title: Endothelium-dependent vasorelaxant effects of the essential oil from aerial parts of Alpinia zerumbet and its main constituent 1,8-cineole in rats.
abstract: Vasorelaxant effects of essential oil of Alpinia zerumbet (EOAZ) and its main constituent, 1,8-cineole (CIN) were studied. In rat isolated aorta preparations with intact endothelium, EOAZ (0.01-3000 microg/ml) induced significant but incomplete relaxation of the phenylephrine-induced contraction, an effect that was abolished by removal of vascular endothelium. However, at the same concentrations (0.01-3000 microg/ml corresponding to 0.0000647-19.5 mM), CIN induced a complete vasorelaxant effects (IC(50)=663.2+/-63.8 microg/ml) that were significantly reduced in endothelium-denuded rings (IC(50)=1620.6+/-35.7 microg/ml). Neither EOAZ nor CIN affected the basal tonus of isolated aorta. Vasorelaxant effects of both EOAZ and CIN remained unaffected by the addition of tetraethylamonium chloride (500 microM) or indomethacin (10 microM) into the bath, but were significantly reduced by N(G)-nitro-L-arginine methyl ester (100 microM). It is concluded that EOAZ induces a potent vasorelaxant effect that could not be fully attributed to the actions of the main constituent CIN, and appears totally dependent on the integrity of a functional vascular endothelium. The data is novel and corroborate the popular use of A. zerumbet for the treatment of hypertension.
authors.affiliation: Instituto Superior de Ciências Biomédicas, Universidade Estadual do Ceará, Fortaleza, CE, Brazil.
authors.forename: Nilson V
authors.initials: NV
authors.lastname: Pinto
authors.forename: Ana Maria S
authors.initials: AM
authors.lastname: Assreuy
authors.forename: Andrelina N
authors.initials: AN
authors.lastname: Coelho-de-Souza
authors.forename: Vania M
authors.initials: VM
authors.lastname: Ceccatto
authors.forename: Pedro Jorge C
authors.initials: PJ
authors.lastname: Magalhães
authors.forename: Saad
authors.initials: S
authors.lastname: Lahlou
authors.forename: José Henrique
authors.initials: JH
authors.lastname: Leal-Cardoso
mesh_terms: D032429:Alpinia / Q000737:chemistry*; D000818:Animals; D001011:Aorta; D002317:Cardiovascular Agents / Q000494:pharmacology; D003511:Cyclohexanols / Q000494:pharmacology*; D004730:Endothelium, Vascular / Q000187:drug effects*; D000077591:Eucalyptol; D007213:Indomethacin / Q000494:pharmacology; D008297:Male; D039821:Monoterpenes / Q000494:pharmacology*; D019331:NG-Nitroarginine Methyl Ester / Q000494:pharmacology; D009822:Oils, Volatile / Q000494:pharmacology*; D010656:Phenylephrine; D035261:Plant Components, Aerial; D010936:Plant Extracts / Q000494:pharmacology*; D018515:Plant Leaves; D051381:Rats; D019789:Tetraethylammonium / Q000494:pharmacology; D014661:Vasoconstriction / Q000187:drug effects*; D014664:Vasodilation / Q000187:drug effects; D014665:Vasodilator Agents / Q000494:pharmacology*
chemical_list: D002317:Cardiovascular Agents; D003511:Cyclohexanols; D039821:Monoterpenes; D009822:Oils, Volatile; D010936:Plant Extracts; D014665:Vasodilator Agents; D010656:Phenylephrine; D019789:Tetraethylammonium; D000077591:Eucalyptol; D019331:NG-Nitroarginine Methyl Ester; D007213:Indomethacin