1.5.3. Total antioxidant capacity (TAOC)
The basis for this assay was the reduction of Molybdenum VI to Molybdenum (V) and formation of a green phosphate/Molybdenum (V) complex in acidic conditions (Prieto et al ., 1999). Different concentrations (25, 50, 100, 200 and 400 μg/ml) were prepared by dissolving the extracts/fractions in distilled water. 0.3 ml of the extract/fraction mixed with 3 ml of reagent. Reagent solution comprises of mixture of various reagent like sulfuric acid (0.6 M), sodium phosphate (28 mM) and ammonium molybdate (4 mM). After mixing both sample and reagent solution, mixture was incubated for 90 min (95˚C) after covering the test tubes with aluminium foil. Absorbance was recorded at 695 nm after cooling the solution at room temperature, against blank. Similar procedure was carried out with ascorbic acid which is used as standard. The total antioxidant activity was expressed as absorbance of the sample. A higher absorbance value would indicate a higher antioxidant activity (Li and Wang, 2011).