title: Cardiovascular activity of the n-butanol fraction of the methanol extract of Loranthus ferrugineus Roxb.
abstract: We investigated the vascular responses and the blood pressure reducing effects of different fractions obtained from the methanol extract of Loranthus ferrugineus Roxb. (F. Loranthaceae). By means of solvent-solvent extraction, L. ferrugineus methanol extract (LFME) was successively fractionated with chloroform, ethyl acetate and n-butanol. The ability of these LFME fractions to relax vascular smooth muscle against phenylephrine (PE)- and KCl-induced contractions in isolated rat aortic rings was determined. In another set of experiments, LFME fractions were tested for blood pressure lowering activity in anesthetized adult male Sprague-Dawley rats (250-300 g, 14-18 weeks). The n-butanol fraction of LFME (NBF-LFME) produced a significant concentration-dependent inhibition of PE- and KCl-induced aortic ring contractions compared to other fractions. Moreover, NBF-LFME had a significantly higher relaxant effect against PE- than against high K+-induced contractions. In anesthetized Sprague-Dawley rats, NBF-LFME significantly lowered blood pressure in a dose-dependent manner and with a relatively longer duration of action compared to the other fractions. HPLC, UV and IR spectra suggested the presence of terpenoid constituents in both LFME and NBF-LFME. Accordingly, we conclude that NBF-LFME is the most potent fraction producing a concentration-dependent relaxation in vascular smooth muscle in vitro and a dose-dependent blood pressure lowering activity in vivo. The cardiovascular effects of NBF-LFME are most likely attributable to its terpenoid content.
authors.affiliation: Department of Physiology and Pharmacology, Universiti Sains Malaysia, Penang, Malaysia. omar_3m@yahoo.com
authors.forename: O Z
authors.initials: OZ
authors.lastname: Ameer
authors.forename: I M
authors.initials: IM
authors.lastname: Salman
authors.forename: M J A
authors.initials: MJ
authors.lastname: Siddiqui
authors.forename: M F
authors.initials: MF
authors.lastname: Yam
authors.forename: R N
authors.initials: RN
authors.lastname: Sriramaneni
authors.forename: A
authors.initials: A
authors.lastname: Sadikun
authors.forename: Z
authors.initials: Z
authors.lastname: Ismail
authors.forename: A M
authors.initials: AM
authors.lastname: Shah
authors.forename: M Z
authors.initials: MZ
authors.lastname: Asmawi
mesh_terms: D020001:1-Butanol / Q000302:isolation & purification / Q000494:pharmacology*; D000818:Animals; D001013:Aorta, Thoracic / Q000187:drug effects; D001794:Blood Pressure / Q000187:drug effects*; D002851:Chromatography, High Pressure Liquid; D028183:Loranthaceae / Q000737:chemistry*; D008297:Male; D000432:Methanol / Q000302:isolation & purification / Q000494:pharmacology; D009131:Muscle, Smooth, Vascular / Q000187:drug effects*; D010936:Plant Extracts / Q000494:pharmacology*; D051381:Rats; D017207:Rats, Sprague-Dawley; D014664:Vasodilation / Q000187:drug effects*
chemical_list: D010936:Plant Extracts; D020001:1-Butanol; D000432:Methanol