山荆子叶总黄酮对糖尿病小鼠血糖、血脂的作用

目的：研究山荆子叶总黄酮（Malus baccata leaf total flavonoids，MLTF）对链脲佐菌素（streptozotocin，STZ）致糖尿病小鼠的降糖、降脂作用。方法：用体积分数为70%的乙醇提取山荆子叶中总黄酮，并用高效液相色谱法测定其有效成分含量；采用STZ（100 mg/kg）腹腔注射诱导形成糖尿病小鼠模型。实验小鼠分正常对照组、模型组、阳性对照组（盐酸二甲双胍，250 mg/kg）、MLTF高剂量组（500 mg/kg）、MLTF低剂量组（300 mg/kg）。MLTF灌胃4 周，每天测量体质量、饮食、饮水，并测量3 次空腹血糖值，最后测量小鼠口服葡萄糖耐受量。实验结束时处死小鼠，取肝脏、脾脏、肾脏和胸腺称质量计算脏器指数，收集血液，离心，血清用于测定血脂。结果：MLTF中含有芦丁（9.72 mg/g）、根皮苷（51.04 mg/g）、槲皮素（9.44 mg/g ）、根皮素（2.73 mg/g）；MLTF高剂量能显著降低小鼠空腹血糖值和提高口服葡萄糖耐受量药时曲线下面积（P＜0.05），低剂量在一定程度上能降低血糖；高、低剂量均能显著降低小鼠血清中甘油三酯、总胆固醇水平，改善高密度脂蛋白胆固醇水平；MLTF高、低剂量也可以很好地修复小鼠脏器受到的损伤。结论：MLTF可以明显改善糖尿病小鼠血糖和血脂的紊乱。

Effect of Total Flavonoids from Malus baccata Leaves on Blood Glucose and Blood Lipid in Diabetic Mice

Objective: To study the hypolipidemic and hypoglycemic effects of total flavonoids from Malus baccata leaves (MLTF)
on STZ-induced diabetic mice. Methods: MLTF were extracted from Malus baccata leaves with 70% ethanol and its bioactive
components were quantified by HPLC. Diabetes mellitus was induced in mice by intraperitioneal injection of streptozotocin (STZ,
100 mg/kg). All mice were divided randomly into five groups, including normal control, diabetic model, metformin (250 mg/kg),
MLTF high-dose (500 mg/kg) and low-dose (300 mg/kg) groups. All mice were subjected to intragastic administration for 4
weeks. Body weight, and food and water intakes were monitored every day during the administration period, and fasting blood
glucose (FBG) was measured 3 times. We also tested the effect of MLTF on diabetic mice by using oral glucose tolerance test
(OGTT). At the end of the experiment, liver, kidney, spleen and thymus samples were removed and weighed to calculate the
tissue indexes. Blood samples were collected to evaluate blood lipid. Results: The contents of rutin, phlorizin, quercetin and
phloretin were 9.72, 51.04, 9.44 and 2.73 mg/g, respectively in MLTF. High-dose administration of MLTF could significantly
reduce the FBG and the area under the glucose tolerance curve (AUC). In contrast, low-dose MLTF could only improve the FBG
to some extent. Compared with the model group, both high-dose and low-dose MLTF could significantly decrease TG and TC
levels, and ameliorate HDL-C level. Our present study found that injured mouse organs could be repaired by low- and high-dose
administration of MLTF. Conclusion: MLTF can improve glucose and lipid abnormalities.