Antioxidant properties of various extracts from Hypsizigus marmoreus

Hypsizigus marmoreus (Peck) Bigelow (Tricholomataceae) is an edible mushroom currently available in Taiwan. The ethanolic, cold water and hot water extracts were prepared and their antioxidant properties studied. At 5 mg/ml, various extracts exhibited moderate antioxidant activities of 38.6–65.2% and their EC50 values were 3.74–6.59 mg/ml. At 5 mg/ml, the cold water extract showed a high reducing power of 0.99. With regard to the scavenging ability on 1,1-diphenyl-2-picrylhydrazyl radicals, extracts were effective in the order: ethanolic > hot water ≫ cold water extracts. With regard to the effect on hydroxyl radicals, the cold water extract was more effective than the hot water extract. EC50 values for chelating ability on ferrous ions for ethanolic, cold water and hot water extracts were 3.19, 0.37 and 0.40 mg/ml, respectively whereas values for chelating ability on cupric ions were 4.42–6.63 mg/ml. Total phenols were the major naturally occurring antioxidant components found and were in the order: cold water > hot water > ethanolic extracts. Based on EC50 values, the various extracts from H. marmoreus were effective antioxidants.