Free radical scavenging activity were measured by using the 2,2-
diphenyl-1-picrylhydrazil (DPPH•) according to a modified method
by Wu et al. (2006). Sample extracts (100 l) were added into 3.9 ml
of DPPH reagent (prepared with 24 mg of DPPH/L of methanol).
The percentage of DPPH scavenging activity is expressed by the
following formula,