used exercise protocols designed to maximise the extent of injury. The studies reported in this thesis, however, used an exercise protocol (Loughborough Intermittent Shuttle Test: LIST) based on the multiple-sprint sports (e.g. football). Participation in such sports is very high, although frequently on an irregular basis, and therefore exercise of this nature may have the capacity to cause muscle damage and soreness. The LIST provided a suitable exercise model, and in different studies led to increases in soreness, markers of muscle damage, lipid peroxidation, and inflammation. It also led to poorer muscle function up to 72 h after exercise in some muscle groups. Short-term supplementation with vitamin C 2 hours before exercise successfully increased plasma and cellular concentrations, although failed to have any beneficial outcomes in terms of muscle damage or soreness. Supplementation in the hours and days (up to three days) after exercise also produced no beneficial effects, and it may be that supplementation occurred at an inappropriate time. Prolonged supplementation with vitamin C proved more promising (14 days), and was associated with reduced plasma concentrations of interleukin-6 and malondialdehyde. Furthermore, there were modest benefits to certain' aspects of muscle soreness and function, although these were not always statistically significant. However, tliere was no effect on circulating markers of muscle damage (creatine kinase and myoglobin). These findings suggest that the regular ingestion of vitamin C may be associated with some favourable changes following damaging exercise. However, the consumption of large amounts of vitamin C immediately before or after exercise offer no appreciable benefits, despite large changes in plasma concentrations of this vitamin.
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McDonagh, Margaret P. "The role of energy restriction and environmental agent exposure in the aetiology of malnutrition related diabetes mellitus (MRDM)." Thesis, University of Ulster, 1997. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.390162.
Full textBooks on the topic "Free radicals; Antioxidants"
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Poljsak, Borut. Skin aging, free radicals, and antioxidants. New York: Nova Science Publishers, 2012.
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Özben, Tomris, ed. Free Radicals, Oxidative Stress, and Antioxidants. Boston, MA: Springer US, 1998. http://dx.doi.org/10.1007/978-1-4757-2907-8.
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Knight, Joseph A. Free radicals, antioxidants, aging and disease. Washington, D.C: AACC Press, 1999.
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Barry, Halliwell, ed. Antioxidants in nutrition, health, and disease. Oxford: Oxford University Press, 1994.
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E, Cooper Chris, Wilson M. T, and Darley-Usmar V. M, eds. Free radicals: Enzymology, signalling and disease. London: Portland, 2004.
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Cooper, Kenneth H. Dr. Kenneth H. Cooper's antioxidant revolution. Nashville: T. Nelson Publishers, 1994.
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Smythies, John R. Every person's guide to antioxidants. New Brunswick, N.J: Rutgers University Press, 1998.
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Lin, David J. Free radicals and disease prevention: What you mustknow. New Canaan, Conn: Keats Pub, 1993.
Find full textBook chapters on the topic "Free radicals; Antioxidants"
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Okuda, Takuo. "Phenolic Antioxidants." In Food and Free Radicals, 31–48. Boston, MA: Springer US, 1997. http://dx.doi.org/10.1007/978-1-4899-1837-6_4.
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Hiramatsu, Midori. "Mixed Natural Antioxidants." In Food and Free Radicals, 113–17. Boston, MA: Springer US, 1997. http://dx.doi.org/10.1007/978-1-4899-1837-6_10.
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Terao, Junji, Syunji Oshima, Fumihiro Ojima, Peng Lim Boey, and Akihiko Nagao. "Carotenoids as Antioxidants." In Food and Free Radicals, 21–29. Boston, MA: Springer US, 1997. http://dx.doi.org/10.1007/978-1-4899-1837-6_3.
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Agarwal, Ashok, and Ahmad Majzoub. "Free Radicals in Andrology." In Antioxidants in Andrology, 1–21. Cham: Springer International Publishing, 2016. http://dx.doi.org/10.1007/978-3-319-41749-3_1.
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Webb, Geoffrey P. "Free Radicals and Antioxidants." In Dietary Supplements and Functional Foods, 145–60. West Sussex, UK: John Wiley & Sons Ltd., 2013. http://dx.doi.org/10.1002/9781118788660.ch5.
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Fried, Robert, and Lynn Nezin. "Antioxidants Neutralize Free Radicals." In Evidence-Based Proactive Nutrition to Slow Cellular Aging, 35–70. Boca Raton, Florida : CRC Press, 2017.: CRC Press, 2017. http://dx.doi.org/10.1201/9781315173221-3.
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Sundaram Sanjay, Sharda, and Ashutosh Kumar Shukla. "Free Radicals Versus Antioxidants." In Potential Therapeutic Applications of Nano-antioxidants, 1–17. Singapore: Springer Singapore, 2021. http://dx.doi.org/10.1007/978-981-16-1143-8_1.
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McMullen, Roger L. "Free radicals in biology." In Antioxidants and the Skin, 21–29. Second edition. | Boca Raton, FL : CRC Press/Taylor & Francis Group, [2019]: CRC Press, 2018. http://dx.doi.org/10.1201/9781315207254-2.
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Bors, Wolf, Christa Michel, Werner Heller, and Heinrich Sandermann. "Flavonoid Radicals." In Free Radicals, Oxidative Stress, and Antioxidants, 85–92. Boston, MA: Springer US, 1998. http://dx.doi.org/10.1007/978-1-4757-2907-8_8.
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Kumari, M. V. Ramana. "Potential Antioxidants from Minor Dietary Constituents." In Food and Free Radicals, 123–28. Boston, MA: Springer US, 1997. http://dx.doi.org/10.1007/978-1-4899-1837-6_12.
Full textConference papers on the topic "Free radicals; Antioxidants"
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Fomenko, M. P., A. M. Menzheritsky, and G. V. Karantysh. "INFLUENCE OF PINEALON ON EXPRESSION OF GENES OF PRO- AND ANTIOXIDANT ENZYMES AND FREE RADICAL PROCESSES IN RATS IN THE MODEL OF SUGAR DIABETES." In STATE AND DEVELOPMENT PROSPECTS OF AGRIBUSINESS Volume 2. DSTU-Print, 2020. http://dx.doi.org/10.23947/interagro.2020.2.232-234.
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The article presents an analysis of the effect of pinealon on free radical processes and the level of expression of the SOD1, GPX4 and GSR genes in the rat hippocampus in a model of streptozotocininduced diabetes (type I diabetes mellitus). It has been established that when modeling diabetes in the hippocampus, intensification of radically radical processes is observed: the level of prooxidants increases, the level of antioxidants decreases, as well as the level of expression of antioxidant genes. With the introduction of pinealone in dosages of 50 or 100 ng/kg in the model of diabetes mellitus, the pro-antioxidant balance shifts towards a decrease in the production of free radicals and an increase in antioxidant protection. Pinealon at a dosage of 100 ng/kg is more effective.
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Caverina, Sarah Lorenza, Retno Yulianti, and Andri Pramesyanti. "Effectiveness of Soursop Leaf Extract to Decrease Malondialdehyde Level." In The 7th International Conference on Public Health 2020. Masters Program in Public Health, Universitas Sebelas Maret, 2020. http://dx.doi.org/10.26911/the7thicph.05.07.
