Objective: To study the antioxidant activity of 6 compounds isolated from Erigeron breviscapus. Method: Compounds were isolated and acquired from E. breviscapus through the methods of organic solvent extraction and chromatography

and identified by the spectrum of NMR(nuclear magnetic resonance). The scavenging activities of all these compounds against 1

1-diphenyl-2-picrylhydrazyl radical (DPPH) radicals

2

2'-amino-di(2-ethyl-benzothiazoline sulphonic acid-6) ammonium salt (ABTS) radicals

O2-·and·OH radicals were evaluated by in vitro method and compared with Vc as positive control. Result: All the six compounds have scavenging capability against DPPH radicals

ABTS radicals

O2-·and·OH radicals and have a good dose-responses relationship with the concentration. The differences between the free radical scavenging capacity of six compounds and Vc are were significant. Conclusion: Six pounds isolated from E. breviscapus have the stronger antioxidant activity.