Hydrogen sulfide as a mediator of endothelium-dependent relaxation evoked by Moringa oleifera leaf extract in mesenteric arterial beds isolated from L-NAME hypertensive rats

Moringa oleifera and Blood Pressure: Evidence and Potential Mechanisms

The prevalence of hypertension is increasing worldwide, in particular in developing countries. Anti-hypertensive drugs are commonly used to treat hypertension. However, in developing countries, where access to health care is scarce and the supply system is poor, anti-hypertensive drugs may not always be available. Moringa oleifera is a plant widely found in developing countries, with its leaves, seeds, flowers, roots, and pods used both for nutritional purposes and in traditional medicine to treat various diseases, including hypertension. This review summarizes the evidence, both in animal and human models, about the antihypertensive effects of different parts of M. oleifera, discusses possible mechanisms of action, explores its bioactive compounds with potential antihypertensive properties, and highlights the limitations of its use as a hypotensive agent. Many preclinical studies attribute antihypertensive properties to M. oleifera, particularly the leaves. However, it is premature to draw firm conclusions, as there is a great lack of randomized controlled trials demonstrating its real efficacy. The mechanisms of action and the compounds responsible for the hypotensive effect have not yet been fully elucidated. Therefore, further clinical trials showing its efficacy are strongly required before promoting Moringa for therapeutic purposes. At present, Moringa remains a plant with nutritional and pharmacological potential.

Hydrogen Sulfide-Induced Vasodilation: The Involvement of Vascular Potassium Channels

Hydrogen sulfide (H₂S) has been highlighted as an important gasotransmitter in mammals. A growing number of studies have indicated that H₂S plays a key role in the pathophysiology of vascular diseases and physiological vascular homeostasis. Alteration in H₂S biogenesis has been reported in a variety of vascular diseases and H₂S supplementation exerts effects of vasodilation. Accumulating evidence has shown vascular potassium channels activation is involved in H₂S-induced vasodilation. This review aimed to summarize and discuss the role of H₂S in the regulation of vascular tone, especially by interaction with different vascular potassium channels and the underlying mechanisms.

Antihypertensive effect of Mali-Nil surin rice bran hydrolysate and its mechanisms related to the EDHF-mediated vasorelaxation and L-type Ca2+ channel-mediated vasoconstriction in L-NAME hypertensive rats

Mali-Nil Surin rice bran hydrolysate (MRH) contains highly nutritional proteins and beneficial phenolic compounds. This study investigated an antihypertensive effect of MRH and evaluated the mechanisms mediating this action in N^ω-nitro-L-arginine-methyl ester (L-NAME)-induced hypertensive rats. Antihypertensive activity was determined in male rats orally administered with MRH (100 or 300 mg/kg) or enalapril (15 mg/kg) daily together with L-NAME (50 mg/kg/day) in drinking water, for 21 days. Concurrent oral treatment with MRH lowered the high blood pressure in the L-NAME-induced hypertensive rats. MRH treatment improved endothelial function and increased the endothelium-derived hyperpolarizing factor-mediated vasorelaxation in L-NAME hypertensive rats. L-NAME rats treated with MRH had reduced adrenergic hypercontractility, which was associated with a decrease in L-type calcium channel-mediated vasoconstriction. In addition, MRH exhibited antioxidant activity in hypertensive rats, as indicated by suppression of vascular superoxide anion production and reduction of malondialdehyde levels, as well as magnification of superoxide dismutase and catalase activities in serum. This study demonstrated the nutraceutical potential of MRH to prevent oxidative stress-related vascular dysfunction in hypertension.