Antioxidant interactions among some natural compounds in grapes

Abstract

In this study, the antioxidant interactions between natural grape compounds such as catechin, resveratrol, ascorbic acid, dihydroxyfumaric acid, tartaric acid, citric acid and the ecological preparation ENOXIL were investigated. UV-VIS and Stopped-Flow spectrometric methods were used to evaluate the antioxidant activity using tests such as: DPPH, ABTS, Folin-Ciocalteu, FRAP,according to existing protocols in the literature. It was also investigated how the solvent (water, ethanol), wine matrix and phosphate buffer influence the antioxidant activity of these compounds and the types of antioxidant interactions between them. The results indicated the presence of synergistic effects between ascorbic acid and tartaric, citric, dihydroxyfumaric, ENOXIL and catechin acids. In particular, it was established that the catechin – ascorbic acid mixture exhibits an antioxidant activity that depends on the concentration of the acid. In contrast, the resveratrol - catechin combination shows antagonistic effects, suggesting that these two compounds may cancel each other out in terms of their antioxidant activity. It was also found that, in the wine matrix, the compounds have a significantly higher antioxidant activity than in ethanol. The preparation ENOXIL has been shown to have increased reducing properties in phosphate buffer solution. These results provide a better understanding of how compounds in grapes interact with each other and with the environment in terms of their antioxidant activity. These findings may be useful in the development of effective antioxidant products or dietary supplements.