Isolation and purification of polysaccharides from Mongolian medicine Narenmandula and its antioxidant activity

Objective: To study the isolation and qualitative analysis and antioxidant activity of polysaccharides from Mongolian medicine Narenmandula.Methods: Polysaccharides were extracted by water extraction and alcohol precipitation,then processed by deproteinization with Sevag method,decolorization with H2O2,and dialysis,then were further purified by through DEAE-Cellulose and SephdexG-100 column chromatography.The scavenging effect on oxygen free radicals and inhibition of lipid peroxidation(LPO) of polysaccharides were analyzed by the colorimetric method.Results: The content of crude polysaccharides was 61.9%,and the content of purified polysaccharides was 91.7% in Mongolian medicine Narenmandula,respectively.The scavenging effect of polysaccharides on.OH was weaker than that of benzoic acid,but stronger than that of Vc and mannitol,and polysaccharides had a weaker scavenging effect on.O2-than benzoic acid and Vc,but stronger than mannitol.When the polysaccharide concentration reached a certain level,it could effectively reduce the content of malondialdehyde(MDA),the final product of LPO.Conclusion: The polysaccharide of Mongolian medicine has a strong scavenging effect on.OH and.O2-,whose activity is positively correlated with concentration;and it can inhibit lipid peroxidation at certain degree.