title: Structure and vasorelaxant activity of floranol, a flavonoid isolated from the roots of Dioclea grandiflora.
abstract: The structure of the prenylated flavanonol, floranol (1=(2R,3R)-3,5,7-trihydroxy-2-(2-hydroxyphenyl)-6-methoxy-8-(3-methylbut-2-enyl)-4H-1-benzopyran-4-one), isolated from the roots of Dioclea grandiflora (Fabaceae), was unambiguously determined by X-ray analysis. The compound was tested for vasorelaxant activity. In endothelium-containing aortic rings, floranol (1) induced a concentration-dependent vasodilator effect in vessels precontracted with 0.1 microM phenylephrine with an IC(50) value of 19.9+/-2.4 microM. The removal of endothelium or pretreatment of vessels with the NO-synthase inhibitor L-NAME did not change the IC(50) and E(max) values for floranol-induced vasorelaxation. We conclude that floranol (1) should be acting directly in the rat-aorta smooth muscle cells to produce its vasorelaxant effect. The structure-activity relationship was discussed in terms of the 3-D floranol structure determined by X-ray crystallography.
authors.affiliation: Departamento de Fisiologia e Biofísica, Universidade Federal de Minas Gerais, 31270-901, Belo Horizonte--MG, Brazil.
authors.forename: Virgínia S
authors.initials: VS
authors.lastname: Lemos
authors.forename: Steyner F
authors.initials: SF
authors.lastname: Côrtes
authors.forename: Marcelo H
authors.initials: MH
authors.lastname: dos Santos
authors.forename: Javier
authors.initials: J
authors.lastname: Ellena
authors.forename: Maria E C
authors.initials: ME
authors.lastname: Moreira
authors.forename: Antônio C
authors.initials: AC
authors.lastname: Doriguetto
mesh_terms: D001011:Aorta / Q000187:drug effects; D018360:Crystallography, X-Ray; D052598:Dioclea / Q000737:chemistry*; D005419:Flavonoids / Q000737:chemistry* / Q000302:isolation & purification / Q000494:pharmacology*; D006860:Hydrogen Bonding; D008958:Models, Molecular; D015394:Molecular Structure; D018517:Plant Roots / Q000737:chemistry*; D014664:Vasodilation / Q000187:drug effects*; D014665:Vasodilator Agents / Q000737:chemistry* / Q000302:isolation & purification / Q000494:pharmacology*
chemical_list: D005419:Flavonoids; D014665:Vasodilator Agents; C488030:floranol