Free radical scavenging activity and phenolic contents of hydroalcoholic extracts from basidoma and mycelial mass of Agaricus brasiliensis

Agaricus brasiliensis (A. blazei), a medicinal mushroom originary from Brazil, is largely studied due to the antitumoral and immunomudalatory activities of its β-glucans. Little is known about its phenolic content and antioxidant properties. The objective of this study was to compare antioxidant activity and phenolic content of hydroalcoholic extracts from the basidioma and the mycelial mass of A. brasiliensis. The antioxidant activity was evaluated using DPPH (1,1-dyphenyl-2-picryl-hydrazine). Total phenolics were quantified by the Lowry reagent and the main phenolics found in the hydroalcoholic extracts were identified by HPLC. The total phenolic contents were 19.49, 43.12 and 54.40 microg/ml, respectively, for the basidoma, young mycelial mass and old mycelial mass. The extract concentrations yielding 50% free scavenging activity measured using DPPH were 6.0, 10.5 and 12.0mg/ml, respectively for the basidoma, young mycelial mass and old mycelial mass. Analysis by HPLC showed that gallic acid, syringic acid, benzoic acid and pyrogallol were the main phenolic compounds in all hydroalcoholic extracts. Syringic acid was the main phenolic compound in the basidioma extract while pyrogallol was the main phenolic compound in the young and old mycelial mass extracts. The data obtained show that the antioxidant activity of A. brasiliensis is associated with its phenolic content and both basidoma and mycelial mass are useful sources of antioxidant compounds.

Acknowledgements: Financial support: CNPq, Fundo Paraná and Fundação Araucária.