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Editorial

Beetroot Juice May Be a Dietary Ingredient to Protect Vascular Endothelium

The first Dietary Recommendations originated in 1941 by order of President Franklin Roosevelt, when he convened the “National Conference on Nutrition in Defense” to guarantee a population fit for war, minimizing diseases due to deficiency of nutrients.In the same year, the American Medical Association declared that “nutrition research should be encouraged” with primary objectives of “estimating the amounts of essential nutrients in foods,” “detection of nutritional deficiency states,” and more precise determination of “optimal and minimum requirements” for each nutrient.

In humans, after absorption through the stomach wall, 25% of the nitrate consumed enters the entero-salivary circulation, where it is reduced to nitrite (NO₂) by bacterial nitrate reductases of facultative anaerobes on the dorsal surface of the tongue.^,This nitrite is swallowed and, in the stomach’s acidic environment, is reduced to nitric oxide (NO) or re-enters the circulation as nitrite. Thus, dietary nitrate may represent an intravascular source of the pleiotropic vasoprotective molecule NO and acts as a potent dilator of blood pressure and delays atherogenesis by inhibiting the recruitment of inflammatory cells and platelet aggregation. Thus, protecting the vascular endothelium influences numerous cardiovascular pathologies (prehypertension, hypertension, atherosclerosis, and stroke) associated with endothelial dysfunction and decreased NObioactivity. Recently, studies have shown that nitrite confers marked protection against ischemia/reperfusion (I/R) injury to the myocardium, kidney, lung, and cerebral vasculature.^,

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Original Article

Effect of Diterpene Manool on the Arterial Blood Pressure and Vascular Reactivity in Normotensive and Hypertensive Rats

Ariadne Santana e Neves Monteiro et al. Debora Ribeiro Campos Agnes Afrodite Sumarelli Albuquerque Paulo Roberto Barbosa Evora … Luciana Garros Ferreira Andrea Carla Celotto

Abstract

Background:

Many studies have shown that the diterpenoid classes exert a significant effect on the cardiovascular system. Diterpenes, in particular, are among the main compound links to cardiovascular properties such as vasorelaxant, inotropic, diuretic and hypotensive activity. While the manool vasorelaxation mechanism is visible, its effect on blood pressure (BP) is still unknown.

Objective:

To evaluate the in vivo hypotensive effect of manool and check the ex vivo vasorelaxation effect in rat aortic rings.

Methods:

The animals were divided randomly into two groups: normotensive and hypertensive. The normotensive group was sham-operated, and the 2K1C model was adopted for the hypertensive group. Invasive BP monitoring was performed for manool tests at different doses (10, 20 and 40 mg/kg). Concentration-response curves for manool were obtained in the aorta rings, with endothelium, pre-contracted with phenylephrine (Phe) after incubation with Nω-nitro-L-arginine methyl ester(L-NAME) or oxadiazole [4,3-a]quinoxalin-1-one (ODQ). Nitric oxide (NOx) plasma levels were measured by chemiluminescence assay.

Results:

After manool administration, BP was reduced in normotensive and hypertensive groups, and this effect was inhibited by L-NAME in hypertensive animals only in 10 mg/kg dose. Ex vivo manool promoted vasorelaxation, which was inhibited by L-NAME and ODQ incubation or endothelium removal. NOx plasma levels increased in the hypertensive group after manool administration. Manool elicits endothelium-dependent vascular relaxation in rat aorta mediated by the NO/cGMP signaling pathway and BP reduction, also by NOx plasma increase. These combined effects could be involved in modulating peripheral resistance, contributing to the antihypertensive effect of diterpene.

Conclusion:

These effects together could be involved in modulating peripheral resistance, contributing to the antihypertensive effect of diterpene.