Hypoglycaemic and hypotensive effects of Momordica charantia Linn (Cucurbitaceae) whole-plant aqueous extract in rats : cardiovascular topics

Various morphological parts (roots, stems, leaves and fruits) of Momordica charantia Linn (family: Cucurbitaceae) are used traditionally in African folk medicine to manage, control and / or treat a plethora of human ailments, including diabetes mellitus and hypertension. In order to scientifically appraise some of the folkloric, anecdotal and ethnomedical uses of M charantia, the present study was undertaken to investigate the hypoglycaemic and hypotensive effects of M charantia whole-plant aqueous extract (MCE) in rat experimental paradigms. The hypoglycaemic effect of the plant extract was examined in normal and diabetic rats, using streptozotocin (STZ)- induced diabetes mellitus models. Normotensive (normal), and hypertensive Dahl salt-sensitive rats were used to probe the hypotensive (antihypertensive) effect of the plant extract. Chlorpropamide was used as reference hypoglycaemic agent for comparison. Acute oral administrations of the plant extract caused dose-related, significant hypoglycaemia in normal (normoglycaemic) and STZ-treated, diabetic rats. Furthermore, acute intravenous administrations of MCE produced dose-dependent, significant reductions in systemic arterial blood pressure and heart rates of normal, and hypertensive Dahl salt-sensitive rats. Although the exact hypoglycaemic and hypotensive mechanisms of action of the plant extract remain speculative at the moment, it is unlikely that the herb causes hypotension in the mammalian experimental animal model used via cholinergic mechanisms, since its cardiovascular effects are resistant to atropine pretreatment. However, the findings of this experimental animal study indicate that the plant extract possesses hypoglycaemic and hypotensive properties, and therefore, lend pharmacological credence to folkloric, ethnomedical uses of the plant in the management and / or control of diabetes mellitus and hypertension in some rural African communities.