where I is the inhibition percentage, Acand Asare the absorbance
values of the control and test samples, respectively.
The sample extract concentration providing 50% inhibition
(EC50) of the DPPH radical was calculated by plotting the
concentration versus inhibition percentage (%). Using the same
procedure, EC50value of Trolox solution was also determined to
compare antioxidant activity of the samples. Antioxidant activity
of samples was also expressed as Trolox equivalent antioxidant
capacity (TEAC).