滇越金线兰活性部位降血糖、增敏胰岛素和抗氧化活性研究

采用高糖高脂饮食联合低剂量STZ诱导造成糖尿病大鼠模型，实验组大鼠分别灌胃给予滇越金线兰总膏和溶剂萃取法所得各极性部位，测定给药后大鼠血糖、胰岛素敏感性、抗氧化活性及NO水平等相关指标。胰腺切片，进行病理学检查。与模型组相比，乙酸乙酯部位给药组的随机血糖可见明显降低，从给药前402．66至226．26mg／dl（P〈0．05），而且该组大鼠的体重值明显高于模型对照组，同时能提高胰岛素敏感性，改善高糖负荷以后的糖耐量；胰腺细胞形态较模型组有明显改善；同时SOD活性增加，NO含量均显著降低。表明滇越金线兰的乙酸乙酯部位是其降血糖的主要活性部位，其作用机制可能与改善胰岛素抵抗、增强机体抗氧化活性和降低血浆NO等机制有关。

Antihyperglycemic,insulin-sensitizing and antioxidant activities of the active fractions from Anoectochilus chapaensis

Anoectochilus chapaensis Gagnep. （Orchidaceae）, an indigenous and valuable Chinese folk medicine, has been widely used in China to treat diabetes. However, few reports are available about its constituents and activity. The present experiment was conducted to investigate the active fractions from A. chapaensis in diabetic rat model induced by high-fat diet plus streptozotocin. The total EtOH extract from the whole herbs ofA. chapaensis, half of which was partitioned in sequence with petrol ether （PE）, ethyl acetate （EtOAc）, n-BuOH and H2O, thus yielding four fractions, all of them were orally administered with an identical dose amount to 4 g/kg dried crude herbs once a day for consecutive two weeks to further investigate the antihyperglycemic activity. The EtOAc fraction caused a significant fall in the non-fasting blood glucose level of diabetic rats from （402.66±82.26） to （226.26±62.10） mg/dl, which may be attributed to ameliorating insulin resistance, modulating the activity of enzymatic antioxidants, reducing the content of NO, etc. Much more intact β cells in the islets of Langerhans in EtOAc fraction-treated groups than the negative control were observed, which greatly supported the morphological and functional elucidation. The OGTT evidenced that EtOAc fraction could promote the endurance capacity of acute glucose increase in diabetic rats. The EtOAc fraction of A. chapaensis contains some hypoglycemic and antioxidant principles with the potential to be developed further for the treatment of diabetes specifically associated with an insulin resistance state.