Reducing Capacity of Plant Extracts

To check reducing capacity different concentrations of the plant extracts (100–1000 μg mL^-1) were mixed with 1 mL phosphate buffer (0.2 M, pH 6.6). Thereafter 1 mL of K₃Fe(CN)₆ (10 mg mL^-1) was added to the reaction and incubated at 50°C in water bath (Julabo, Germany). After 20 min of incubation, 1 mL trichloroacetic acid (100 mg L^-1) was added to terminate the reaction. Reaction mixtures were cooled at room temperature, centrifuged at 7000 x g for 10 min and the supernatant was collected. In the next step 1 mL supernatant was mixed with 0.2 mL freshly prepared FeCl₃ (0.1% w/v), incubated for 10 min at room temperature, absorbance was measured at 700 nm. Ascorbic acid was used as standard [49 (link), 51 ].