Tea is one of the oldest and most consumed beverages in the world, being mentioned as one of the best sources of phenolic compounds. These substances have been studied especially because they have antioxidant activity. The term refers to tea product herbal infusions the genus Camellia sp. Being that variations in their designations are relative to the type of process that these plants suffer. Antioxidants are substances used to preserve food through the retardation of deterioration, rancidity and discoloration resulting from autoxidation, while biological systems that protect against the damaging effects of reactions of reactive oxygen species. Various methods are used to determine the antioxidant activity of extracts and compounds isolated. One of the most widely used is to evaluate the scavenging activity of the stable free radical DPPH (1,1-diphenyl-2-picryl-hydrazyl). Other methodologies used to evaluate the antioxidant capacity of an extract are the determination of total phenolic compounds, total polyphenol content, and iron reduction technique. In this context, the objective of this study was to determine the content of bioactive compounds, characterized by its value of antioxidant activity, flavonoids and phenolic compounds in different types of tea come from the Camellia sinensis plant, namely: green tea, black tea, white tea, yellow tea and red tea. The experiment was conducted in the post harvest fruit core research, located in the Department of Plant Science, Federal University of Santa Maria, RS. The samples were extracted by infusion sachets of filter paper containing 3 g of the plant in 200 ml of distilled and deionized water by 10 minutes of infusion, at 85 °C. After extraction the samples were placed in glass containers protected from light and stored at a temperature of 0.5 °C. Determination of antioxidant activity by DPPH method was performed by evaluation of polyphenols and flavonoids (colorimetric method), and the chelating activity of Fe+2. As a result, white tea showed the highest antioxidant activity among teas evaluated considering the kidnapping of DPPH. This tea also showed the highest levels of flavonoids and phenolic compounds. Green tea showed higher antioxidant activity as measured by the percentage of ferrous ion chelating activity. Among the 20 types of teas evaluated, hibiscus tea has lowest antioxidant properties. Among the teas originating from Camellia sinensis, the red tea showed the lowest values of antioxidant activity, regardless of the method or evaluation performed, but did not differ from black tea, white and yellow in the percentage of ferrous ion chelating activity. Considering the results of EC50, ilex tea, bilberry and gorse showed intermediate antioxidant power in relation to the Camellia sinensis teas and other teas evaluated in this work. / O chá é uma das bebidas mais antigas e consumidas do mundo, sendo referido como uma das melhores fontes de compostos fenólicos. Estas substâncias têm sido alvo de estudo especialmente por apresentarem atividade antioxidante. O conceito de chá refere-se ao produto de infusões de plantas do gênero Camellia sp., sendo que as variações em suas denominações são relativas ao tipo de processo que estas plantas sofrem. Antioxidantes são substâncias usadas para conservar alimentos através do retardo da deterioração, rancidez e descoloração, decorrentes da auto-oxidação, ao mesmo tempo em que protegem os sistemas biológicos contra os efeitos danosos de reações das espécies reativas ao oxigênio. Vários métodos são utilizados para determinar a atividade antioxidante em extratos e substâncias isoladas. Um dos mais utilizados consiste em avaliar a atividade seqüestradora do radical livre estável DPPH (1,1-difenil-2-picril-hidrazil). Outras metodologias utilizadas para avaliar a capacidade antioxidante de um extrato são a determinação dos compostos fenólicos totais, o conteúdo de polifenóis totais, e a técnica de redução do ferro. O objetivo do presente trabalho foi determinar o teor de compostos bioativos, caracterizados pelo seu respectivo valor de atividade antioxidante, compostos fenólicos e flavonóides, em chás oriundos de 20 diferentes plantas, incluindo a Camellia sinensis (chá verde, chá preto, chá branco, chá amarelo e chá vermelho). O experimento foi realizado no Núcleo de Pesquisa em Pós-Colheita, localizado no departamento de Fitotecnia da Universidade Federal de Santa Maria, RS. As amostras foram extraídas através da infusão de saches de papel filtro contendo 3 g da planta em 200 mL de água destilada e deionizada por 10 minutos de infusão, a 85°C. Após a extração as amostras foram acondicionadas em recipientes de vidro protegidos da ação da luz e armazenadas a temperatura de 0,5°C. A determinação da atividade antioxidante foi realizada pelo método DPPH, e pela atividade quelante de íons Fe+2. Como resultado, o chá branco apresentou a maior atividade antioxidante entre os chás avaliados, considerando o seqüestro de radical DPPH. Este chá apresentou também os maiores teores de flavonóides e polifenóis totais. O chá verde apresentou maior atividade antioxidante quando avaliada pela porcentagem de atividade quelante de íons ferroso. Entre os 20 tipos de chás avaliados, o chá de hibiscus praticamente não apresenta propriedades antioxidantes. Entre os chás oriundos da Camellia sinensis, o chá vermelho foi o que apresentou os menores valores de atividade antioxidante, independente do método ou avaliação realizada, porém não diferindo do chá preto, branco e amarelo na porcentagem de atividade quelante de íons ferroso. Considerando os resultados de EC50, chás de erva mate, carqueja e boldo apresentaram poder antioxidante intermediário em relação aos chás da planta Camellia sinensis e aos demais chás avaliados no presente trabalho.

