nFe
2+
-chelating capacity of the extracts was determined as described byMinotti
and Aust (1987)and modified byPuntel et al. (2005). Briefly, 500 lM of freshly-prepared FeSO4was added to a reaction mixture comprising 0.1 M Tris–HCl (pH 7.4),
0.9% NaCl and the extract or 0.1 M Tris–HCl (blank) or reference (EDTA). After a
5-min incubation at room temperature, 0.35% 1,10-phenanthroline (w/v) was
added and the absorbance at 510 nm was determined.