The antioxidant activity of each extract (0.05–20.00 mg/ml in methanol) was determined by the conjugated diene method (Lingnert, Vallentin, & Eriksson, 1979). Reducing power of each extract was determined according to the method of Oyaizu (1986). Scavenging ability of each extract on DPPH radicals was determined on the basis of the method of Shimada, Fujikawa, Yahara, and Nakamura (1992). Chelating ability on ferrous ions of each extract
was determined according to the method of Dinis, Madeira, and Almeida (1994).