The total antioxidant activity (TAA) of the freeze-dried extract
was determined by adapting the method used by Govindarajan
et al [15] and Subhasree et al [16] with slight modifications.
In brief, the freeze-dried extract was diluted with
distilled water (60e220 mg/mL). The diluted extract (0.2 mL)
was then mixed with 1.8 mL of reagent (0.6 M sulfuric acid,
28 mM sodium phosphate and 4 mM ammonium molybdate)
in a capped plastic tube. The tube was incubated in a water
bath at 90C for 90 minutes, then cooled down to room temperature.
The absorbance of this solution was measured at
695 nm using a UVeVIS spectrophotometer against a blank.
Ascorbic acid (5e60 mg/mL) was used as the standard. TAA is
expressed as equivalent of ascorbic acid.