The method reported by Shimada, Fujikawa, Yahara, and
Nakamura (1992) was adapted to measure free radical scavenging
capability. To each 1 mL of sample solution at different concentrations (0.31–5.00 mg/mL), 1 mL of freshly prepared methanolic
dimethyl sulfoxide (DMSO) solution of DPPH (0.325 mM) was
added. This was mixed well and then left standing for 30 min at
room temperature in the dark. The absorbance ofthe resulting solution was recorded at 517 nm. BHA was used as a reference material.
All tests were preformed in triplicate. Scavenging activity was calculated as follows: