Effects of different extraction methods on antioxidant activity of Inonotus obliquus polysaccharides.

[Objective] This study aimed to explore the effects of different extraction methods on antioxidant activities of I.obliquus polysaccharides.[Method] Crude polysaccharides were extracted by using boiling ethanol precipitation method and ethanol-alkali extraction method;water-soluble and alkali-soluble polysaccharides were purified by using trichloroacetic acid method;antioxidant activities of I.obliquus polysaccharides were compared by hydroxyl radical scavenging experiment and superoxide anion radical scavenging experiment.[Result] Yield of crude water-soluble polysaccharides,crude alkali-soluble polysaccharides,pure water-soluble polysaccharides and pure alkali-soluble polysaccharides were 14.0%,27.7%,7.0% and 6.2%,respectively.Hydroxyl radical scavenging effect of crude water-soluble polysaccharides and pure alkali-soluble polysaccharides had achieved the maximum with polysaccharide concentration of 0.9 mg/ml and 0.06 mg/ml,and the scavenging rates were 54.3% and 10.9%,respectively;superoxide anion radical scavenging effect of crude water-soluble polysaccharides and pure water-soluble polysaccharides had achieved the maximum with polysaccharide concentration of 0.1 mg/ml and 0.07 mg/ml,and the scavenging rates were 24.2% and 27.2%,respectively.[Conclusion] Antioxidant activity of water-soluble polysaccharides was higher than that of alkali-soluble polysaccharides.I.obliquus could be used as a species of new efficient natural antioxidant medicinal fungi in application.