2.6. Determination of total antioxidants

The total antioxidant capacity of the extracts was determined with the phosphomolybdate method using CA as a standard as described by Prieto et al. (Prieto et al., ¹⁹⁹⁹). The assay is based on the reduction in Mo (VI) to Mo (V) by samples and formation of green‐colored phosphate/Mo(V) complex at acidic pH. 0.5 ml of samples/standard at different concentrations (6.25–100 μg/ml) was mixed with 3 ml of reaction mixture containing 0.6 M sulfuric acid, 28 mM sodium phosphate, and 1% ammonium molybdate into the test tubes. The test tubes were incubated at 95°C for 10 min to complete the reaction. The absorbance was measured at 695 nm using a spectrophotometer against blank after cooling at RT. CA was used as standard. The absorbance values of the samples were 0.010–0.743 at the concentrations ranged from 6.25 to 100 μg/ml, respectively. The absorbance values of standard CA were 0.049–0.993 at the concentrations ranged from 6.25 to 100 μg/ml, respectively. A typical blank solution contained 3 ml of reaction mixture, the appropriate volume of the same solvent used for the samples/standard was incubated at 95°C for 10 min, and the absorbance was measured at 695 nm. Increased absorbance of the reaction mixture indicates increased total antioxidant capacity.