Antioxidant properties in the oyster mushrooms (Pleurotus spp.) and split gill mushroom (Schizophyllum commune) ethanolic extracts

Ethanolic extracts of oyster mushrooms (Pleurotus pulmonarius, P. ostreatus, P. djamor var. djamor and P. djamor var. roseus) and the split gill mushroom (Schizophyllum commune) were successfully investigated for their antioxidant properties. The study was carried out to determine the capability of the extracts to scavenge 2,2-diphenyl-1-picrylhydrazyl (DPPH) radicals, to determine its reducing ability towards ferricyanide complex (FRAP assay) and to determine the concentration of total phenolic content (TPC) and total flavonoids content (TFC) in the macrofungi ethanolic extracts. Inhibition concentration at 50% (IC50) for each extract to scavenge DPPH radicals was detected from 2.75 mg/ml to 12 mg/ml where S. commune from the fourth flush showed the lowest IC50 value among all tested mushrooms. The greatest ability to reduce ferricyanide complex to ferrous form was observed in P. djamor var. djamor at concentration 10 mg/ml in both first (1.23 +/- 0.02) and second flushes (1.23 +/- 0.00). Meanwhile, the highest TPC was determined in P. djamor var. djamor extract (51.94 +/- 0.04 mg TAE/g dry weight of extract) whereas S. commune gave highest reading of total flavonoid content in TFC assay (29.80 +/- 0.27 mg QE/g dry weight of extract). All the mushroom samples showed appreciable antioxidant properties which therefore, can be promoted as natural antioxidant preference in food and pharmaceutical industries.