title: 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 (10-300 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, N(ω)-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 R-R 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.
authors.affiliation: Natural Products Research Division, Department of Biological and Biomedical Sciences, The Aga Khan University Medical College, Karachi, Pakistan.
authors.forename: Munasib
authors.initials: M
authors.lastname: Khan
authors.forename: Arif-Ullah
authors.initials: AU
authors.lastname: Khan
authors.lastname: Najeeb-ur-Rehman
authors.forename: Muhammad Abdullah
authors.initials: MA
authors.lastname: Zafar
authors.forename: Ali
authors.initials: A
authors.lastname: Hazrat
authors.forename: Anwarul-Hassan
authors.initials: AH
authors.lastname: Gilani
mesh_terms: D000818:Animals; D000959:Antihypertensive Agents / Q000494:pharmacology; D001013:Aorta, Thoracic / Q000187:drug effects; D001794:Blood Pressure / Q000187:drug effects; D002121:Calcium Channel Blockers / Q000494:pharmacology; D002317:Cardiovascular Agents / Q000494:pharmacology*; D004562:Electrocardiography; D005260:Female; D006168:Guinea Pigs; D006325:Heart Atria / Q000187:drug effects; D066298:In Vitro Techniques; D018653:Juniperus / Q000737:chemistry; D008297:Male; D009200:Myocardial Contraction / Q000187:drug effects; D010936:Plant Extracts / Q000494:pharmacology; D010946:Plants, Medicinal / Q000737:chemistry; D011817:Rabbits; D051381:Rats; D017207:Rats, Sprague-Dawley; D014665:Vasodilator Agents / Q000494:pharmacology
chemical_list: D000959:Antihypertensive Agents; D002121:Calcium Channel Blockers; D002317:Cardiovascular Agents; D010936:Plant Extracts; D014665:Vasodilator Agents