ˇ@ˇ@DPPH(1,1-Diphenyl-2-picrylhydrazyl) is a stable free radial with red color(absorbed at 517nm). If free radials have been scavenged, DPPH will generated it's color to yellow. This assay uses this character to show herbs free radical scavenging activity.

ˇ@Herb extracts were mixed with DPPH(0.1mM) in ethanol solution. After 20 min incubation at room temperature, read the absorbance at 517 nm.
ˇ@The inhibitory percentage of DPPH was calculated according to the following equation:

ˇ@ˇ@ˇ@ˇ@ absorbance(cont)-absorbance(sam)
%inhibition=---------------------------------------ŁA100%
ˇ@ˇ@ˇ@ˇ@ˇ@ˇ@ˇ@ˇ@ˇ@absorbance(cont)