title: Cardiovascular inhibitory effects of Hyoscyamus niger.
abstract: This study describes the hypotensive, cardiosuppressant and vasodilator activities of Hyoscyamus niger crude extract (Hn.Cr). Hn.Cr, which tested positive for alkaloids, coumarins, flavonoids, sterols, tannins and terpenes, caused a dose-dependent (10-100 mg/kg) fall in the arterial blood pressure (BP) of rats under anesthesia. In guinea-pig atria, Hn.Cr exhibited a cardiodepressant effect on the rate and force of spontaneous atrial contractions. In isolated rabbit aorta, Hn.Cr (0.01-1.0 mg/ml) relaxed the phenylephrine (PE, 1 microM) and K(+) (80 mM)-induced contractions and suppressed PE (1 microM) control peaks obtained in Ca(++)-free medium similar to that caused by verapamil. The vasodilator effect of Hn.Cr was endothelium-independent as it was not opposed by N (omega)-nitro-L-arginine methyl ester in endothelium-intact rat aortic preparations and also occurred at a similar concentration in endothelium-denuded tissues. These data indicate that Hyoscyamus niger lowers BP through a Ca(++)-antagonist mechanism.
authors.affiliation: Natural Product Research Division, Department of Biological and Biomedical Sciences, The Aga Khan University Medical College, Department of Pharmacology, Faculty of Pharmacy, University of Karachi, Karachi, Pakistan.
authors.forename: A-U
authors.initials: AU
authors.lastname: Khan
authors.forename: A H
authors.initials: AH
authors.lastname: Gilani
mesh_terms: D000818:Animals; D001011:Aorta / Q000187:drug effects / Q000378:metabolism; D001794:Blood Pressure / Q000187:drug effects; D002121:Calcium Channel Blockers / Q000008:administration & dosage / Q000302:isolation & purification / Q000494:pharmacology*; D004305:Dose-Response Relationship, Drug; D004730:Endothelium, Vascular / Q000378:metabolism; D005260:Female; D006168:Guinea Pigs; D006325:Heart Atria / Q000187:drug effects / Q000378:metabolism; D032304:Hyoscyamus / Q000737:chemistry*; D008297:Male; D009200:Myocardial Contraction / Q000187:drug effects; D010936:Plant Extracts / Q000008:administration & dosage / Q000494:pharmacology*; D011817:Rabbits; D051381:Rats; D017207:Rats, Sprague-Dawley; D014665:Vasodilator Agents / Q000008:administration & dosage / Q000302:isolation & purification / Q000494:pharmacology*; D014700:Verapamil / Q000494:pharmacology
chemical_list: D002121:Calcium Channel Blockers; D010936:Plant Extracts; D014665:Vasodilator Agents; D014700:Verapamil