Method of Chun et al. (2008a, 2008b) with minor modification was used to evaluate the DPPH scavenging activity.
DPPH ethanol solution (1.0 104 mol/L) of 8 mL was mixed with 2 mL sample or 16.52 mol/L ethanol (blank control) with fully shaken, kept in the dark for 30 min reaction at room temperature, and centrifuged at 351 g for 10 min at room temperature.