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ABSTRACT Background: In diabetes mellitus, hyperglycemia causes oxidative stress that enhances the production of free radicals. The presence of higher levels of malondialdehyde (MDA) indicates the rise of free radicals. On the basis of its role as an antioxidant that binds free radicals and reduces the level of malondialdehyde (MDA). Soursop leaf can act as an antidiabetic agent. This study aimed to examine the efficacy of soursop leaf extract (Annona muricata L.) to decrease the level of MDA level in alloxan-induced diabetic rats (Rattus norvegicus). Subjects and Method: This was an experiment study using pre- and pro-test with control group design. Total of 30 rats were selected for this study and divided into five groups of treatment i.e. group I was given distilled water and standard feed (Negative Control/KI), group II was given vitamin E 150 IU/kgBW/day (Positive Control/KII), group III was given soursop leaf extract 75 mg/kgBW/day (KIII), group IV was given soursop leaf extract 150 mg/kgBW/day (KIV), and group V was given soursop leaf extract 300 mg/kgBW/day (KV). Each group consisted of 5 rats and was given soursop leaf extract for 21 days after being induced by alloxan and high-fat diet. The data were analyzed using Mann-Whitney test. Results: There was a significant difference in KI group compared to KII, KIII, KIV, and KV groups. Soursop leaf extract of 150 mg/kgBW/day was the most effective dose to reduce MDA level in pancreatic rat. Conclusion: Soursop leaf extract of 150 mg/kgBW/day is the most effective dose on pancreatic MDA level reduction. Keywords: diabetes mellitus, soursop leaf extract, MDA, free radical Correspondence: Retno Yulianti. Department of Anatomical Pathology, Faculty of Medicine Universitas Pembangunan Nasional “Veteran” Jakarta. Jl. Fatmawati Hospital, Pondok Labu, South Jakarta. Email: retno.yulianti@upnvj.ac.id DOI: https://doi.org/10.26911/the7thicph.05.07
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Shatos, M., J. Doherty, D. Allen, and J. Hoak. "ALTERATIONS IN VASCULAR ENDOTHELIAL CELL FUNCTION BY OXYGEN-FREE RADICALS." In XIth International Congress on Thrombosis and Haemostasis. Schattauer GmbH, 1987. http://dx.doi.org/10.1055/s-0038-1643365.
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The vascular endothelium is a target for oxidant-induced damage in many disease states including hyperoxia, inflammation, ischemia and reperfusion injury. However, little is known concerning oxidant injury to endothelial cells and its relationship to hemostasis. Our studies have focused on the ability of oxygen free radicals to injure and/or alter selected vascular endothelial cell functions pertinent to the regulation of hemostasis. Xanthine and xanthine oxidase, a well-characterized generating system for the production of the superoxide anion radical (O− 2) was used to sublethally injure human umbilical vein endothelial cells (HUVE) in vitro. We examined the effects of a 15 min exposure of HUVE cells to xanthine (50μM), and xanthine oxidase (2.5-100mU) (previously determined to be non-toxic using trypan blue dye exclusion) on platelet adherence, and prostacyclin release using established assays. The antioxidant enzymes superoxide dismutase (SOD) 200μg/ml and catalase 50μg/ml were added to endothelium incubation systems to evaluate any protective effects upon O− 2-induced alterations. All experiments were conducted in a serum-free HEPES-Tyrode's buffer, pH 7.4 incubation system. Our results show that exposure of HUVE cells to sublethal concentrations of oxygen free radical generating systems causes significant enhancement of platelet adherence (65%) to injured endothelium. A 12-fold increase in prostacyclin release resulted after a 15 min treatment with xanthine and xanthine oxidase. The addition of exogenous PGI2 (150nM) to platelet-endothelial systems did not completely prevent the enhanced platelet adherence suggesting that lack of prostacyclin was not completely responsible for the adherence of platelets to O− 2 injured cells. When SOD and catalase, scavengers of O− 2 and H2O− 2, were added to treated cells, platelet adherence decreased by 42-77% and prostacyclin release approached that of control cultures. These data implicate an active participation of activated metabolites of molecular oxygen in the alteration of vascular endothelial cell function.
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Gao, Jia-min, Fan Shi, Jia-zhen Du, Zhi-Ping Wang, Tong-Sheng Chen, and Yi-fei Wang. "Evaluation of free-radical scavenging and antioxidant activities of polydatin nanoethosomes." In Nanophotonics and Micro/Nano Optics IV, edited by Zhiping Zhou and Kazumi Wada. SPIE, 2018. http://dx.doi.org/10.1117/12.2500148.
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Mladenova, Ralitsa, Katerina Aleksieva, Nikolay Solakov, and Kamelia Loginovska. "Study of gamma radiation effects on free radicals generation and antioxidant potential of beebread." In RAD Conference. RAD Centre, 2021. http://dx.doi.org/10.21175/rad.abstr.book.2021.13.6.
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Jones, E. Grant, Walter J. Balster, and Lori M. Balster. "Evaluation of the Effectiveness of a Metal Deactivator and Other Additives in Reducing Insolubles in Aviation Fuels." In ASME 1996 International Gas Turbine and Aeroengine Congress and Exhibition. American Society of Mechanical Engineers, 1996. http://dx.doi.org/10.1115/96-gt-204.
