茶多糖对α-淀粉酶活性抑制作用及对糖尿病模型大鼠血糖影响研究

Effects of Cha Polysaccharides(CP) on α-amylase Suppression and Blood Glucose in Diabetic Rats

目的探索茶多糖的降血糖作用及其机制。方法采用水提醇沉法提取茶多糖,用3,5-二硝基水杨酸(DNS)比色法观察茶多糖在体外对α-淀粉酶活性的抑制作用及其对正常大鼠和四氧嘧啶所致糖尿病大鼠模型血糖的影响。结果体外实验显示,茶多糖对α-淀粉酶活性的抑制作用相当于阳性对照药阿卡波糖抑制作用(抑制率70.9%)的50%;动物实验显示,治疗组大鼠空腹血糖水平明显低于糖尿病模型组,差异有极显著性(P<0.01),给予茶多糖大鼠的餐后2 h血糖明显低于糖尿病模型组,差异有显著性(P<0.05);给予茶多糖大鼠的血糖水平与糖尿病模型组相比均显著降低(P<0.01)。结论茶多糖可降低四氧嘧啶所致糖尿病大鼠的空腹血糖及餐后血糖,其降血糖机制可能与其抑制α-淀粉酶活性,从而延缓碳水化合物在小肠的吸收有关。

Objective To study the inhibition effects of Cha polysaccharides （CP） on blood glucose and mechanisms underlying. Methods The CP was isolated by water extraction and alcohol precipitation. The in vitro inhibition of CP on α-amylase activity was assayed by using DNS （3,5-dinitro-salicylate）） method, and hypoglycaemic effects on normal rats and diabetes mellitus （DM） induced by alloxan were determined. Results In vitro studies showed that the suppression on α-amylase activity by CP （ suppression rate was 70.9% ） was equivalently to 50% of that by acarbose. In rat models, the fasting blood glucose in the CP treated group was remarkably lower than that in the model control group （ P 〈 0.01 ） ; the concentration of 2 h postprandial blood glucose in the CP treated group was significantly lower than that in the model control group（ P 〈 0.05 ）. Conclusion CP could decrease both fasting and postprandial blood glucose in alloxan elicited DM rats, and the potential methanism may be related to inhibiting the α-amylase activity and delaying the intestinal absorption of carbohydrates.