Antioxidant activity of the sample was determined using the
ferric reducing antioxidant power (FRAP) assay of Benzic and Strain
(1996)
as a measure of ‘‘Antioxidant Power.’’ The working FRAP reagent
was prepared by mixing 10 ml of 300 mM acetate buffer,
1 ml of 10 mM TPTZ (2,4,6-tripyridyl-s-triazine) in 40 mM hydrochloric
acid and 1 ml of 20 mM ferric chloride. The 100 ll
(0.1 ml) of extract were added to 3.9 ml of freshly prepared FRAP
reagent and mixed thoroughly, and a reading was taken at
593 nm in a UV–Vis spectrophotometer. A standard curve was prepared
using different concentrations of trolox. The results were expressed
as micromoles of trolox equivalents per gramme fresh
weight.