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Surface fouling in aircraft fuel lines resulting from autoxidation of aviation fuel leads to reduced efficiency as deposits collect on heat exchangers, nozzles, and servocontrols and may ultimately lead to system failure. Metal surfaces and trace quantities of metals dissolved in the fuel exacerbate the surface-fouling problem because they can catalyze free-radical initiation, thereby accelerating autoxidation. Additives and additive packages containing antioxidants, dispersants, and metal deactivators (MDA) have been shown to reduce insolubles in some fuels. Because of metal chelation and possible metal-surface passivation, MDA has been proposed as an additive component to be included in all fuels, even those without dissolved metals. The goal of the present study was to obtain fundamental information on the behavior of MDA under conditions where surface-passivation effects are minimal. Experiments have been conducted to 1) study the effects of adding MDA to fuels containing a significant concentration of dissolved metals (i.e., chelation) and to those containing minor concentrations of dissolved metals and 2) investigate interactions when MDA is used in conjunction with an antioxidant and a dispersant. Simple fuel-line-fouling simulations with a single-pass tubular heat exchanger operated under near-isothermal conditions have been conducted to study the thermal behavior at 185°C of several neat and MDA-treated jet fuels as well as fuels treated with MDA plus other additives. Comparison of neat and treated fuels is based on several criteria: 1) dependence of autoxidation on stress duration, 2) dependence of surface deposition on stress duration, and 3) quantity of total insolubles (bulk filterables and surface deposits). Potential advantages and disadvantages of using MDA alone and in combination are discussed.
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Rai, Durg V., and Harcharan Singh Ranu. "Ovariectomy and its Antioxidative Effect on Bone." In ASME 2010 International Mechanical Engineering Congress and Exposition. ASMEDC, 2010. http://dx.doi.org/10.1115/imece2010-40581.
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Ovarian hormone deficiency increases the generation of reactive oxygen species. Oxidative stress due to reactive oxygen species (ROS) can cause oxidative damage to cells. Cells have a number of defense mechanisms to protect themselves from the toxicity of ROS. There is increasing evidence of the role of free radicals in bone resorption and bone loss. Ovariectomised female wistar rats had been used as the animal model for the study of osteoporosis. Even though, there are studies portraying the role of free radicals in bone loss, the defense mechanism adapted by bone in ovariectomised animals remains obscure. So, the impact of ovariectomy on the bone antioxidant system in rats was investigated. Twenty female wistar rats were taken and divided into two groups: ovariectomised and control. It had been found that a significant (p<0.001) decrease in the activity of various enzymes like CAT (catalase), SOD (superoxide dismutase) (p<0.001), GST (glutathione-s-transferase). However, an increase in the malondialdehyde levels was found to be 30% in the ovariectomised rats as compared to the controls. Thus the study elucidates the oxidative stress in bone under ovariectomy.
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Oliveira, R. A., C. T. Soares, F. G. Nogueira, and A. A. Santana. "Vitamin C content of freeze dried pequi (Caryocar brasiliense Camb.) pulp." In 21st International Drying Symposium. Valencia: Universitat Politècnica València, 2018. http://dx.doi.org/10.4995/ids2018.2018.7803.
Full textAbstract:
Vitamin C is one of the constituents of pequi pulp. It is a natural antioxidant, capable of sequestering free radicals. The present study aimed to freeze dry a pequi pulp encapsulated with maltodextrin and whey protein and analyze vitamin C content. Vitamin C loss was lower in the experimental run that did not use encapsulating agent. Whereas, the run that used 15% of whey protein concentrate as encapsulant agent in relation to pequi solids presented the highest value (220.74 mg vitamin C / g pequi solids). Freeze drying of pequi pulp is a technique for vitamin C conservation independently of the variation in maltodextrin and whey protein proportion.Keywords: drying; encapsulating agent; ascorbic acid.
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Varela, D., R. O’Hara, and A. C. Neves. "BY-PRODUCTS OF THE WHELK PROCESSING INDUSTRY AS VALUABLE SOURCE OF ANTIOXIDANT PEPTIDES." In World Conference on Waste Management. The International Institute of Knowledge Management, 2021. http://dx.doi.org/10.17501/26510251.2021.1103.
