The ferricyanide-reducing antioxidant activity of the methanol and aqueous extracts was determined using [29 (link)], method with minor modifications. Potential antioxidant interacts with a colourless Fe3+ complex to reduce it into intense blue Fe2+, which is the basis of the ferric-reducing antioxidant power assay (FRAP) [30 (link)].
Exactly 1 ml of the test solutions or L-Ascorbic acid was combined with 2.5 ml of 0.03 M potassium ferricyanide and 2.5 ml of phosphate buffer (0.2 M, pH 6.6). The concentrations of the extract solution or L-Ascorbic acid ranged from 0.32 μg/ml to 1000 μg/ml. The mixtures were then incubated in a water bath at 50 ℃ for 20 min. After cooling 2.5 ml of 0.6M Trichloroacetic Acid (TCA) was added to each of the test solutions. To an aliquot of 2 ml of each solution, 0.5 ml of FeCl3 solution (0.01%) and 2 ml of distilled water were added. The absorbance of the test solutions was measured at 700 nm by a double-beam Uv Vis spectrophotometer [29 (link)].
Exactly 1 ml of the test solutions or L-Ascorbic acid was combined with 2.5 ml of 0.03 M potassium ferricyanide and 2.5 ml of phosphate buffer (0.2 M, pH 6.6). The concentrations of the extract solution or L-Ascorbic acid ranged from 0.32 μg/ml to 1000 μg/ml. The mixtures were then incubated in a water bath at 50 ℃ for 20 min. After cooling 2.5 ml of 0.6M Trichloroacetic Acid (TCA) was added to each of the test solutions. To an aliquot of 2 ml of each solution, 0.5 ml of FeCl3 solution (0.01%) and 2 ml of distilled water were added. The absorbance of the test solutions was measured at 700 nm by a double-beam Uv Vis spectrophotometer [29 (link)].
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