EC50 value (mg extract/mL) is the effective concentration at
which DPPH radicals were scavenged by 50%; and ferrous ions were
chelated by 50% and were obtained by interpolation from linear
regression analysis. Ascorbic acid and butylated hydroxyanisole
(BHA, SigmaeAldrich) were used for scavenging ability comparison
whereas ethylenediaminetetraacetic acid (EDTA, SigmaeAldrich)
was used for chelating ability comparison.