Moringa oleifera leaf extract lowers high blood pressure by alleviating vascular dysfunction and decreasing oxidative stress in L-NAME hypertensive rats.
BACKGROUND
Enhancing relaxation of resistance arteries and decreasing oxidative stress by using natural products are potential strategies for prevention and treatment of hypertension.


PURPOSE
This study investigated whether aqueous extract of Moringa oleifera leaves (MOE) could alleviate Nω-nitro-L-arginine-methyl ester (L-NAME)-induced high blood pressure via modulation of vascular function and antioxidant properties.


METHODS
An experimental hypertensive model was established by administration of L-NAME (50 mg/kg/day) in drinking water to male Wistar rats for 3 weeks. Arterial pressure was measured indirectly by tail-cuff plethysmography and directly via femoral artery catheterization. Vasoreactivity of isolated rat mesenteric arterial bed was determined by the changes in perfusion pressure detected by a pressure transducer. Vascular superoxide anion (O2•-) production was determined by lucigenin-enhanced chemiluminescence. Other biochemical measurements including malondialdehyde (MDA) level, superoxide dismutase (SOD), and catalase (CAT) activities were measured by colorimetric assay.


RESULTS
L-NAME-treated rats developed significantly increased blood pressure and heart rate. Concurrent oral treatment with MOE (30 and 60 mg/kg/day) could decrease the high blood pressure and tachycardia in a dose-dependent manner. MOE reduced the impairment of acetylcholine-induced relaxation and decreased the hyperreactivity of adrenergic-mediated contraction in response to periarterial nerve stimulation and phenylephrine in isolated mesenteric arterial beds. In addition, MOE exhibited antioxidant effects in the hypertensive rats, as indicated by suppression of vascular O2•- production, decrease of plasma and thoracic aorta MDA levels, and increase of antioxidant activities of SOD and CAT. Moreover, MOE (0.001-0.3 mg) produced a dose-dependent relaxation in methoxamine pre-contracted arterial beds isolated from L-NAME hypertensive rats, which was abolished by endothelium denudation.


CONCLUSION
These findings suggest that the antihypertensive effect of MOE in L-NAME-hypertensive rats may be mediated by alleviating vascular dysfunction and oxidative stress and promoting endothelium-dependent vasorelaxation. MOE may be potentially useful as a natural product against hypertension.
['Aekthammarat|Direk|D|', 'Pannangpetch|Patchareewan|P|', 'Tangsucharit|Panot|P|']
D000109:Acetylcholine D000818:Animals D000959:Antihypertensive Agents D002374:Catalase D004305:Dose-Response Relationship, Drug D006339:Heart Rate D006973:Hypertension D008297:Male D008315:Malondialdehyde D008638:Mesenteric Arteries D029588:Moringa oleifera D019331:NG-Nitroarginine Methyl Ester D018384:Oxidative Stress D010936:Plant Extracts D017208:Rats, Wistar D013482:Superoxide Dismutase D014664:Vasodilation
Moringa oleifera Vascular dysfunction Oxidative stress L-NAME Mesenteric artery Antihypertensive effect