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Métodos para a determinação do potencial antioxidante dos frutos
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As polpas e os extratos de frutos têm sido identificados como fontes potenciais de grande atividade antioxidante. Tendo em conta que o stress oxidativo foi descrito como estando envolvido em patologias degenerativas, tais como o cancro, Parkinson, Alzheimer, doenças cardiovasculares e doenças autoimunes, atualmente efetuam-se diversos estudos, a fim de verificar e comprovar a atividade antioxidante de frutos e de outros alimentos na prevenção dessas doenças.
Para avaliar a atividade antioxidante dos frutos, podem ser utilizados, individualmente ou em conjunto, diversos métodos. Neste contexto, apresenta-se uma revisão dos métodos mais utilizados na avaliação do potencial antioxidante dos frutos, nomeadamente por remoção de um radical peroxil (ORAC, Oxygen Radical Absorbance Capacity e TRAP, Total Reactive Antioxidant Potential), pela capacidade de redução de um metal (FRAP, Ferric Reducing Antioxidant Power e CUPRAC, Cupric ion Reducing Antioxidant Capacity), pela capacidade de remoção de um radical orgânico (ABTS, método do ácido 2,2'-azino-bis-3-etilbenzotiazolina-6-sulfónico e DPPH, método do 2,2-difenil-1-picril-hidrazil) e pela quantificação de produtos formados durante a oxidação de lípidos (TBARS, Thiobarbituric Acid Reactive Substances, oxidação das lipoproteínas de baixa densidade (LDL, Low Density Lipoprotein) e co-oxidação do β-caroteno). Apresentam-se também as vantagens e as desvantagens de cada um dos métodos.
Fruit pulp and fruit extracts have been identified as potential great sources of antioxidant activity. Although oxidative stress has been previously described as being involved in degenerative diseases such as cancer, Parkinson's, Alzheimer's, cardiovascular diseases and autoimmune diseases, there are currently several studies being performed in order to verify and confirm the antioxidant activity of fruits and other foods for the prevention of these diseases. Several methods may be used, individually or together, to evaluate the antioxidant activity in fruits. In this report, the author comprehensively reviews the literature regarding the methods used in the evaluation of the fruit antioxidant potential, namely by removal of a peroxyl radical (ORAC, Oxygen Radical Absorbance Capacity and TRAP, Total Reactive Antioxidant Potential), by the capacity of reduction of a metal (FRAP, Ferric Reducing Antioxidant Power and CUPRAC, Cupric ion Reducing Antioxidant Capacity), by the ability to remove an organic radical (ABTS, 2,2′-azino-bis-3-ethylbenzthiazoline-6-sulphonic acid method and DPPH, 2,2- diphenyl-1-picril – hydrazyl method) and by the quantification of the products formed during the oxidation of lipids (TBARS, Thiobarbituric Acid Reactive Substances, LDL oxidation and Co-oxidation of β-carotene). The author also presents advantages and disadvantages of each method.
Fruit pulp and fruit extracts have been identified as potential great sources of antioxidant activity. Although oxidative stress has been previously described as being involved in degenerative diseases such as cancer, Parkinson's, Alzheimer's, cardiovascular diseases and autoimmune diseases, there are currently several studies being performed in order to verify and confirm the antioxidant activity of fruits and other foods for the prevention of these diseases. Several methods may be used, individually or together, to evaluate the antioxidant activity in fruits. In this report, the author comprehensively reviews the literature regarding the methods used in the evaluation of the fruit antioxidant potential, namely by removal of a peroxyl radical (ORAC, Oxygen Radical Absorbance Capacity and TRAP, Total Reactive Antioxidant Potential), by the capacity of reduction of a metal (FRAP, Ferric Reducing Antioxidant Power and CUPRAC, Cupric ion Reducing Antioxidant Capacity), by the ability to remove an organic radical (ABTS, 2,2′-azino-bis-3-ethylbenzthiazoline-6-sulphonic acid method and DPPH, 2,2- diphenyl-1-picril – hydrazyl method) and by the quantification of the products formed during the oxidation of lipids (TBARS, Thiobarbituric Acid Reactive Substances, LDL oxidation and Co-oxidation of β-carotene). The author also presents advantages and disadvantages of each method.
Descrição
Trabalho Final de Mestrado Integrado, Ciências Farmacêuticas, Universidade de Lisboa, Faculdade de Farmácia, 2016
Palavras-chave
Atividade antioxidante Stress oxidativo Doenças degenerativas Frutos Métodos (ORAC, TRAP, FRAP, CUPRAC, ABTS, DPPH, TBARS) Mestrado Integrado - 2016