title: Glucuronidated and sulfated metabolites of the flavonoid quercetin prevent endothelial dysfunction but lack direct vasorelaxant effects in rat aorta.
abstract: Epidemiological studies have reported an inverse association between dietary flavonoid intake and mortality for ischemic heart disease. Quercetin reduces blood pressure and restores endothelial dysfunction in hypertensive animals. However, quercetin (aglycone) is usually not present in plasma, but it is rapidly metabolized during absorption by methylation, glucuronidation and sulfation. We have analyzed the vasorelaxant effects and the role on NO bioavailability and endothelial function of quercetin and its conjugated metabolites (quercetin-3-glucuronide, isorhamnetin-3-glucuronide and quercetin-3'-sulfate) in rat aorta. Thoracic aortic rings isolated from Wistar rats were mounted for isometric force recording and endothelial function was tested by measuring the vasorelaxant response to acetylcholine. NADPH-enhanced O(2)(-) release was quantified in homogenates from cultured aortic smooth muscle cells using lucigenin chemiluminescence. Unlike quercetin, the conjugated metabolites had no direct vasorelaxant effect, and did not modify endothelial function or the biological activity of NO. However, all metabolites (at 10 micromol/L) prevented, at least partially, the impairment of endothelial-derived NO response under conditions of high oxidative stress induced by the SOD inhibitor DETCA. Furthermore, they protected the biological activity of exogenous NO when impaired by DETCA. Quercetin and quercetin-3'-sulfate (>or=10 micromol/L) or quercetin-3-glucuronide (100 micromol/L) inhibited NADPH oxidase-derived O(2)(-) release. Quercetin and quercetin-3-glucuronide (1 micromol/L) prevented the endothelial dysfunction induced by incubation with ET-1. These data indicate, for the first time, that the conjugated metabolites could be responsible for the in vivo protective activity of quercetin on endothelial dysfunction.
authors.affiliation: Department of Pharmacology, School of Medicine, Universidad Complutense de Madrid, 28040 Madrid, Spain.
authors.forename: Federica
authors.initials: F
authors.lastname: Lodi
authors.forename: Rosario
authors.initials: R
authors.lastname: Jimenez
authors.forename: Laura
authors.initials: L
authors.lastname: Moreno
authors.forename: Paul A
authors.initials: PA
authors.lastname: Kroon
authors.forename: Paul W
authors.initials: PW
authors.lastname: Needs
authors.forename: David A
authors.initials: DA
authors.lastname: Hughes
authors.forename: Celestino
authors.initials: C
authors.lastname: Santos-Buelga
authors.forename: Ana
authors.initials: A
authors.lastname: Gonzalez-Paramas
authors.forename: Angel
authors.initials: A
authors.lastname: Cogolludo
authors.forename: Rocío
authors.initials: R
authors.lastname: Lopez-Sepulveda
authors.forename: Juan
authors.initials: J
authors.lastname: Duarte
authors.forename: Francisco
authors.initials: F
authors.lastname: Perez-Vizcaino
mesh_terms: D000109:Acetylcholine / Q000494:pharmacology; D000818:Animals; D000975:Antioxidants / Q000378:metabolism / Q000494:pharmacology*; D001013:Aorta, Thoracic / Q000187:drug effects / Q000503:physiopathology; D001711:Biotransformation; D004305:Dose-Response Relationship, Drug; D019332:Endothelin-1 / Q000378:metabolism; D004730:Endothelium, Vascular / Q000187:drug effects* / Q000378:metabolism / Q000503:physiopathology; D044948:Flavonols / Q000494:pharmacology; D020719:Glucuronides / Q000378:metabolism / Q000494:pharmacology*; D066298:In Vitro Techniques; D019255:NADPH Oxidases / Q000378:metabolism; D009569:Nitric Oxide / Q000378:metabolism; D018384:Oxidative Stress / Q000187:drug effects; D011794:Quercetin / Q000031:analogs & derivatives / Q000378:metabolism / Q000494:pharmacology*; D051381:Rats; D017208:Rats, Wistar; D013431:Sulfates / Q000378:metabolism / Q000494:pharmacology*; D013481:Superoxides / Q000378:metabolism; D014664:Vasodilation / Q000187:drug effects*; D014665:Vasodilator Agents / Q000378:metabolism / Q000494:pharmacology*
chemical_list: D000975:Antioxidants; D019332:Endothelin-1; D044948:Flavonols; D020719:Glucuronides; D013431:Sulfates; D014665:Vasodilator Agents; C531389:quercetin 3'-sulfate; C443401:quercetin 3-O-glucuronide; C047368:3-methylquercetin; D013481:Superoxides; D009569:Nitric Oxide; D011794:Quercetin; D019255:NADPH Oxidases; D000109:Acetylcholine