where Acontrol was the absorbance of the control reaction (containing all
reagents except the test compound), and Asample was the absorbance of test compound.
The antioxidant activity was expressed in term of IC50 (50 percent of inhibition
concentrations). The IC50 values were obtained from linear regression of the percentage
(%) inhibition versus various concentrations of the solution of test substances plot.
All measurements were taken in triplicate and the mean values were calculated.