茶花提取物对实验性糖负荷小鼠糖吸收的抑制作用

目的：研究茶花提取物对实验性糖负荷小鼠糖吸收的抑制作用。方法雄性昆明种小鼠分为糖负荷模型组、阿卡波糖（6.25 mg/kg）对照组、茶花提取物150及300 mg/kg剂量组，每组8只小鼠。模型组分别以葡萄糖（2 g/kg）、蔗糖（4 g/kg）和淀粉（6 g/kg）灌胃建立3种糖负荷餐后高血糖模型，给药组小鼠糖负荷前1 d及30 min分别灌胃给予阿卡波糖或茶花提取物，检测糖负荷后不同时间小鼠的血糖水平，探讨茶花提取物对小鼠糖吸收的影响。采用酶标法检测茶花提取物对体外和小鼠小肠黏膜α-葡萄糖苷酶的抑制活性。结果茶花提取物（150和300 mg/kg）及阿卡波糖（6.25 mg/kg）对葡萄糖负荷小鼠血糖水平的影响无显著性差异，但能明显降低蔗糖负荷20 min时的小鼠血糖水平（P＜0.05），能明显降低淀粉负荷20 min和40 min时小鼠血糖水平（P＜0.05）。茶花提取物150和300 mg/kg对小鼠小肠黏膜α-葡糖苷酶活性的抑制率分别为18.8%和31.1%，茶花提取物对α-葡糖苷酶的体外抑制活性（IC50值）为1.50 mg/ml。结论茶花提取物能有效降低糖负荷后的血糖水平，其作用机制可能与抑制α-葡萄糖苷酶活性有关。

Inhibition effects of tea flower extract on glucose absorption in experimental glucose tolerance mice

Objective To study the inhibitory effects of tea flower extract（TFE） onα-glucosidase and glucose intestinal absor-ption. Methods Three different postprandial hyperglycemia models （2 g/kg glucose, 4 g/kg sucrose, and 6 g/kg starch） were used, with 8 mice in each group. Oral administration of 150 or 300 mg/kg of TFE, 6.25 mg/kg of acarbose, or water was performed on mice 1 day and 30 mins before the oral administration of 2 g/kg glucose, 4 g/kg sucrose, and 6 g/kg starch at 10 ml/kg of body weight. Blood glucose levels were analyzed chronologically to evaluate the effect of TFE. In vitro studies were also performed to study the inhibitory effects of TFE on α-glucosidase and small intestinal mucosa glycosidase. Results Neither TFE nor acarbose had significant influence in glucose-treated mice. However, there was a significant decrease in the postprandial blood glucose 20 min after sucrose administration （P〈0.05）, and 20 min and 40 min after starch administration （P〈0.05）. TFE also significantly inhibited the activities ofα-glucosidase of small intestinal mucosa, with 18.8%and 31.1%by 150 and 300 mg/kg TFE. The in vitro IC50 of TFE onα-glucosidase was 1.50 mg/ml. Conclusion TFE could effectively reduce the blood glucose level in hyperglycemic mice. Its mechanism might be related to the inhibitory effects ofα-glucosidase.