A total of 150 μL of FRAP working solution and 50 μL of test sample were added to each well of a 96-well plate. The absorbance of the reaction mixture was measured at 600 nm after 8 min of incubation. A standard curve was constructed using ferrous sulfate (FeSO4⋅7H2O) as a reference standard, and the results were expressed as nmol Fe+2 equivalent μg−1 dry extract (Benzie and Strain, 1996).