Atividade vascular e anti-hipertensiva de uma fração polifenólica de Inga edulis Mart

Abstract

Hypertension is a multifactorial clinical condition that has a high prevalence and low control rate. The effective antihypertensive therapy markedly reduces morbidity and mortality due to cardiovascular disease. The consumption of polyphenols reduce the risk rate of cardiovascular diseases, as demonstrated by epidemiological studies. Polyphenols are vasodilator compounds acting through several mechanisms of action, including the formation of nitric oxide (NO) by vascular endothelial cells. This effect may result on reduction of vascular resistance and decrease on blood pressure. The present work aimed to evaluate the antihypertensive and to investigate the vasodilator effects and mechanisms of a polyphenolic fraction obtained from the leaves of Inga edulis (IPF) and of the pure compounds present in this fraction. In rat aorta pre-contracted with phenylephrine, IPF induces vasodilatation in a concentration- dependent manner and dependent on the presence of a functional endothelium. Using enzyme inhibitors and antagonists of the receptors we found that the vasodilator mechanism of action is dependent of the Src/PI3k and NO/cGMP pathways. Furthermore, it was shown the participation of estrogen receptors, subtype ER. Substances catechin and myricetin, present in high concentration in IPF, contributed to the vasodilator effect, although other polyphenolic compounds may also have a synergic effect. IPF, via intraperitonial and oral routes, presented an antihypertensive effect in DOCA-Salt hypertensive rats. By using the serum nitrite measurement it was observed that IPF is capable of inducing an increase in the production of NO, which is probably the responsible for the reduction of blood pressure. Together these results allow us to conclued that IPF has an antihypertensive effect dependent on its vasodilator effect and on production of NO throught a mechanism involving activation of ER and Src/PI3K pathways. Allthogether, the present work demonstrates that the standardized fraction rich in polyphenolic compounds obtained from the species I. edulis has a great potential for the treatment of cardiovascular diseases, particularly systemic arterial hypertension.