Objective:To investigate the antioxidant effect in vitro of polysaccharides in Sophora alopecuroides (SAP) and its derivatives. Method: After sulfation and phosphorylation of the SAP

the scavenging capacities of 1

1-diphenyl-2-picrylhydrazyl

superoxide anion radicals

hydroxyl free radicals and reducing power were assayed

with vitamin C(VC) as control. Result: The activity of modification products was increased with the concentration increasing. The scavenging rate against 1

1-dipheny 1.2-picrylhydmiyl DPPH 50% inhibition concentration (IC50

4.573 mg·L-1) and superoxide anion radicals IC50 2.651 mg·L-1 of SAPS were more than SAP. The scavenging rate against DPPH IC50

6.542 mg·L-1 and hydroxyl free radicals IC50 4.368 mg·L-1 of SAPP were more than SAP. Conclusion: The antioxidant activity of polysaccharides in S. alopecuroides can be improved through sulfation and phosphorylation of the SAP.