绿茶提取物对糖尿病大鼠糖耐量的影响及机制研究

目的　研究绿茶提取物对糖尿病大鼠糖耐量的影响及其机制。方法　给糖尿病大鼠口服蔗糖或淀粉和绿茶提取物后 ,观察绿茶提取物对糖尿病大鼠糖耐量的影响 ,并用比色法测定绿茶提取物对α-葡萄糖苷酶 (EC 3.2 .1.2 0 )和α -淀粉酶 (EC 3.2 .1.1)的抑制活性。结果　绿茶提取物可明显改善蔗糖或淀粉负荷糖尿病大鼠的血糖水平。在糖尿病相关酶的抑制试验中 ,绿茶提取物显示有较强的α -葡萄糖苷酶抑制活性 ,其α -葡萄糖苷酶的半抑制浓度(IC50 )值为 0 .13g/L ;绿茶提取物对α-淀粉酶的抑制活性则较弱 ,浓度为 1g/L时 ,其对α -淀粉酶的抑制率为 2 1%。结论　绿茶提取物能够降低糖尿病大鼠糖负荷血糖 ,可能由其对α -葡萄糖苷酶和α -淀粉酶的抑制作用所致

Study of effect and its mechanism of green tea extract on glucose tolerance in diabetic rats

Objective It is to study the effect and its mechanism of green tea extract on glucose tolerance in diabetic rats.Methods The effect of green tea extract on glucose tolerance of diabetic rats was observed after the diabetic rats were took orally with sucrose or starch and green tea extract. Then the inhibitory activities of green tea extract on alpha-glucosidase (EC 3.2.1.20) and alpha-amylase (EC 3.2.1.1) were determined with colorimetric method.Results Green tea extracts significantly improved the blood sugar level of the diabetic rats loaded with sucrose or starch. In inhibitory test of diabetes correlative enzyme, green tea extract showed stronger inhibitory activity on alpha-glucosidase and its IC 50 value was 0.13 g/L. While the inhibitory activity of green tea extract on alpha-amylase was faintish and its inhibitory rate was 21% at the IC 50 value of 1 g/L.Conclusion Green tea extract can reduce the blood sugar level of the diabetic rats loaded with glucose, the mechanism maybe the inhibitory effects on alpha-glucosidase and alpha-amylase.