Estudo do potencial antioxidante de diferentes classes de moléculas isoladas de mel e própolis em células de Saccharomyces cerevisiae

Abstract

Honey and propolis are produced by bees from the nectar and sap collected from plants. In the process, the phenolic compounds derived from secondary metabolism of plants are incorporated into the products mentioned. Honey and propolis samples from multiple regions have been characterized and phenolic compounds can be divided into: hydroxybenzoic acid derivatives, hydroxycinnamic acid derivatives, flavonoids and glycosylated flavonoids. In the literature, there is no consensus among the authors about the values for in vitro antioxidant activity. Moreover, these methods do not represent physiological conditions such as concentration of substrates and metabolites interaction. The yeast Saccharomyces cerevisiae is an alternative tool for a biological assays, since it is similar to mammalian cells. The main goal of this study is to compare the antioxidant potential of different phenolic compounds classes using representatives morin, rutin, chlorogenic acid and syringic acid in control strains (BY4741) and mutant (sod1 and gsh1) of S. cerevisiae. They were evaluated in dose-dependent toxicity, stress tolerance, and lipid peroxidation. All tested phenolic compounds were effective in reducing intracellular oxidative damage, especially the chlorogenic acid in the control strain. When compared to stressed cells, it promoted 75% increase on cell survival rates, compared with 57% on average for the other treatments; and 60% decrease in levels of lipid peroxidation, compared to reductions close to 47% with other treatments. In mutant strains, all compounds presented similar results. Thus, two components of the class hydroxycinnamic acid, caffeic acid and caffeic acid phenethyl ester (CAPE) were tested comparatively. Both acted as an antioxidant in S. cerevisiae, however CAPE was the most toxic substance promoting the most significant increase on reduced glutathione levels among hydroxycinnamic derivatives. This result supports some related research that claims phenolic compounds protectection is related to activation of the antioxidant system as xenobiotic action of these substances