铁皮石斛多糖降血糖作用研究

目的 研究铁皮石斛中多糖种类及其降血糖功能。方法 采用DEAE-纤维素阴离子交换色谱分离铁皮石斛粗多糖，三甲基硅醚衍生化法测定分离多糖的单糖组成，红外光谱表征分离多糖的结构。采用四氧嘧啶诱发小鼠糖尿病模型研究分离多糖对模型小鼠空腹血糖值、血清胰岛素水平及糖化血清蛋白含量的影响。结果 铁皮石斛中分离得到4种分离多糖，含量最高分离多糖DOP1的单糖组成为阿拉伯糖、半乳糖、葡萄糖及甘露糖（摩尔比为3.5∶1.2∶1.5∶1.0）。红外光谱分析结果与单糖组成研究相符，同时显示4种分离多糖均为硫酸多糖。4种分离多糖在给药21d后能够显著降低糖尿病模型小鼠的空腹血糖值（P<0.01）、提高血清胰岛素水平（P<0.05~0.01）以及降低糖化血清蛋白含量（P<0.01），其中以DOP1作用最强。结论 铁皮石斛分离多糖具有显著的降血糖作用。 

The Hypoglycemic Activity of Homogeneous Polysaccharides from Dendrobium Officinale

OBJECTIVE To characterize the homogeneous polysaccharides from Dendrobium officinale Kimura et Migo and study the hypoglycemic activity of the isolated polysaccharides. METHODS DEAE-cellulose anion-exchange chromatography was used to isolate homogeneous polysaccharides from crude polysaccharides (DOP); Monosaccharide composition was analysed after trimethylsilation; and the chemical structure of isolated polysaccharide was characterized with infrared spectroscopy; The effects of isolated polysaccharides on the levels of fasting blood glucose， plasma insulin， and glycosylated serum protein were estimated using diabetic mice models induced by alloxan. RESULTS Four isolated polysaccharides were isolated from DOP， in which DOP1 had the highest content. DOP1 was composed of arabinose， galactose， glucose and mannose in a molar ratio of 3.5∶1.2∶1.5∶1.0. The infrared spectroscopy of various isolated polysaccharides showed that they all had the obvious characteristic absorption peaks of corresponding monosaccharides. The levels of fasting blood glucose and glycosylated serum protein decreased obviously after a 21 day ig administration in diabetic mice models（P<0.01）， in addition， all the four isolated polysaccharides increased glycosylated serum protein levels in varying degrees after a 21 day dosage (P<0.05~0.01). DOP1 displayed the optimal effects on the improvements of above three biochemistry indexes compared with the other three isolated polysaccharides. CONCLUSION Four isolated polysaccharides from DOP displayed hypoglycemic activity in diabetic mice models induced by alloxan.