Bioactives of fruiting bodies and submerged culture mycelia of Agaricus brasiliensis (A. blazei) and their antioxidant properties

Agaricus brasiliensis is a mushroom native from Brazil largely studied due to its polysaccharide contents, particularly beta-glucans. In this study, the phenolics and organic acids contents as well as the antioxidant activities of its fruiting bodies and its mycelia obtained from submerged cultivation were compared. The hydroalcoholic extracts obtained from the fruiting bodies, early stationary mycelia and late stationary mycelia contain at least ten phenolic compounds and ten organic acids. Three phenolic compounds were identified as gallic acid, syringic acid and pyrogallol. Eight organic acids were identified as benzoic, oxalic, malic, acetic, alpha-ketoglutaric, citric, fumaric and trans-aconitic acids. All extracts presented antioxidant properties. The latter were evaluated by four assays: DPPH and ABTS radical scavenging activities, chelating ability for ferrous ions and inhibition of lipid peroxidation. The fruiting body extracts were more effective in the DPPH radical scavenging activity and lipid peroxidation inhibition that the mycelia extracts (P <= 0.05). The mycelia extracts were more effective in the ABTS radical scavenging activity and ferrous ion chelating ability (P <= 0.05). In conclusion, our results show that the mycelia of A. brasiliensis obtained in submerged cultivation can also be, as its fruiting bodies, valuable sources of antioxidant compounds. (C) 2011 Elsevier Ltd. All rights reserved.