Chelating ability on ferrous ions by metal chelatin gassay Chelating ability of extract was measured according to the method of Decker and Welch (1990). A 1 mL sample was sequentially mixed with 3.7 mL methanol, 0.1 mL 2 mM FeCl2, and 0.2 mL 5 mM ferrozine. The mixture was shaken vigorously and left to stand for 10 min at room temperature. The absorbance was measured at 562 nm using spectrophotometer, and EDTA-2Na (ethylenediaminetetraacetic acid 2 sodium) was used for comparison. The chelating ability was calculated by using the formula: scavenging ability (%)=[(absorbance562nmof control − absorbance562nmof sample)/ absorbance562nmof control]×100.