An Analysis of the Physicochemical Properties and Antioxidant Activity of Acidic Polysaccharide from Prunella vulgaris Linn

Crude polysaccharides obtained from Prunella vulgaris Linn by boiling water extraction and ethanol deposition were decolorized and deproteinized with HZ-820-type resin adsorptive and further purified by DEAE-Sepharose Fast Flow ion-exchange column chromatography and Sephadex G-50 Gel column chromatography.The physicochemical properties of the purified acidic polysaccharide were analyzed by gas chromatography,high-performance gel permeation chromatography,infrared,thermal analysis and scanning electron microscopy.Its antioxidant activity was also studied.The results indicated that the acidic polysaccharide was composed of rhamnose,xylose,arabinose,glucose and mannose,and their relative content was 0.985 7%,1.756 8%,3.202 9%,1.975 3% and 0.680 6%,respectively.The weight-average molecular weight of the acidic polysaccharide was 57 234.The acidic polysaccharide began to degrade at 230 ℃ and the degradation ended at 600 ℃,showing its better thermal stability,with smooth surface and in the shape of random coils and thin slices.The studies on its antioxidant activity show that the acidic polysaccharide obtained from Prunella vulgaris Linn had eliminating capability on NO-2 radical,and also had significant reducing power and chelating ability on ferrous ions.