The present study was undertaken to determine the effects and possible mechanism of action of cimetidine in cancer and Alzheimer’s disease (AD). Throughout this study emphasis is placed on free radical levels since the magnitude of the relationship between diseases and the levels of free radicals vary from one disease to another. Studies were carried out to examine the effect of cimetidine on free radical levels using superoxide formation and lipid peroxidation as indicators of free radical levels. The experiments revealed that addition of cimetidine, especially in high concentrations (0.5 and 1.0 x10-6 M) significantly inhibited WHCO6 cancer cell growth rather than cancer cell growth, as no normal control was available. Free radical formation as well as hydroxyl radical formation were reduced in the deoxyribose assay. In addition, cimetidine exhibits properties of binding to metals such as copper and iron. To maintain consistency in the experiments, a WHCO6 (Wits Human Carcinoma of the Oesophagus) cell line was used to investigate the effect of cimetidine in cancer. Neurodegeneration was induced in the rat brain using neurotoxins such as cyanide to investigate the relationship between cimetidine in AD. A decrease in cancer cell growth was accompanied by a concomitant decrease in the levels of free radicals and lipid peroxidation, suggesting that the growth-inhibitory effects of cimetidine on WHCO6 cancer cells in vitro may be due to free radical scavenging properties. This proposal was further strengthened by determination of free radical levels in the rat brain. After treatment with neurotoxins to induce neurodegeneration, the levels of free radicals in the rat brain suggest that addition of cimetidine reduces free radical levels in the rat brain in a dosedependent manner. Further experiments were done in an attempt to uncover the underlying mechanism by which cimetidine exhibits free radical scavenging properties. Metal binding studies were done using electrochemical, HPLC and UV/Vis studies. The results show that cimetidine binds iron and copper. These metals have been implicated in free radical production via the Fenton reaction. By binding with cimetidine the metals become unavailable to produce free radicals and hence cimetidine indirectly reduces the formation of free radicals. The final experiment was the determination of cimetidine as a hydroxyl radical scavenger in the deoxyribose assay. Cimetidine was shown to act as a potent hydroxyl radical scavenger, thereby confirming its activity as a free radical scavenger. In addition, cimetidine protects against damage to the deoxyribose sugar, a component of DNA. Whilst there are many theories that explain the therapeutic role of cimetidine in degenerative disease, the actual mechanism of the role of cimetidine is emphasized as a free radical scavenger. Regardless of the mechanism of action, cimetidine does inhibit tumour growth according to this study and also reduce free radical levels in neurodegeneration, which suggests a role for cimetidine as a possible additive in treatment of patients with such disease states. These findings have important clinical implications, and needs to be investigated further.

