Objective: To establish a method based on the anti-oxidant biological effects

which could be used to evaluate and control the quality of the anti-oxidation effective fraction of Jiangzhining. Method: The IC50 value and anti-oxidation intensity were measured by DPPH free radical scan

and vitamin C served as a positive control. Result: The IC50 values were 7.43 mg·L-1 and 11.50 mg·L-1 for vitamin C and the effective fraction of Jiangzhining respectively. The anti-oxidation intensity of the effective fraction of Jiangzhining was 0.646. There was no significant difference among the different batches of samples prepared from different batches of herbs. Conclusion: The method was efficient and accurate

and could be used to determine the anti-oxidation intensity and evaluate the quality of Jiangzhining.