In thismethod, the ferric complex (Fe+3-TPTZ) is reduced to the ferrous complex (Fe+2-TPTZ) in the presence of an antioxidant and under acidic conditions. Antioxidant activity was expressed as lmol
Fe+2/g extract, using the absorbance obtained for extract and standard ferrous sulphate curve. The reading of the complex was done at 593 nm.