Depuis sa découverte, la spectroscopie de Résonance Magnétique Nucléaire (RMN) a permis de grandes avancées scientifiques dans de nombreux domaines allant de la physique à la médecine. L'inconvénient majeur de la RMN est sa faible sensibilité intrinsèque, due à la très faible polarisation des spins nucléaires. Au cours de ces 20 dernières années, la Polarisation Dynamique Nucléaire (PDN) s'est développée comme technique très prometteuse permettant d'augmenter la polarisation de spin nucléaire, et l'intensité des signaux en RMN liquide ou solide de plusieurs ordres de grandeur. Dans les mêmes conditions expérimentales, la polarisation de spin de l'électron est beaucoup plus grande que la polarisation de spin nucléaire et la PDN permet le transfert de cette forte polarisation à partir d'un agent de polarisation paramagnétique (habituellement un radical libre organique) vers les noyaux avoisinants. L'augmentation de l'intensité du signal RMN (I) est caractérisé par un facteur d'exaltation ε=I(μw ON)/I(μw OFF).L'objectif principal de cette thèse est la synthèse d'agents de polarisation, de type dinitroxyde, solubles dans l'eau et très efficaces pour des expériences de MAS ssNMR/PDN. Nous avons préparé une large série de dérivés du bTurea solubles dans l'eau et leurs performances PDN ont été évaluées à différent champs magnétiques. En remplaçant les groupements méthyl des fonctions TEMPO par des cycles pyranyl, ainsi qu'en introduisant des chaînes PEG sur le linker urée, AMUPol (ε=247) et PyPolPEG2OH (ε=303) ont entre autres été obtenus. Ce sont actuellement les agents de polarisation les plus efficaces pour des expériences de MAS ssNMR/PDN en milieux aqueux. / Nowadays, Nuclear Magnetic Resonance (NMR) spectroscopy has become a very powerful technique that can be used to address a wide range of problems, ranging from physics to medicine. The major limitation of NMR is its intrinsic low sensitivity, resulting from the very small nuclear spin polarizations observed even at high magnetic fields. During the last two decades, Dynamic Nuclear Polarization (DNP) has emerged as a very promising approach to enhance NMR signal intensities of solids and liquids by several orders of magnitude. All things being equal, electron spin polarization is much higher than nuclear spin polarization and DNP exploits the microwave-driven transfer of polarization from a paramagnetic polarizing agent (usually an added exogenous organic free radical) to the surrounding nuclei. The enhancement of NMR signal intensities (I) is characterized by the enhancement factor ε=I(μw ON)/I(μw OFF). The main objective of this PhD thesis was the development of new water-soluble dinitroxides, highly efficient polarizing agents for MAS solid-state NMR/DNP applications. We have designed and prepared a large series of water-soluble bTurea (TEMPO-N(H)-C(O)-(H)N-TEMPO), derivatives, and their DNP performance was tested at different magnetic fields (mainly 9.4 T). Replacing the methyl groups of TEMPO moieties with pyranyl rings, and introducing PEG chains on the urea linker we obtained, among others, two derivatives, AMUPol (ε = 247) and PyPolPEG2OH (ε = 303) which are currently the most efficient water-soluble polarizing agents for MAS ssNMR/DNP experiments for aqueous media.

Orientador: Américo Bortolazzo Correr / Dissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Odontologia de Piracicaba / Made available in DSpace on 2018-08-22T02:50:31Z (GMT). No. of bitstreams: 1 Gotti_ValeriaBisinoto_M.pdf: 22569671 bytes, checksum: 63a18f68fe04710cbb552ebb07904779 (MD5) Previous issue date: 2013 / Resumo: O resumo poderá ser visualizado no texto completo da tese digital / Abstract: The abstract is available with the full electronic document / Mestrado / Materiais Dentarios / Mestra em Materiais Dentários

Os mecanismos oxidativos pelos quais macrófagos exercem atividade microbicida permanecem em discussão, e estudos com hospedeiros animais serão essenciais para elucidar tal questão. Nesse trabalho, estudamos os mecanismos microbicidas de macrófagos in vivo comparando parâmetros de infecção nas lesões de camundongos resistentes (C57Bl/6) e suscetíveis (BALB/c) ao protozoário Leishmania amazonensis. A comparação mostrou que o controle da infecção pelos camundongos resistentes é dependente da ativação de macrófagos com expressão da enzima óxido nítrico sintase induzível, síntese de óxido nítrico e extensa nitração e hidroxilação das proteínas dos parasitas dentro dos fagolisossomos dos macrófagos. O principal agente tóxico aos parasitas parece ser derivado do peroxinitrito porque a nitração dos parasitas ocorreu na ausência virtual de células polimorfonucleares e foi acompanhada de hidroxilação. Além disso, tempol um inibidor de reações de nitração mediadas por peroxinitrito, inibiu a nitração de proteínas da lesão e aumentou o número de parasitas nelas presentes. Também, estudos com parasitas em cultura confirmaram que o peroxinitrito é