title: Inhibitory effects of glycosides from the leaves of Melaleuca quinquenervia on vascular contraction of rats.
abstract: Two new glycosides, 3-hydroxy-5-methoxy-4-methylphenyl beta-D-glucopyranoside (1) and 4-benzoyl-2-C-beta-glucopyranosyl-3,5-dihydroxy-6-methylphenyl beta-D-glucopyranoside (2), together with four known glycosides, 2-endo-beta-D-glucopyranosyloxy-1,8-cineole (3a), 2-exo-beta-D-glucopyranosyloxy-1,8-cineole (3b), roseoside (4), and citroside A (5), were isolated from the methanolic extract of leaves of Melaleuca quinquenervia. Their structures were elucidated on the basis of spectroscopic analysis. Compounds 1, 2a and 3 inhibited contractile response induced by phenylephrine in aortic rings from Sprague-Dawley rats. This inhibition was independent of the endothelium. Compounds 2 and 4 significantly relaxed precontracted aortic rings, in an endothelium-dependent manner. Pretreatment of N(omega)-nitro-L-arginine (L-NNA), a nitric oxide synthase inhibitor, partially attenuated the vasorelaxation induced by both compounds, suggesting that nitric oxide was likely the responsible mediator. The rank-order potency (EC 50 value) of vasorelaxing activities of these compounds is 4 > 2 > 2a > 3 > 1.
authors.affiliation: Institute of Botany, Academia Sinica, Nankang, Taipei, Taiwan, ROC.
authors.forename: Tzong-Huei
authors.initials: TH
authors.lastname: Lee
authors.forename: Guei-Jane
authors.initials: GJ
authors.lastname: Wang
authors.forename: Ching-Kuo
authors.initials: CK
authors.lastname: Lee
authors.forename: Yueh-Hsiung
authors.initials: YH
authors.lastname: Kuo
authors.forename: Chang-Hung
authors.initials: CH
authors.lastname: Chou
mesh_terms: D000818:Animals; D001013:Aorta, Thoracic / Q000187:drug effects; D004187:Disaccharides / Q000737:chemistry / Q000302:isolation & purification / Q000494:pharmacology*; D004305:Dose-Response Relationship, Drug; D004730:Endothelium, Vascular / Q000502:physiology; D005960:Glucosides / Q000302:isolation & purification / Q000494:pharmacology; D006027:Glycosides / Q000737:chemistry / Q000302:isolation & purification / Q000494:pharmacology*; D009005:Monosaccharides / Q000737:chemistry / Q000302:isolation & purification / Q000494:pharmacology*; D027822:Myrtaceae; D009569:Nitric Oxide / Q000378:metabolism; D019001:Nitric Oxide Synthase / Q000037:antagonists & inhibitors; D019335:Nitroarginine / Q000494:pharmacology; D045792:Norisoprenoids; D010656:Phenylephrine / Q000494:pharmacology; D010936:Plant Extracts / Q000737:chemistry / Q000494:pharmacology*; D018515:Plant Leaves / Q000737:chemistry*; D051381:Rats; D017207:Rats, Sprague-Dawley; D014661:Vasoconstriction / Q000187:drug effects*; D014664:Vasodilation / Q000187:drug effects
chemical_list: C465060:2-endo-glucopyranosyloxy-1,8-cineole; C465058:3-hydroxy-5-methoxy-4-methylphenyl-glucopyranoside; C465059:4-benzoyl-2-C-glucopyranosyl-3,5-dihydroxy-6-methylphenyl-glucopyranoside; D004187:Disaccharides; D005960:Glucosides; D006027:Glycosides; D009005:Monosaccharides; D045792:Norisoprenoids; D010936:Plant Extracts; C438027:roseoside; D010656:Phenylephrine; D019335:Nitroarginine; D009569:Nitric Oxide; D019001:Nitric Oxide Synthase