100 μL sample solution (5, 10, 30, 50, 100 and 200 μg/mL) were added into wellplate and than mixed with 100 μL of ethanol solution and 100 μL of 1,1-diphenyl-2-picrylhydrazyl (DPPH) radicals solution. The mixture was incubated for 30 minutes in room temperature, and than the absorbance was measured using microplate reader at 517 nm. α-tocopherol was used as a positive control. The capacity to scavenge the DPPH radical was calculated by the equation : [(A-B)/A] × 100 %; whereas A is the absorbance of the negative control (DPPH plus ethanol) and B is the absorbance of the sample. The activity was expressed as IC50 (the concentration of sample required to scavenge 50 % of DPPH free radicals).