citotóxico aos parasitas enquanto o óxido nítrico é citostático. O camundongo suscetível se mostrou capaz de sintetizar óxido nítrico mas o fez em estágios tardios da infecção e, provavelmente, em resposta a uma infecção secundária por bactérias. Tomados conjuntamente, os resultados indicam que o peroxinitrito e radicais dele derivados são os principais agentes leishmanicidas produzidos por macrófagos in vivo. / Macrophage oxidative microbicidal mechanisms remain debatable and their elucidation is likely to depend on studies with mammalian hosts. To examine macrophage microbicidal mechanisms in vivo, we compared infection parameters in the lesions of resistant (C57Bl/6) and susceptible (BALB/c) mice to the protozoan Leishmania amazonensis. This comparison demonstrated that infection control by resistant mice relied on macrophage activation with inducible nitric oxide synthase expression, nitric oxide synthesis and extensive nitration and hydroxylation of the proteins of the parasites inside macrophage phagolysosomes. The toxic agent to the parasite is likely to be peroxynitrite-derived because parasite nitration occurred in the virtual absence of polymorphonuclear cells and was accompanied by parasite hydroxylation. In addition, tempol, an inhibitor of peroxynitrite-mediated nitrations, inhibited protein nitration of the lesions and increased the number of parasites in them. Also, studies with parasite cultures confmed that peroxynitrite is cytotoxic to the parasites whereas nitric oxide is cytostatic. The susceptible mice were also able to synthesize nitric oxide but only at late infection time and, most likely, in response to a secondary bacterial infection. Taken together, the results indicate that peroxynitrite and derived radicals are the main leishrnanicidal agents produced by macrophages in vivo.

O presente estudo avaliou as alterações dos marcadores de estresse oxidativo em cães adultos alimentados com dietas com altos níveis de ácidos graxos (AG) saturados ou insaturado, suplementadas ou não com antioxidante natural à base de algas. Doze cães Beagle adultos sadios (6 machos e 6 fêmeas, 2 anos de idade, 11,2 ± 1,92 kg PV) foram distribuídos em dois blocos inteiramente casualizados e alimentados com 4 dietas experimentais revestidas com 2 fontes lipídicas: saturadas (13% de sebo bovino) ou insaturadas (13% de óleo de soja enriquecido com DHA), suplementadas ou não com 500 mg de antioxidantes naturais à base de algas (AOX) por 4 semanas, intercalados com um período de adaptação de 4 semanas. Amostras de sangue foram coletadas nos dias 0, 15 e 30 de cada bloco. Glutationa peroxidase (GSH-Px), superóxido dismutase (SOD), grupo sulfidrila, carbonilação de proteínas (PC), substâncias reativas ao ácido tiobarbitúrico (TBARS) e potencial antioxidante reativo total (TRAP) foram avaliados no soro. Enquanto GSH-Px, SOD, glutationa S-transferase (GST), catalase (CAT), grupo sulfidrila e TBARS foram medidos nos eritrócitos. Não houve diferença significativa na maioria dos marcadores oxidativos avaliados. Em contraste, a atividade de GST nos eritrócitos foi maior nos animais que consumiram as dietas revestidas com sebo bovino em comparação com animais que consumiram dietas revestidas com óleo de soja enriquecida com DHA (P < 0,05). O soro dos animais alimentados com as dietas suplementadas com AOX apresentaram maiores valores de TRAP (P < 0,05). Os dados demonstraram que as concentrações de ácidos graxos insaturados utilizados nas dietas para cães adultos não foram suficientes para causar grandes alterações no estado oxidativo. Não foi possível avaliar a eficiência do antioxidante natural em manter o equilíbrio oxidativo dos animais, pois parece que o organismo não foi desafiado pelas dietas ricas em AG insaturados. Isso sugere que cães como descendentes de carnívoros podem ter alguma proteção natural contra a oxidação. / The present study evaluated the alterations of the oxidative stress markers in adult dogs fed with high levels of saturated or unsaturated fatty acids, supplemented or not with natural algae based antioxidant. Twelve healthy adult Beagle dogs (6 males and 6 females, 2 years old, 11.2 ± 1.92 kg BW), were distributed in 2 completely randomized blocks and fed with 4 experimental diets coated with 2 lipid sources: saturated (13% bovine tallow) or unsaturated (13% soybean oil enriched with DHA), supplemented or not with with 500 mg of algaebased natural antioxidant (AOX) for 4 weeks, intercalated with a 4 week adaptation period. Blood samples were collected on days 0, 15 and 30 of each block. Glutathione peroxidase (GSH-Px), superoxide dismutase (SOD), sulfhydryl group, protein carbonylation (PC), thiobarbituric acid reactive substances (TBARS) and total reactive antioxidant potential (TRAP) were evaluated in serum. While GSH-Px, SOD, glutathione S-transferase (GST), catalase (CAT), sulfhydryl group and TBARS were measured in erythrocytes. There was no significant difference