莲子多糖的结构分析及抗氧化活性

用热水浸提、乙醇沉淀、Sevag法除蛋白分离得到水溶性莲子粗多糖。经十六烷基三甲基溴化铵（CTAB）沉淀，硼酸反应以及SephadexG-150层析纯化，得到3种莲子多糖SN1、SN2、SN3。用气相色谱、红外光谱、紫外光谱分析其化学结构。结果表明：SN1主要由葡萄糖、半乳糖组成，含a—D-吡喃葡萄糖环；SN2主链为葡聚糖、并含有其他4种单糖；SN3含7种单糖，并推测是一种酸性氨基多糖或蛋白多糖。体外抗氧化活性实验表明莲子多糖具有一定的清除自由基能力，清除·O2-的能力较强。

Semen Nelumbinis polysaccharide structure and antioxidant activity

A water soluble polysaccharide from Semen Nelumbinis was obtained by hot water extraction, and precipitated by ethanol. Three polysaccharide fractions （SN1 ,SN2, SN3） were separated from crude polysaccharide using cetyhrimethyl ammonium bromide （ CTAB ） precipitation, boric acid complex, and Sephadex G-150 column. Their chemical compositions were determined by gas chromatography, infrared spectroscopy, and ultraviolet spectroscopy. The results show that SN1 mainly composed of glucose, and galactose, including a-D-glucopyranosyl ring; SN2 had glucan as main chain, including 4 other mono- saccharides; SN3 had 7 monosaccharides, thus suggesting that amino acid was a polysaccharide or pro- teoglycan. On the basis of hydroxyl radical assay （·OH）, superoxide radical assay （· O2- ）, the antioxidant activities of crude polysaccharide were investigated. Among these contents,polysacchride had higher scavenging ability on superoxide anion-scavenging activities.