一种四环吲哚衍生物降血糖和降血脂活性评价与作用机制

Anti-hyperglycemic and Anti-hyperlipemic Activity Evaluation andMechanism of Action of a Tetracyclic Oxindole Derivative

四环吲哚衍生物7i是前期研究发现的高活性α–葡萄糖苷酶抑制剂,但其作用机制以及体内降血糖和降血脂活性尚不明确.本研究通过体外酶水平的透析实验和荧光探针分析等手段揭示了化合物7i以不可逆的方式与α–葡萄糖苷酶结合并抑制其活性.通过3T3-L1和HepG2细胞模型分析发现,化合物7i显著提高磷酸腺苷活化蛋白激酶(AMPK)和乙酰辅酶A羧化酶(ACC)蛋白磷酸化水平,降低脂质积累.另外,利用糖尿病小鼠模型研究发现,化合物7i能够有效抑制糖尿病小鼠的餐后血糖水平,改善葡萄糖耐量,降低血清中甘油三酯和胆固醇的含量,并且能够改善糖尿病小鼠肝脏的水肿和脂肪变性.因此,化合物7i通过抑制α–葡萄糖苷酶和调节AMPK/ACC磷酸化水平的双重作用机制起到降低血糖和血脂的作用,为其开发成为新型抗糖尿病药物奠定了基础.

Our previous research revealed that tetracyclic oxindole 7i was a potentα-glucosidase inhibitor.However,the mechanism of a tetracyclic oxindole 7i on hyperglycemia and hyperlipidemia in vivo and in vitro were unclear.In this study,the kinetic,intrinsic fluorescence and hydrophobic analyses ofα-glucosidase on 7i showed that 7i,as anα-glucosidase inhibitor,directly bound toα-glucosidase and inhibited enzyme in an irreversible manner.Moreover,the effect on lipid accumulation and Western blot in HepG2 and 3T3-L1 cells was analyzed.The results exhibited that 7i apparently reduced blood lipid content and increased the phosphorylation level of AMPK and ACC.In addition,the type 2 diabetic mice were treated with compound 7i.The results demonstrated that increase levels of postprandial blood glucose and total cholesterol and triglycerides of diabetic mice were significantly suppressed in the 7i-administered group in vivo.The histological observations showed that 7i improved hydropic degeneration and steatosis of diabetic mouse liver.These results provide new insights into the molecular mechanisms of 7i alleviated hyperglycemia and hyperlipemia by inhibitingα-glucosidase and regulating the AMPK/ACC pathway,and indicate that 7i may be a promising therapeutic agent for the treatment of diabetes.