2.5. DPPH radical-scavenging activity
DPPH radical-scavenging activities of ethanol and water extracts
were determined by the method of Hu et al. (2009). Different
concentrations (0.12–2.00 mg/ml) of sample and BHT (as positive
control) were prepared. 100 ll of each sample/standard solution
was mixed with 100 ll of DPPH solution. Then, the mixture was
incubated at RT for 30 min. Absorbance of the solution was
measured at 517 nm. The control (instead of sample and standard)
was prepared according to same procedure. DPPH radicalscavenging
activity was calculated by using the following
equation:
DPPH radical-scavenging activity ð%Þ
¼ fðC DÞ ðA BÞ=ðC DÞg 100;
where, A = absorbance of DPPH + sample/standard, B = absorbance
of sample/standard + methanol, C = absorbance of DPPH + DW/
methanol and D = absorbance of methanol + DW.