黄芩苷对小肠二糖酶的抑制作用

目的：研究黄芩苷对糖尿病大鼠的降血糖作用及其对大鼠小肠二糖酶的影响。方法：用大鼠小肠刷状缘膜匀浆分析黄芩苷对二糖酶活性的抑制作用；测定黄芩苷对正常小鼠蔗糖负荷糖耐量的影响；观察腹腔注射65mg．kg^-1链脲佐菌素（Streptozotocin，STZ）诱导的糖尿病大鼠用黄芩苷100和200mg.kg^-1治疗4周后，蔗糖负荷糖耐量，实验结束后，分析十二指肠、空肠和回肠黏膜中蔗糖酶的活力。结果：黄芩苷对蔗糖酶活性有抑制作用，对麦芽糖酶活性无抑制作用：正常小鼠灌胃给予黄芩苷后，显著降低蔗糖引起的血糖水平升高。糖尿病大鼠灌胃给予黄芩苷周后，黄芩苷显著降低糖尿病大鼠的血糖水平，减缓糖尿病大鼠体重降低的趋势，同时黄芩苷显著降低糖尿病导致的蔗糖酶活力增强。结论：黄芩苷降低血糖的机制之一可能是抑制小肠蔗糖酶的活性。

Inhibitory Effect of Baicalin on Disaccharidase in Small Intestine

Objective： The purpose of this study was to investigate the effect of baicalin （BA） on disaccharidase activities and explore the hypoglycemic mechanism of BA. Method： Brush border membrane from small intestine of rats was prepared. The membrane was incubated with different concentrations of BA. Sucrase and maltase activities were measured. Postprandial blood glucose testing of normal mice by sucrose-loading was investigated. Streptozotocin-induced diabetic rats were treated with 100 and 200 mg.kg-1 of BA twice daily for four weeks. Both age-matched normal control rats and diabetic rats only received 0.5% carboxymethyl cellulose sodium salt （CMC-Na） aqueous solution. The plasma glucose level and body weight were monitored every week. At the end of treatment, the disaccharidase activities in small intestine were measured. Results： In vitro, BA may significantly inhibit sucrase activity in a dose-dependent manner, but not affect maltase activity. Sucrose-loading test in mice showed the blood reduction with BA was slightly less than that with acarbose, but more effective than that with vehicle. Four-week treatment of BA may significantly decrease blood glucose levels, increase body weight and reverse increase of sucrase activity in small intestine of diabetic rats. Conclusion： Baicalin shows its anti-diabetic effect partly via inhibiting small intestine disaccharidases.