title: Endothelial nitric oxide-dependent vasorelaxant effect of isotirumalin, a dihydroflavonol from Derris urucu, on the rat aorta.
abstract: The present work aimed to investigate the vasorelaxant effect of isotirumalin, a dihydroflavonol isolated from Derris urucu (Leguminosae). The vasorelaxant effect of isotirumalin was investigated in the rat aorta, in the presence and in the absence of a functional endothelium. The production of nitric oxide (NO) induced by isotirumalin was measured simultaneously with its vasorelaxation using carbon microsensors. In endothelium-intact aortic rings, isotirumalin induced a concentration-dependent vasodilator effect the concentration required to produce 30% of relaxation (pIC₃₀=4.84±0.24) that was abolished in endothelium-denuded aortic rings or in the presence of Nω-nitro-L-arginine-methyl-ester (L-NAME; 300 µM). In addition, isotirumalin (100 µM) induced a simultaneous and significant increase on NO production, which was blunted in the presence of L-NAME. The present results demonstrate that isotirumalin is a vasodilator in the rat aorta and act by a mechanism dependent on the presence of a functional endothelium and on NO production.
authors: Departamento de Farmacologia, Instituto de Ciências Biológicas, Universidade Federal de Minas Gerais, Brazil.
authors: Liliane Jorge
authors: LJ
authors: Mendes
authors: Luciano Santos
authors: LS
authors: Capettini
authors: Lívia Trindade
authors: LT
authors: Lôbo
authors: Geilson Alcantara
authors: GA
authors: da Silva
authors: Mara Silvia Pinheiro
authors: MS
authors: Arruda
authors: Virgínia Soares
authors: VS
authors: Lemos
authors: Steyner França
authors: SF
authors: Côrtes
mesh_terms: D000818:Animals; D001011:Aorta / Q000187:drug effects* / Q000502:physiology; D029866:Derris / Q000737:chemistry*; D004730:Endothelium, Vascular / Q000187:drug effects* / Q000502:physiology; D044948:Flavonols / Q000494:pharmacology*; D066298:In Vitro Techniques; D008297:Male; D009569:Nitric Oxide / Q000502:physiology*; D051381:Rats; D017208:Rats, Wistar; D014665:Vasodilator Agents / Q000494:pharmacology*
chemical_list: C568924:5,3'-dihydroxy-6-(3-methylbut-2-enyl)-7,4'-dimethoxydihydroflavonol; D044948:Flavonols; D014665:Vasodilator Agents; D009569:Nitric Oxide