Cardiovascular effects of juniperus excelsa are mediated through multiple pathways

Abstract

Juniperus excelsa Bieb. is used in folk medicine for lowering blood pressure (BP). Its BP-lowering effect, endothelium-dependent and endothelium-independent vasodilator effects, and cardio-modulatory effect are reported here. The crude extract of J. excelsa (Je.Cr) which tested positive for the presence of anthraquinone, flavonoids, saponins, sterols, terpenes, and tannins induced a dose-dependent (10300 mg/kg) fall in the arterial BP of anesthetized rats. In isolated rabbit aorta, Je.Cr (0.01-5.0 mg/mL) inhibited high K + (80 mM)- and phenylephrine (1 μM)-induced contractions, like that caused by verapamil and papaverine. In endothelium-intact rat aortic preparations, Nω-nitro-l-arginine methyl ester hydrochloride-sensitive vasodilator activity was noted from Je.Cr, which also relaxed the endothelium-denuded aorta tissues. In guinea pig atria, Je.Cr initially caused mild cardiac stimulation, followed by inhibition, like that exhibited by papaverine. Je.Cr prolonged the RR interval in electrocardiogram of rats under anesthesia. These results reveal that cardiovascular effects of J. excelsa are mediated possibly through a combination of Ca ++ antagonism, nitric oxide-modulating mechanism, and phosphodiesterase inhibitory mechanism, which explain its medicinal use in hypertension. © 2012 Informa Healthcare USA, Inc.