Abstract: The male flowers of Eucommia ulmoides were extracted by the solvents with different polarities, namely, petroleum ether, ethyl acetate, n-butanol, and water. The contents of total phenols in the obtained extracts were measured, and their antioxidant activities were examined in vitro and compared with those of BHT and VC, which were the two conventional reductants, from the aspects of scavenging rate of DPPH and hydroxyl free radicals, reducing power, and anti-lipid per-oxidation activity, respectively. The results indicated that Eucommia male flower was rich in phenols. The content of phenols in ethyl acetate extract (EE) (393.47 mg ·g^-1) and n-butanol extract (BE) (287.33 mg ·g^-1) were higher than those in water extract (WE) (114.74 mg ·g^-1) and petroleum extract (PE) (105.42 mg ·g^-1). The rates of scavenging DPPH free radical of the EE and BE were 91.55% and 80.32%, respectively, close to those of BHT and VC. The rate of scavenging hydroxyl free radical of BE was relatively higher (80.47%), while the reducing power of EE was higher than those of BHT and VC. The activities of anti-lipid per-oxidation of EE, BE and WE were higher than that of VC. The reducing power, rate of scavenging DPPH free radical and activity of anti-lipid per-oxidation of the extracts were positively correlated to the content of total phenols (R²>0.9), and exhibited significant concentration dependent effect. The relatively higher antioxidant activity of Eucommia male flower demonstrated that it could be developed as a health care beverage.

Key words: Eucommia ulmoides, Eucommia male flower, total phenol, antioxidant activity