Vasodilator response to Psidium guajave leaves of mesenteric bed vessels from diabetic and non-diabetic rats

Mortality from cardiovascular abnormalities is almost three times more prevalent in the diabetic population than that in the general population. Psidium guajave has been used traditionally for a long time as a medicinal herb to cure diabetes. Endothelial dependent vasorelaxation effect of Psidium guajave extract on normal aortic rings was observed. This study was designed to investigate the endothelium and nitric oxide roles inPGE-induced vasorelaxation in diabetic rat vessel. Diabetes was induced by a single intraperitoneal injection of streptozotocin. Eight weeks later, superior mesenteric arteries of non-diabetic and diabetic groups were isolated and perfused according to the McGregor method. Prepared vascular beds were constricted with phenylephrine to induce 70% - 75% of maximal constriction. Psidium guajave extract at concentrations of 0.1 to 4 mg/100ml added to the medium and perfusion pressure was recorded. Baseline perfusion pressure of diabetic group was significantly higher than non-diabetic rats in both intact and denuded endothelium. Psidium guajave extract caused a significantly dose depended decrease in perfusion pressure in non-diabetic and diabetic groups in both intact and denuded endothelium. In the presence of N (ω)-nitro-L-arginine methyl ester, Psidium guajave ex-tractinduced relaxation in intact mesenteric beds of non-diabetic and diabetic animals was not suppressed. From the results of this study, it may be concluded that vasorelaxatory effect of Psidium guajave extract is not mediated by endothelium and nitric oxide in both diabetic and non-diabetic vessel and supports the use of the plant’s leaves as a natural, adjunct phytomedicine in the management of diabetes vessel complications.