Análise de compostos fenólicos e avaliação da atividade antioxidante de extratos hidroalcoólicos de basidiomicetos

Abstract

Mushroom extracts have received attention for their accessibility, safety and health promotion. This project aimed for the cultivation of basidiomycetes for the extraction of bioactive compounds in hydroalcoholic solutions and evaluation of the extracts’ antioxidant activity, as well as the evaluation of different extraction conditions and storage on the amount of phenolic compounds present. For this, solutions were evaluated with different proportions of ethanol/water and solute/solvent through an experimental delineation, 3x2 factorial. The fungal biomass was first lyophilized to be later subjected to water-alcohol extraction. The extracts were tested to evaluate the content of phenolic compounds, as well as their decay after 24 hours of storage. They were evaluated for the presence of phenolic compounds by the Folin-Ciocalteu method and their antioxidant activity was determined by ABTS [2,2'-azino-bis(3- ethylbenzothiazoline-6-sulphonic acid)] and DPPH [2,2-diphenyl-1-picrylhydrazyl] radical scavenging. The Pleurotus ostreatus mushroom showed the highest amount of phenolic compounds extracted from its matrix, with a value of 2,34% of its dry weight, or 23,40 mg Gallic Acid Equivalents per g of dry sample. The antioxidant activity of Pleurotus ostreatus was also the highest observed, with a value of 28% DPPH radical inhibition and 38% ABTS radical inhibition. The mushroom extract which had the lowest decay to its phenolic compounds was the Pleurotus djamor mushroom, whilst the Pleurotus ostreatus mushroom, although having shown the highest phenolics content, also showed the highest decay over time.