assay The free radical-scavenging activities of crude extract and its four partitioned fractions (petroleum ether fraction, ethyl acetatefraction, n-butanol fraction and water fraction) were measured interms of hydrogen donating or radical-scavenging ability using the stable radical DPPH (Wu et al., 2009). The different con-centrations of the samples in 50% ethanol (100 L) were mixed with 50% ethanol (1.4 mL) and then added to 0.004% DPPH (1 mL,Sigma–Aldrich) in ethanol. The mixture was shaken vigorously and then immediately incubated in darkness. After 70 min, the reactionreached a plateau. The absorbance of reaction solution was deter-mined in a UV-Vis spectrophotometer (UNICO, Shanghai, China) to monitor absorbance at 517 nm. Ascorbic acid (Sigma–Aldrich), a stable antioxidant, was use das a positive reference. The DPPH radical-scavenging activity inpercen tage of sample was calculated as follows: