夏枯草酸性多糖的理化性质分析及其抗氧化活性

水提醇沉后的夏枯草粗多糖用HZ-820大孔吸附树脂脱色素和蛋白质,再经DEAE-Sepharose Fast Flow离子交换柱色谱和Sephadex G-50凝胶柱色谱进一步纯化得到高纯度酸性多糖,用气相色谱、高效凝胶渗透色谱、红外光谱、热稳定性分析、扫描电镜等对其理化性质进行了分析,最后研究了其抗氧化活性。结果表明,夏枯草酸性多糖中含有鼠李糖、木糖、阿拉伯糖、葡萄糖和甘露糖,其质量分数分别为0.985 7%、1.756 8%、3.202 9%、1.975 3%、0.680 6%,重均相对分子质量为57 234。夏枯草酸性多糖在230℃开始发生降解,600℃基本结束,说明其具有较好的热稳定性。夏枯草酸性多糖表面基本光滑,呈薄片状且无规则蜷曲。抗氧化研究表明,夏枯草酸性多糖能够有效地清除NO2-自由基,同时具有较强的还原能力和对铁离子的螯合能力。

Physical-Chemical Properties Analysis 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.