in most of the oxidative markers evaluated. In contrast, GST activity in erythrocytes was greater in the animals that consumed the diets coated with bovine tallow compared to animals that consumed diets coated with soybean oil enriched with DHA (P < 0.05). Serum from animals fed diets supplemented with AOX presented greater TRAP values (P < 0.05). The data demonstrate that the concentrations of unsaturated fatty acids used in the diets for adult dogs were not sufficient to cause large changes in the oxidative status. It was not possible to evaluate the efficiency of the natural antioxidant in maintaining the oxidative balance of the animals once seems like the body was not challenged by the unsaturated diets. It suggests that dogs descended from carrion carnivore dogs may have some natural protection against oxidation.

This diploma´s thesis deals with the determination of total antioxidant activity of red and white gooseberries and red, white and black currants. There are available information about small fruits, an overview of natural and synthetic antioxidants and a summary of the methods to determine the total antioxidant activity in the theoretical part. Frozen fruit samples were provided by Research and Breeding Institute of Pomology Holovousy Ltd. in the project QI111A141 – Research of new technologies in the cultivation of gooseberries and currants with a focus on quality and use of fetuses (Ministry of Agriculture). The total antioxidant activity of red and white gooseberries and currants was measured by spectrophotometric methods using free radicals ABTS•+ and DPPH and was expressed as a Trolox equivalent. The total antioxidant activity of black currants was measured by electron paramagnetic resonance using free radicals ABTS•+ and DPPH and expressed as a TEACABTS and a TEACDPPH. There were measured 8 species of red gooseberries, 6 species of white gooseberries, 12 species of red currants, 6 species of white currants and 8 species of black currants in this thesis. The highest values of total antioxidant activity showed species of red and white gooseberries Alan, Karmen, Pax and Invicta and species of red and white currants Rovada, Orion and Olin. Among black currants, species Ometa and Ruben had the highest values of total antioxidant activity.

<p><strong>Apstrakt je obrađen tehnologijama za optičko prepoznavanje teksta (OCR).</strong></p><p>Ispitana je antioksidativna aktivnost različito pripremljenih napitaka i fermentativnih tečnosti od čajne gljive, i to prvenstveno praćenjem sposobnosti transformacije i stabilizacije reaktivnih hidroksi-radikala i redukcije stabilnih 1,1-difeniI- 2-pikriIhidraziI (DPPH) radikala. Određeni su i neki od metabolita kombuhe koji deluju kao antioksidanti (vitamini B₂ i C), kao i organske kiseline koje stabilizuju napitak od čajne gljive. Osnovne analitičke tehnike kori&scaron;ćene u radu bile su ESR, HPLC, TLC, spektrofotometrija proizvoda enzimskih reakcija i volumetrija.</p> / <p><strong>Abstract was processed by technology for Optical character recognition (OCR).</strong></p><p>The antioxidant activity of differently prepared beverages and fermentative liquids of tea fungus was examined, primarily by following of ability for transformation and stabilization of reactive hydroxyl-radicals and reduction of stable 1,1- diphenyl-2-picrylhydrazyl (DPPH) radicals. Some of the metabolites of kombucha that act as antioxidants (vitamins B2 and C) and organic acids that stabilize tea fungus beverage were determined. The primary used analytical techniques were ESR, HPLC, TLC, spectrophotometry of products of enzymatic reactions and voIumetry.</p><p>&nbsp;</p>

The first cases of patients with pneumonia which grew into an acute respiratory distress syndrome and caused breathing problems began to appear in December 2019. Coronavirus disease 2019 (COVID-19) is the cause of a global pandemic and it is caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). A complex interplay of factors is responsible for the progression of the disease. Some studies suggest that it promotes oxidative stress and thus may lead to oxidative damage to cells and DNA. The purpose of this study was to observe the relationship between oxidative DNA damage and a critical condition caused by COVID-19 using a comet assay technique. The basic principle of the used method consists in fixation of lymphocytes in an agarose gel, removal of the membrane and cytoplasm of cells, incubation with specific enzymes and electrophoresis. In the process of electrophoresis, negatively charged DNA fragments migrates towards the anode and the cell thus acquires the typical shape of a comet. Comets are visualized using the DNA intercalation dye ethidium bromide. We quantified single - strand breaks and oxidized pyrimidines and purines by using specific enzymes (modification of the method for detecting specific lesions). Results are reported as % tail DNA, thus the percentage of DNA in the...

