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Please use this identifier to cite or link to this item: http://hdl.handle.net/123456789/909

Authors: Mekoya, Mengistu
Advisors: Professor Yekoye Abebe
Keywords: Hypertention; Moringa stenopetala; Aqueous extract; in vitro; in vivo; Blood pressure; Acute toxicity; Phytochemical Screening
Copyright: 2007
Date Added: 23-Apr-2008
Publisher: Addis Ababa University
Abstract: Abstract Hypertension is sustained elevation of arterial blood pressure. It is the major cardiovascular risk factor contributing to myocardial infarction, cerbrovascular accidents, congestive heart failure, peripheral vascular insufficiency and premature mortality. Different medicinal plants have been used to treat hypertension. One such plant is Moringa stenopetala, a tree whose leaves, flowers, and fruits are used as vegetable in some areas of Southern Ethiopia. Different parts of M. stenopetala are also used to cure various diseases including hypertension. In this study, the in vivo and in vitro hypotensive properties of aqueous leaf extracts of Moringa stenopetala have been assessed on selected animal model. The crude aqueous leaf extract of M. stenopetala caused significant fall in systolic blood pressure (SBP), diastolic blood pressure (DBP) and mean arterial blood pressure (MABP) at the doses of 10, 20, 30 and 40 mg/kg in normotensive anaesthetized guinea pigs (n = 12). The percent fall in SBP was 25.42 ± 4.3% (p = 0.00), 33.3 ± 3.9% (p = 0.00), 41.27 ± 3.7% (p = 0.00), and 51.73 ± 3.9% (p = 0.00) at the respective doses of 10, 20, 30 and 40 mg/kg. At the same dose the percent fall in DBP was 27.76 ± 3.1% (p = 0.00), 38.38 ± 3.7% (p = 0.00), 52.51 ± 4.1% (p = 0.00) and 59.91 ± 3.7% (p = 0.00). The percent fall in MABP was also 26.74 ± 3.6% (p = 0.00), 36.2 ± 3.5% (p = 0.00), 47.62 ± 3.6% (p = 0.00) and 56.39 ± 3.5 % (p = 0.00) at the above respective doses. However, significant percent fall in pulse pressure was observed only at the cumulative dose of 40 mg/kg and the fall was 33.86 ± 8.9% (p = 0.01). The hypotensive effect might have been mediated by non-autonomic nervous system as its effect is not altered by atropine, which is muscarinic receptor blocker of acetylcholine, and propranolol, which is non-selective blocker of b-adrnergic receptors. The in vitro hypothensive study of M. stenopetala was carried out on isolated guinea pig aorta. High-K+ (80mM) induced sustained contraction of the aortic tissue preparation. However, the aqueous leaf extract of M. stenopetala caused dose and time dependent inhibition (vasodilation) of the induced contraction. The significant inhibition of high K+-induced contraction was 36.55 ± 8.64% (p = 0.001), 67.76 ± 9.55% (p = 0.00), and 95.56 ± 3.14% (p = 0.00) at respective doses of 5, 6 and 7 mg/ml (n = 10 and data are expressed as M ± SEM). Thus, the in vivo and in vitro studies justify traditional use of the leaves of M. stenopetala as antihypertensive agent by some localities of Southern Nations Nationalities and Peoples, Ethiopia. Furthermore, acute toxicity study of M. stenopetala showed that the extract was tolerable in mice when tested up to the oral dose of 10 g/kg with no mortality and behavioral changes. This also signifies that the leaves of the plant can be a safe source of food.
Description: A Thesis Submitted to the School of Graduate Studies of Addis Ababa University in Partial Fulfillment of the Requirements for the Degree of Master of Science in Medical Physiology
URI: http://hdl.handle.net/123456789/909
Appears in:Thesis - Medical Physiology

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