Objective: To assess the antioxidant activities of polysaccharide from Acalypha australis L. by different ethanol concentration in vitro. Method: The different part of polysaccharide were precipitated by 30%

45%

60%

75%

80% ethanol. The scavenging rate of the precipitated polysaccharides on (DPPH·)free radical

superoxide anion radical(O2-·)

hydroxyl radicals(·OH) was investigated by ferric reducing method

DPPH·radical assay

O2-·radical assay and thiobarbituric acid method respectively. The total antioxidantive capacity (T-AOC) and the inhibition on lipid peroxide (LPO) of the precipitated polysaccharides were also been determined. Result: The scavenging activities on the DPPH·reached 73.85%. The results showed that T-AOC was enhanced with the increase of polysaccharide concentration. The antioxidantive especially the scavenging activities on the O2-·and·OH reached 92.47%

95.89% respectively at 5 g·L-1.Furthermore the scavenging effects were as much as that of vitamin C(VC). The inhibition of LPO with the polysaccharide precipitated by 75% ethanol was significantly higher than that of any by other ethanol concentrations. Conclusion: the precipitated polysaccharides from A. australis showed strong antioxidant activities.