2.3.3. Assay of hydroxyl radical scavenging activity
The hydroxyl radical scavenging activity was determined according to the
method of Zhong et al. (2010) with some modifications. The mixture containing
1 ml of sample (0.1–0.5 mg/ml), 1 ml of 9 mM FeSO4 and 1 ml of 0.3% H2O2 in
0.5 ml of 9 mM salicylic acid–ethanol solution was shaken vigorously and incubated
at 37 C for 30 min. Then, the absorbance of the reaction mixture was determined at
510 nm. VC was used as the positive control. The hydroxyl radical scavenging activity
was calculated by the following formula:
Scavenging activityð%Þ¼½1 ðA1 A2Þ=A0 100 ð2Þ