Gondwe M, Kamadyaapa D R, Tufts M, Chuturgoon A A, Musabayane C T
Department of Human Physiology, School of Medical Sciences, Faculty of Health Sciences, University of KwaZulu-Natal, Private Bag X54001, Durban 4000, South Africa.
Phytomedicine. 2008 Sep;15(9):699-709. doi: 10.1016/j.phymed.2008.02.004. Epub 2008 Apr 11.
Studies in our laboratories suggest that Sclerocarya birrea stem-bark ethanolic extract (SBE) has hypoglycemic properties. Accordingly, we investigated the effects of SBE on major complications of diabetes mellitus; blood glucose, renal function and mean arterial blood pressure (MAP) in non-diabetic and STZ-induced diabetic rats. Oral glucose tolerance test responses to various SBE doses (60, 120 and 240 mg kg(-1)) were studied in fasted rats following glucose load (0.86 g kg(-1), p.o.). Rats treated with deionized water (3 ml kg(-1) p.o.), or standard hypoglycemic drugs (insulin, 100 microg kg(-1), s.c.; metformin, 500 mg kg(-1), p.o. or glibenclamide, 500 microg kg(-1), p.o) acted as untreated and treated positive controls, respectively. Blood was collected in non-diabetic rats after 45 min of SBE, metformin or glibenclamide for plasma insulin determination. Acute SBE effects on renal function and MAP were studied in anesthetized rats challenged with hypotonic saline after 3.5h equilibration for 4h of 1h control, 1.5h treatment and 1.5h recovery periods. SBE was added to the infusate during the treatment period. Chronic effects were monitored for 5 weeks in animals daily treated with SBE (120 mg kg(-1) p.o.) while hepatic glycogen concentration was measured at the end of the experimental period. SBE exhibited dose-dependent reduction in blood glucose concentration. SBE and metformin did not affect plasma insulin secretion in non-diabetic rats, while glibenclamide increased plasma insulin concentration. The hypoglycemic effect of SBE treatment was associated with increased hepatic glycogen synthesis. Acute SBE administration did not significantly alter kidney function, but chronic SBE treatment for decreased plasma urea and creatinine concentrations of STZ-diabetic rats with concomitant increase in GFR by comparison with control rats at the corresponding period (0.7+/-0.2 vs. 1.4+/-0.3 ml min(-1)). SBE treatment reduced blood pressure in all groups of animals. The observations suggest that SBE has reno- and cardio-protective effects in diabetes mellitus. The current results indicate the basis for SBE use as complementary remedy in diabetes.
我们实验室的研究表明，可乐果茎皮乙醇提取物（SBE）具有降血糖特性。因此，我们研究了SBE对糖尿病主要并发症的影响；在非糖尿病和链脲佐菌素诱导的糖尿病大鼠中，观察其对血糖、肾功能和平均动脉血压（MAP）的影响。在禁食大鼠经口给予葡萄糖负荷（0.86 g kg(-1)）后，研究不同剂量SBE（60、120和240 mg kg(-1)）的口服葡萄糖耐量试验反应。分别用去离子水（3 ml kg(-1)，经口）、标准降糖药物（胰岛素，100 μg kg(-1)，皮下注射；二甲双胍，500 mg kg(-1)，经口；或格列本脲，500 μg kg(-1)，经口）处理的大鼠作为未处理和处理的阳性对照。在给予SBE、二甲双胍或格列本脲45分钟后，采集非糖尿病大鼠的血液用于测定血浆胰岛素。在麻醉大鼠中，在1小时对照、1.5小时处理和1.5小时恢复期平衡3.5小时后，用低渗盐水刺激，研究SBE对肾功能和MAP的急性影响。在处理期将SBE添加到输注液中。对每日用SBE（120 mg kg(-1)，经口）处理动物5周的慢性影响进行监测，同时在实验期结束时测量肝糖原浓度。SBE呈现出血糖浓度的剂量依赖性降低。SBE和二甲双胍对非糖尿病大鼠的血浆胰岛素分泌没有影响，而格列本脲增加了血浆胰岛素浓度。SBE治疗的降血糖作用与肝糖原合成增加有关。急性给予SBE没有显著改变肾功能，但与同期对照大鼠相比，SBE慢性治疗可降低链脲佐菌素诱导的糖尿病大鼠的血浆尿素和肌酐浓度，同时肾小球滤过率增加（0.7±0.2对1.4±0.3 ml min(-1)）。SBE治疗降低了所有动物组的血压。这些观察结果表明，SBE在糖尿病中具有肾脏和心脏保护作用。当前结果表明了SBE用作糖尿病辅助治疗药物的依据。