Full textAbstract:
The fish and shellfish industry processes 851,984 tonnes of fish per year worldwide. However, only 43% of that is consumed, and valuable proteins are processed as waste. Protein hydrolysates are widely used in food technology for their nutritional and functional properties. The goal of this project is to extract protein from whelk by-products derived from the shellfish processing industry and create protein hydrolysates that have marketable value. The by-products were divided into two types: raw (R) and cooked byproduct (C). The proteins were extracted using the pH shift method and quantified using the Bradford assay. It was possible to extract a maximum of 455 mg/g at a neutral pH, for which R had the highest protein yield. Proteins were also qualified using reverse phase high-performance liquid chromatography (RP-HPLC) that showed that R has more hydrophilic proteins while the C extracted protein showed more peaks in the hydrophobic phase. The Fourier-transform infrared spectroscopy (FTIR) indicated the presence of glutamine, tyrosine, and serine in the extracted proteins. Extracted proteins were then hydrolyzed using Alcalase and α-Chymotrypsin. It was possible to obtain higher degrees of hydrolysis (DH) using Alcalase. The hydrolysates were tested for antioxidant activity using the DPPH (2,2-diphenyl-1-picryl-hydrazyl-hydrate) free radical antioxidant assay. Alcalase hydrolysates showed to have overall lower IC50 for stabilization of the DPPH radical than α-Chymotrypsin, the lowest one being 13.92±1.57 µg/mL for the Alcalase hydrolyzed neutral proteins. The IC50 results obtained are significantly lower than the ones described in other studies using the same enzymes or other marine species. This can indicate that more heterogenous mixtures of by-product can originate extracted proteins that when hydrolyzed lead to higher radical scavenging activity, thus making shellfish industry by-product a sustainable and valuable source of antioxidant peptides. Keywords: Shellfish; Bioactive peptides; Protein extraction; Protein hydrolysates, Waste management, Nutraceuticals
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Berechet, Mariana Daniela, Demetra Simion, Maria Stanca, Cosmin Andrei Alexe, Rodica Roxana Constantinescu, Maria Rapa, and Andreea Turcanu. "Antibacterial and antioxidant activities of lemon balm (Melissa officinalis L.) essential oil." In The 8th International Conference on Advanced Materials and Systems. INCDTP - Leather and Footwear Research Institute (ICPI), Bucharest, Romania, 2020. http://dx.doi.org/10.24264/icams-2020.ii.2.
Full textAbstract:
Lemon balm (Melissa officinalis L.) belongs to the Lamiaceae family. Essential oil extracted from the aerial parts of lemon balm has been investigated for the protection of fruits during storage, as insecticidal, as well as in medicine, due to its bioactive properties. In this paper, the composition and identification of components from Melissa officinalis L. essential oil were determined by gas chromatography coupled with mass spectrophotometry (GC/MS) analysis. Total phenol content (TPC) and the scavenging activity towards 2,2-diphenyl-1-picrylhydrazyl (DPPH·) and 2,2′-azino-bis (3-ethylbenzthiazoline)-6-sulfonic acid (ABTS+·) free radicals were evaluated by UV-VIS spectrometry. Antibacterial activities were carried out against Staphylococcus aureus, Escherichia coli and Klebsiella pneumoniae. Seventeen bioactive compounds were found as constituents of Melissa officinalis L. essential oil, among which o-cymene (19.735%), dehydro-p-cymene (17.180%), and limonene (11.589%) were found as the major components. Attenuated total reflectance Fourier transform infrared spectroscopy (ATR-FT-IR) provided a confirmation for the chemical components of lemon balm essential oil identified by GC/MS. The values recorded for TPC and antioxidant activity were as follows: 54.72 mg GAE/g dry substance, 28.53% for DPPH, and 46.17% for ABTS assays, respectively. 100 µL lemon balm essential oil proved total antibacterial activity against the tested microorganisms. The results showed that the Melissa officinalis L. may be a good candidate as plant-derived antioxidant and antibacterial agent for medical footwear, wound dressings and other medical applications.