171 resultados para Cromatografia.Antioxidante


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Pós-graduação em Medicina Veterinária - FCAV

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The main objectives of this work were to evaluate the antioxidant activity and to determine of an ethanolic ginger extract total phenolic compounds concentration, as well as verifying its behavior by means of the oxidative stability, when added to refined soybean oil in concentrations of 0, 500, 1000, 1500, 2000 and 2500 mg/kg. The maximum antioxidant activity and EC50, concentration of the extract to achieve 50% of the antioxidant activity, value determined by free radical DPPH method were 79.1% and 42.6 g/mL, respectively. The total phenolic compounds concentration, determined to Folin-Ciocalteu method, was 251 mg/g. The induction period of the samples increased according to the augment of the extract concentration in the oil when evaluated using oxidative stability through the Rancimat equipament. It was possible to conclude that the ginger extracts possess effective action against the lipid oxidation and can be applied in foods as natural antioxidant.

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Living organisms are constantly subjected to the action of free radicals, which are one of the causes of oxidation reactions, because they have on free electron, what makes it very reactive. They are products of organism reactions or they are produced by exogenous factors, such as tobacco. Fatty acids are the most vulnerable target, and may suffer lipid peroxidation, what affects the cell structure. Cardiovascular diseases, cancer and diseases of aging are occurrence of these reactions in the organism related. The aliments are also subjected to suffer oxidation reactions, what make them unfit for consumption and decreasing the useful life. Synthetics antioxidants are used as aliments preservatives, but they present some toxicity for the organism. Studies for the utilization of natural antioxidants have gained more importance in recent decades, due to the conservation potential and low toxicity. Phenolics compounds are largely present at the vegetable kingdom and they present high antioxidant potential due to the neutralization and kidnapping of free radicals capacity. These compounds are used by the industry at the aliments conservation, specially the phenolics acids. The consumption of aliments rich in phenolic compounds, such as teas, wines and fruits are low incidence of degenerative diseases related. This study consists in a bibliographic revision that covers these compounds importance in diet and at the food conservation, and the methodologies and difficulties in the extraction process due to variety of molecules of this group.

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There are cassava varieties that present compounds as carotenoids, beta-carotene, lycopene and minerals important for human and animal health. The present study evaluated the antioxidant activity of the white, yellow and pinkish varieties of Manihot esculenta, by mean of the DPPH test and by the ferrous ion-chelating activity. Furthermore, the total phenols, carotenoids, beta-carotene, lycopene and zinc contents were also determined. Utilizing the DPPH test it was possible to find that extracts of boiled samples presented higher antioxidant activity (89.53% - pinkish) in comparison to the fresh samples (1.97% - white). For the ferrous ion-chelating test, the highest activity was found for the boiled pinkish variety extract (63.43%) and the lowest was for fresh yellow extract (17.34%) the white sample did not present activity. The highest concentration of total phenols and zinc content was obtained for the boiled pinkish variety extract 136.12 mg EAG/g of extract and 0,811ppm, respectively, in the concentration of 1000 µg/mL. The pinkish variety presented also higher quantity of pigments, including carotenoid (29.40 µg/g), beta-carotene (9.14 µg/100g) and lycopene (68.92%). According to the results obtained in this study it was possible to conclude that the yellow and pinkish varieties of M. esculenta present quantity of phenolic compounds and minerals sufficient to attribute the antioxidant activity and may thus contribute to reduce oxidative damage and be used as nutraceuticals or directly ingested in the diet to maintain good health.

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Alimentos ricos em compostos antioxidantes têm sido difundidos como protetores à saúde devido a sua associação com a redução de fatores de risco para doenças crônicas, como o diabetes mellitus tipo 2, doenças cardiovasculares, entre outras. Tem sido sugerido que as flavanonas cítricas apresentam potencial para reduzir o estresse oxidativo em estados de inflamação crônica, como, por exemplo, na obesidade. O objetivo deste estudo foi avaliar a atividade antioxidante da hesperidina, eriocitrina e eriodictiol em camundongos submetidos a uma dieta hiperlipídica, indutora da obesidade. Foram utilizados 50 camundongos C57BL/6J machos divididos aleatoriamente em 5 grupos (n=10 cada), sendo: (1) grupo controle, tratado com dieta padrão; (2) grupo tratado com dieta hiperlipídica; (3) grupo tratado com dieta hiperlipídica e hesperidina (100 mg/kg peso); (4) grupo tratado com dieta hiperlipídica e eriocitrina (200 mg/kg peso); e (5) grupo tratado com dieta hiperlipídica e eriodictiol (200 mg/kg peso). O estudo teve duração de 30 dias e cada grupo recebeu o composto específico juntamente com a dieta, com base na média de ingestão diária e peso corporal. Foram avaliados a glicose, triglicerídeos, colesterol total, HDL-C e LDL-C no soro através de métodos enzimático-colorimétricos, a capacidade antioxidante pelo método ABTS, e o estresse oxidativo no soro e fígado pelo método de TBARS. Os camundongos alimentados com dieta hiperlipídica tiveram aumento da glicose (20%), colesterol total (36%), LDL-C (55%) e peroxidação lipídica hepática (44%), quando comparados aos animais controle. O grupo suplementado com hesperidina reduziu 28% LDL-C em relação à dieta hiperlipídica. Todos os grupos suplementados com flavanonas apresentaram aumento da capacidade antioxidante total no soro (≈ 9,3 %), e redução do TBARS no fígado (≈ 64%). Além disso, os grupos suplementados com eriocitrina e eriodictiol reduziram os níveis de ...

