The FRAP assay was determined, following the method
of Chu, Chang, and Hsu (2000) with modifications. A
0.1M potassium phosphate buffer (pH 6.6) (2.5 ml) and
1% w/v potassium ferricyanide (2.5 ml) were mixed with
1ml of extracts of varying dilutions. The reaction mixture
was incubated at 50 1C for 20 min, after which 10% w/v
trichloroacetic acid (2.5 ml) was added. 2.5 ml of water and
0.5 ml of 0.1% w/v FeCl3 were then added to 2.5 ml of the
reaction mixture. The solution was incubated at ambient
temperature for 30 min for colour development. The
absorbance was then measured at 700 nm. The FRAP
value was expressed in mg GAE/g.