title: Myeloperoxidase/nitrite-mediated lipid peroxidation of low-density lipoprotein as modulated by flavonoids.
abstract: In the presence of a H(2)O(2)-generating system, myeloperoxidase (MPO) caused conjugated diene formation in low-density lipoprotein (LDL), indicating lipid peroxidation which was dependent on nitrite but not on chloride. The oxidation of LDL was inhibited by micromolar concentrations of flavonoids such as (-)-epicatechin, quercetin, rutin, taxifolin and luteolin, presumably via scavenging of the MPO-derived NO(2) radical. The flavonoids served as substrates of MPO leading to products with distinct absorbance spectra. The MPO-catalyzed oxidation of flavonoids was accelerated in the presence of nitrite.
authors.affiliation: Institut für Physiologische Chemie I, Universitätsklinikum Düsseldorf, Heinrich-Heine-Universität, P.O. Box 10 10 07, Germany.
authors.forename: Vladimir A
authors.initials: VA
authors.lastname: Kostyuk
authors.forename: Tilo
authors.initials: T
authors.lastname: Kraemer
authors.forename: Helmut
authors.initials: H
authors.lastname: Sies
authors.forename: Tankred
authors.initials: T
authors.lastname: Schewe
mesh_terms: D002392:Catechin / Q000494:pharmacology; D005419:Flavonoids / Q000494:pharmacology*; D006801:Humans; D006861:Hydrogen Peroxide / Q000097:blood / Q000378:metabolism; D007700:Kinetics; D015227:Lipid Peroxidation / Q000502:physiology*; D008077:Lipoproteins, LDL / Q000097:blood* / Q000187:drug effects / Q000378:metabolism*; D009573:Nitrites / Q000378:metabolism*; D009195:Peroxidase / Q000378:metabolism*; D011794:Quercetin / Q000494:pharmacology; D012431:Rutin / Q000494:pharmacology
chemical_list: D005419:Flavonoids; D008077:Lipoproteins, LDL; D009573:Nitrites; C099252:oxidized low density lipoprotein; D012431:Rutin; D002392:Catechin; D011794:Quercetin; D006861:Hydrogen Peroxide; D009195:Peroxidase