Antioxidant properties of methanolic extracts from Grifola frondosa, Morchella esculenta and Termitomyces albuminosus mycelia

Three species of mushroom mycelia are commercially available in Taiwan, namely Grifola frondosa (maitake), Morchella esculenta (morel), and Termitomyces albuminosus (termite mushroom). Methanolic extracts were prepared from these three mycelia and their antioxidant properties were studied. Methanolic extracts from the three mycelia showed high antioxidant activities (85.4-94.7%) at 25 mg ml(-1). Reducing powers of the three methanolic extracts were 0.97-1.02 at 25 mg ml(-1). Scavenging effects on 1,1-diphenol-2-picrylhydrazyl radicals were 78.8-94.1% at 10 mg ml(-1). These three mycelia showed no scavenging effect on hydroxyl radicals. Chelating effects on ferrous ions were high (90.3-94.4%) at 10 mg ml(-1). Total phenols were the major naturally occurring antioxidant components found in methanolic extracts. Contents of ascorbic acid and tocopherols were similar for these three mycelia. All EC50 values were below 10 mg ml(-1), indicating that the three mycelia had good antioxidant properties except for the scavenging effect on hydroxyl radicals. (C) 2003 Elsevier Ltd. All rights reserved.