DPPH radical scavenging activity was determined using the
method originally developed by Blois (1958). A portion (0.1 ml)
of the extract solution (1.0 mg/ml DMSO) in a test tube was well
mixed with 3.9 ml of methanol and 1.0 ml of a,a-diphenyl-b-picrylhydrazyl (DPPH) solution (1.0 mM in methanol). The mixture
was kept at ambient temperature for 30 min prior to measurement
of the absorbance at 517 nm (A517 nm). BHA was used as the reference. All measurements were done in triplicate. The scavenging effect was derived following