2.3.5. Assay of H2O2 scavenging activity
The H2O2 scavenging activity was determined according to the method of Ruch
et al. (1989) with some modifications. The mixture containing 1 ml of sample (0.1–
2 mg/mL), 2.4 ml of phosphate buffer (0.1 M, pH 7.4) and 0.6 ml of H2O2 solution
(40 mM) was shaken vigorously and incubated at room temperature for 10 min.
Then, the absorbance of the reaction mixture was determined at 230 nm. VC was
used as the positive control. The H2O2 scavenging activity was calculated as follows:
Scavenging activityð%Þ¼½1 ðA1 A2Þ=A0 100 ð4Þ
where A0 is the absorbance of the control (water instead of sample), A1 is the absorbance
of the sample, and A2 is the absorbance of the sample only (phosphate buffer
instead of H2O2 solution). The IC50 value represented the concentration of the compounds
that caused 50% inhibition of H2O2.
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