The metal chelating activity of extract was measured as reported by Dinis, Madeira, and Almeidam (1994). The extract (0.5 mL) was mixed with 50 mL of ferrous chloride and 1.6 mL of methanol was added. After 5 min, the reaction was initiated by the addition of 5 mmol/L ferrozine and the mixture was shaken on vortex. The mixture was incubated at room temperature (25 C) for 10 min. Absorbance of solution was measured at 562 nm on a spectro- photometer. The chelating activity of the extract for Feþ2 was calculated as follows: