当归多糖的分离纯化及其部分理化性质的研究

Isolation, purification and partial properties of polysaccharides from Angelica sinensis

目的 对甘肃岷县产当归中获得的当归多糖 (ASP)进行分离纯化 ,并测定其部分理化参数。方法 采用水煮 -醇沉法从新鲜当归中提取当归粗多糖 ,Sevag法除蛋白 ,冷冻干燥。苯酚 -硫酸法测定总糖含量 ;UV法及IR法检测多糖性质 ;自动旋光仪测定旋光度 ;采用凝胶渗透色谱 -激光光散射联用技术 (SEC -LLS)分析多糖的分子量范围及其分布 ;HPLC鉴定多糖的单糖组分及其相对百分比含量。结果 所得当归多糖为浅米灰色 ,无甜味 ,易溶于水 ,总糖含量为 96 .8% ;192nm处有明显吸收峰 ,2 6 0、2 80nm处均无吸收峰 ,证明被测物为多糖 ,且不含核酸及蛋白质 ;红外吸收光谱分析 ,在 335 2、2 94 0、174 7、16 2 6、14 14、12 37、10 2 1、5 36cm-1处表现为典型的多糖吸收峰 ;旋光度为 +94 .6° ,糖残基间的苷键可能为α -糖苷键 ;分子量在 1× 10 4～1 1× 10 5之间 ,80 %的组分集中在 4 3× 10 4左右 ;当归多糖主要由葡萄糖、阿拉伯糖、半乳糖、鼠李糖和木糖组成 ,其摩尔比值为 17.8∶5 .8∶12∶1∶2 .2。结论 所用方法提纯的当归多糖糖含量较高。

OBJECTIVE To isolate and purify the polysaccharides fractions from Angelica sinensis(ASP), and to determine the partial characters. METHODS Hot water extracting and ethanol precipitating method were employed to isolate polysaccharides from fresh Angelica sinensis. After the removal of protein by Sevag method, the purified ASP was dried by frozen drier. The amount of total carbohydrates of ASP was measured with phenol-sulfuric acid method. FT-IR spectrometry, UV-spectrophotometer, and automatic spectropolarimeter were used to determine the characteristic absorption and optical rotation of the polysaccharides, respectively. Size exclusion chromatography with laser light scattering (SEC-LLS) technology was employed to measure the molecular masses . The monosaccharides contained in ASP were analysed by HPLC. RESULTS The amount of total carbohydrates in ASP was 96.8%. Both UV and IR displayed representative polysaccharides properties. The molecular weight distribution was 1×10 4-1.1×10 5, and eight percent was distributed in 4.3×10 4. The monosaccharides constituent of ASP were glucose, arabinose, galactose, rhamnose and xylose, and their molar proportions were 17.8∶5.8∶12∶1∶2.2. CONCLUSION The amount of total carbohydrates is high in ASP distilled by this method. The range of molecular weight and monosaccharides constituents of ASP are affirmed.