1ml of plant extract, 2.5 ml phosphate buffer (of 0.2 M, pH 7)
and 1% potassium ferricyanide (2.5 ml) were mixed and incubated
at 50 ◦C for 30 min. To the solution, 2.5 ml of 10% trichloroacetic
acid was added and centrifuged at 6500rpm for 10 min. Distilled
water (2.5 ml) and 0.5 ml of 0.1% FeCl3 were added to 2.5 ml of
the supernatant. The absorbance of the solution was measured at
700nm using UV–visible spectrophotometer. The reducing ability
of the plant was evaluated in terms of percentage by relating to the
standard, FeSO4