两种毛大丁草多糖 Gbp和 Gcp的组成研究

目的　从毛大丁草的根中分离提取多糖 ,测定其组成。方法　毛大丁草根的水提物经脱蛋白、脱色、乙醇沉淀得两种粗多糖 ,再经过 Sephadex G- 75和 Sephadex G- 5 0凝胶柱色谱纯化得到两种纯多糖 Gbp和 Gcp,用高效凝胶色谱 (HPGPC)测定 Gbp和 Gcp相对分子质量 ,通过完全酸水解后 ,进行三甲基硅醚化的 GC- MS分析 ,测定两种多糖的组成。结果　 Gbp和 Gcp重均相对分子质量分别为 6 .6 5× 10 5和 7.4 5× 10 4 。 Gbp是由木糖、来苏糖、鼠李糖、核糖、葡萄糖和半乳糖组成 ,其比例约为 3∶ 3∶ 3∶ 2∶ 6∶ 2 ;Gcp主要由果糖组成 ,还有少量葡萄糖和木糖 ,其比例为 2 4∶ 4∶ 1。结论　通过凝胶柱色谱分析 ,所提取两种多糖 Gbp和 Gcp均为单一、纯净的多糖

Study on composition of two polysaccharides Gbp and Gcp from root of Gerbera piloselloides

Object To study the composition of two polysaccharides Gbp and Gcp which were isolated and purified from Gerbera piloselloides (L.) Cass.Methods The polysaccharides were extracted with hot water and precipitated by alcohol. Protein in the precipitates was removed by Sevag method. The products were further purified with column chromatography on Sephadex-75 and Sephadex-50. The molecular weights of Gbp and Gcp were measured by HPGPC. Their compositions were studied by using GC-MS after acid hydrolysis and trimethylsilylation. Results The weight-average molecular weights of Gbp and Gcp are 6.65×10⁵ and 7.45×10⁴ respectively (with polyoxyethylene glycol as a reference). Gbp is consisted of lyxose, xylose, robitose, glucose, and galactose, the rate is 3:3:3:2:6:2. Gcp is composed of fructose, glucose, and xylose (24:4:1). Conclusion Gbp and Gcp are shown to be homogeneous by gel permeation chromatograhy.