Adewoye E O, Ige A O
Department of Physiology, College of Medicine, University of Ibadan, Ibadan.
Niger J Physiol Sci. 2013 Jun 30;28(1):91-7.
Diabetes mellitus is a metabolic disorder resulting from necrosis of β-cell and insulin resistance at the cellular level. Musa sapientum has been shown to possess anti-diabetic properties, however, the mechanism of its action is unknown. The effect of Methanolic extract of Musa sapientum leaves (MEMSL) and its fractions were assessed for in vitro inhibitory activity of α-amylase enzyme, in vivo hypoglycemic properties and liver glycogen content in alloxan-induced diabetic rats. Dried plant powder of Musa sapientum was successively extracted using n-hexane, ethyl acetate, dichloromethane and methanol respectively. The filtrate obtained was evaporated using rotary evaporator and the extract was stored at 4°C until use. The methanolic extract obtained was further fractionated using column chromatography. In vitro alpha amylase inhibitory activity of the methanolic extract at different doses (2.5mg/ml, 5mg/ml, 10mg/ml, 25mg/ml and 50mg/ml) and column fractions (100ug/ml) were assessed and compared with that of acarbose (5mg/ml), a standard oral α-amylase inhibitor. Hypoglycemic activity and liver glycogen content was studied using alloxan -induced diabetic male rats treated with MEMSL (250mg/kg and 500mg/kg), column fractions F2 and F5 (100μg/kg) for 14 days respectively. Results obtained showed a dose -dependent increase in α-amylase inhibitory activity of the methanolic extract at 5, 10, 25 and 50mg/ml exhibiting 29%, 61%, and 72% and 80% inhibitory activities respectively. Column fractions 2 and 5 showed the highest α-amylase inhibitory activity of 79% and 74% respectively. The MEMSL at 250mg/kg and 500mg/kg exhibited 66% and 59% hypoglycemic activities respectively compared with diabetic controls. Fractions 2 and 5 showed 48% and 75% reduction in blood glucose level respectively. Liver glycogen in diabetic animals treated with MEMSL (250mg/kg and 500mg/kg), F2 and F5 were significantly increased (5.5±0.5, 5.9±0.7, 3.6±0.5, 8.0±0.4 mg/100gwt. liver) compared with Diabetic controls (1.2±0.3 mg/100gwt. liver) respectively suggesting an increase in glucose storage or reduction in glycogen breakdown. It seems possible that the anti-diabetic properties in the leaf extract of Musa sapientum and its fractions maybe due to the inhibition of α-amylase, increased storage of glucose as glycogen in the liver and/or reduced breakdown of liver glycogen stores.
糖尿病是一种由β细胞坏死和细胞水平的胰岛素抵抗引起的代谢紊乱疾病。已表明芭蕉具有抗糖尿病特性，然而，其作用机制尚不清楚。评估了芭蕉叶甲醇提取物（MEMSL）及其馏分对四氧嘧啶诱导的糖尿病大鼠的体外α-淀粉酶抑制活性、体内降血糖特性和肝糖原含量。分别用正己烷、乙酸乙酯、二氯甲烷和甲醇依次提取芭蕉干燥植物粉末。所得滤液用旋转蒸发仪蒸发，提取物储存在4°C下备用。将得到的甲醇提取物进一步用柱色谱法分离。评估了不同剂量（2.5mg/ml、5mg/ml、10mg/ml、25mg/ml和50mg/ml）的甲醇提取物和柱馏分（100μg/ml）的体外α-淀粉酶抑制活性，并与标准口服α-淀粉酶抑制剂阿卡波糖（5mg/ml）进行比较。分别用MEMSL（250mg/kg和500mg/kg）、柱馏分F2和F5（100μg/kg）处理四氧嘧啶诱导的糖尿病雄性大鼠14天，研究其降血糖活性和肝糖原含量。所得结果显示，甲醇提取物在5、10、25和50mg/ml时的α-淀粉酶抑制活性呈剂量依赖性增加，分别表现出29%、61%、72%和80%的抑制活性。柱馏分2和5分别显示出最高的α-淀粉酶抑制活性，为79%和74%。与糖尿病对照组相比，250mg/kg和500mg/kg的MEMSL分别表现出66%和59%的降血糖活性。馏分2和5分别使血糖水平降低48%和75%。与糖尿病对照组（1.2±0.3mg/100gwt肝脏）相比，用MEMSL（250mg/kg和500mg/kg）、F2和F5处理的糖尿病动物的肝糖原显著增加（分别为5.5±0.5、5.9±0.7、3.6±0.5、8.0±0.4mg/100gwt肝脏），这表明葡萄糖储存增加或糖原分解减少。芭蕉叶提取物及其馏分的抗糖尿病特性可能是由于抑制α-淀粉酶、增加肝脏中糖原形式的葡萄糖储存和/或减少肝脏糖原储备的分解。