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Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

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Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

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O suco de laranja é um alimento rico em substâncias antioxidantes, como os flavonoides cítricos, vitamina C e carotenoides, que podem reduzir o estresse oxidativo que está relacionado à gênese das doenças cardiovasculares, diabetes e câncer. No entanto, o processamento da laranja para obtenção do suco interfere no tipo e quantidade dos compostos antioxidantes, podendo comprometer as ações esperadas. O objetivo deste trabalho foi avaliar a atividade antioxidante do suco de laranja, comparando os resultados após a ingestão aguda do suco de laranja fresco e do suco de laranja pasteurizado comercialmente em indivíduos adultos saudáveis. Cada voluntário foi submetido a dois tratamentos: ingestão aguda de suco de laranja fresco e, após intervalo de 30 dias, ingestão aguda de suco de laranja pasteurizado. Nos dois tratamentos foram colhidas amostras de sangue dos indivíduos antes e após a ingestão do suco de laranja. O efeito antioxidante total foi mensurado pelo ensaio do radical ABTS+ (2,2'azinobis (3-etilbenzenotiazolina 6-sulfônico) e pelo ensaio de TBARS (substâncias reativas ao ácido tiobarbitúrico) nas amostras de sangue. Observou-se um aumento de 2,2% na capacidade antioxidante do sangue a partir de 4 horas após a ingestão do suco de laranja fresco e que se manteve estável até 24 horas do consumo (p<0.05). Já com a ingestão do suco de laranja pasteurizado, a capacidade antioxidante se manteve estável e equivalente ao suco de laranja fresco nas primeiras 4 horas, mas aumentou 1,4% após 8 horas, permanecendo neste nível até as 24 horas seguintes (p<0.05). Após a ingestão do suco fresco, os níveis de peroxidação lipídica, diminuíram 27% nas primeiras 4 horas. Porém, a partir das 8 h retornaram ao valor inicial. Os resultados após o consumo do suco pasteurizado mostraram uma redução da peroxidação lipídica em 18% a partir das 4 horas e 8 h (p<0.05), e esta redução se acentuou (27%) às 24 h ...

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Sustainability is the ability of human beings interact with the world, preserving the environment to not compromise the natural resources of future generations. This is the main goal of Green Chemistry, which is based on twelve basic principles. One of its branches, the Green Analytical Chemistry, apply these principles in their techniques, such as Green Chromatography. The aim of this study was to do a brief literature review on some chromatographic techniques (Gas Chromatography, High Performance Liquid Chromatography, High Temperature Liquid Chromatography, Ultra Pressure Liquid Chromatograph, Micro Liquid Chromatography and Super Critical Chromatography) and measure their impact on the environment

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Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

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Pós-graduação em Biociências - FCLAS

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Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

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Phenolic compounds and antioxidant capacity are defense mechanisms of plants against the oxidative stress damage. Phenolic compounds are synthesized through the phenylpropanoid pathway, where the enzyme phenylalanine-ammonia-lyase plays a key role and it is influenced by light and photoreceptors such as phytochromes. The present research aims to evaluate the phenolic compounds content and antioxidant capacity of the wild Micro-Tom (MT) cultivar tomato fruits and its photomorphogenic mutant tomato plants high pigment 1 (hp1), super responsive to events mediated by light, and aurea (au), quantitative phytochrome deficient. Twenty mature fruits of each genotype (MT, hp1, au) were used in triplicate for analyses. To quantify the total phenolic compounds the Folin-Ciocalteu method was used and the antioxidant capacity was analyzed by Ferric Reducing Antioxidant Power (FRAP) and 2,2-diphenyl-1-picrylhydrazyl (DPPH) methods. The hp1 mutant presented the highest total phenolic compounds content and higher antioxidant capacity than wild cultivar (MT) and au mutant, which did not differ significantly from MT cultivar.