Efeitos dos extratos de erva-mate sobre danos oxidativos e sua relação com anti e co-genotoxicidade

Abstract

The consumption of yerba-mate based beverages is part of the habits of the population from South Brazil, Argentina and Uruguay. Its consumption is a cultural symbol linked to sociability and demonstrations of cordiality. Improving the knowledge about the association of yerba-mate consumption with human health can lead to the creation of great economic and social relevant paradoxes. Thus, this research had as objectives: i) to evaluate the capacity of yerba-mate extracts on modulating the redox balance at systemic level in Drosophila melanogaster and at the central nervous system (CNS) in rats; ii) to observe how the extracts can affect genotoxic events related to heterozygosity loss on Drosophila melanogaster wings. Diets with high cholesterol added were used as damage inducers on the study with fruit flies and immobilization with animals. The Somatic Mutation and Recombination Test (SMART) was used to evaluate the relation of the extract with mutagenesis and antimutagenesis. In addition, in the experimental design of this work, were used extracts (mates) obtained mimicking the traditional form of consumption. Thus, in the approaches with fruit flies, extracts obtained by sequential extractions were used. Because of the limitations imposed by the experiment, the crude extract obtained by the conventional manner was used in the animals. In this strand, the evaluation of the effects of the major compound in yerba-mate extracts, the chlorogenic acid (CGA), was also included. The results showed that yerba-mate extracts, in Drosophila melanogaster exposed to hypercholesterolemic diet, are able to increase significantly the capacity to resist the induced stress, improving the redox homeostasis. This was evidenced by the reduction of the levels of lipid peroxidation products, glutathione S-transferase (GST) activity recovery and increase of the insects’ lifespan. In the brain regions: cortex (CTX), hippocampus (HIP) and striatum (STR), the induction of immobilization stress produces damage to lipids and proteins. Mate and CGA were able to mitigate these damages, demonstrating their potential to improve induced stress resistance. This effect was possibly mediated by its antioxidant capacity. To complete, the results obtained for the genotoxic activity showed that mate does not induce damage in Drosophila wings, either by mutational or recombinant processes. Data for the evaluation of the antigenotoxicity indicated that the extracts reduced the frequency of mutant stains in co-treatment. However, they can present genotoxic effects when given after damage. This may be due to its action on modulating detoxifying functions in the organism, related mainly to the P450 cytochrome (CYP). Based on the literature data, this information lead to the assumption that phenolic compounds may cause CYP inhibition, reducing metabolization and drug elimination, which produces accumulation and increased toxicity. Were possible to conclude, by using different experimental models and the study proposals, that yerba-mate has significant antioxidant activity and does not produce genotoxic effect per se, but its relation with antigenotoxicity and xenobiotic metabolization needs to be confirmed by deepened studies focused on this approach.