Вещества, обладающие антирадикальной активностью (АРА) играют ведущую роль в системе защиты организма от свободных радикалов. Общие недостатки известных способов оценки АРА выражаются в том, что измерения проводятся непрямыми методами, что затрудняет количественно оценивать содержание веществ с антирадикальными свойствами. Результаты измерений представляются в относительных единицах, в качестве эталонных веществ чаще всего используются: тролокс, галловая и аскорбиновая кислоты, проявляющие разную АРА, что не позволяет сравнивать результаты между собой. Таким образом, существует необходимость в разработке прямого, безэталонного метода оценки антирадикальной активности. Одним из потенциально возможных решений данной проблемы является метод ЭПР-спектроскопии на модели 2,2-дифенил-1-пикрилгидразил. Цель и задачи исследования. Исследование безэталонным методом оценки антирадикальной активности природных и синтетических антиоксидантов на модели 2,2-дифенил-1-пикрилгидразил с использованием ЭПР-спектроскопии. Отработка методики определения антирадикальной активности на модели ДФПГ методом ЭПР-спектроскопии. Получение и анализ значений антирадикальной активности для ряда веществ с антирадикальными свойствами. Сравнение с результатами полученными методом потенциометрического определения антиоксидантной активности с использованием медиаторной системы. Полученные результаты. Установлены оптимальные условия для проведения анализа. Проведено исследование - новым, безэталонным методом оценки антирадикальной активности, ряда природных и синтетических антиоксидантов. Установлены значения антирадикальной активности ряда природных и синтетических антиоксидантов. Рассмотрены различные варианты механизмов ингибирования свободных радикалов и их зависимость от структуры антиоксиданта. / Substances with anti-radical activity (ARA) play a leading role in the body's defense system against free radicals. General disadvantages of the known methods of evaluating the APA expressed in the fact that measurements are carried out by indirect methods, making it difficult to quantify the content of substances with antiradical properties. The measurement results are presented in relative units, as reference substances are most often used: Trolox, ascorbic and gallic acid, exhibit different ARA, which does not allow to compare the results with each other. Thus, there is a need to develop direct, reference-free method of evaluating anti-radical activity. One possible solution to this potential problem is the method of EPR model 2,2-diphenyl-1-picrylhydrazyl. The purpose and objectives of the study. Study standardless method for assessing the antiradical activity of natural and synthetic antioxidants model 2,2-diphenyl-1-picrylhydrazyl using EPR spectroscopy. Testing methods for determining the anti-radical activity in the DPPH model EPR spectroscopy. Obtaining and analyzing anti-radical activity values for a number of substances with antiradical properties. Comparison with the results obtained by potentiometric determination of antioxidant activity using a mediator system Results. The optimum conditions for analysis. The research - the new reference-free method of evaluating anti-radical activity, a number of natural and synthetic antioxidants. Established values antiradical activity of natural and synthetic antioxidants. Various embodiments of the mechanisms of inhibition of free radicals and their antioxidant dependency structure.