Affiliations: Institut für Biochemie und Molekularbiologie I,
Heinrich-Heine-Universität Düsseldorf, Düsseldorf, Germany
Note: [] Address for correspondence: Prof. Dr. T. Schewe, Institut
für Biochemie und Molekularbiologie I, Postfach 101007, D-40001
Düsseldorf, Germany. Tel.: +49 211 811 5247; Fax: +49 211 811 3029;
E-mail: [email protected]
Abstract: Lipid peroxidation (LPO) of low-density lipoprotein (LDL) is
believed to be a pivotal process rendering this plasma lipoprotein atherogenic.
Several endogenous factors have been proposed to mediate LPO of LDL, among them
myeloperoxidase (MPO), which is active in atherosclerotic lesions, and the
plasma level of which has been proposed to be a prognostic parameter for
cardiac events. Nitrite, a major oxidation product of nitric oxide, is
substrate of MPO and a cofactor of MPO-mediated LPO under physiological
conditions. Dietary flavonoids including (−)-epicatechin, a major
flavan-3-ol in cocoa products, grapes and wine, are substrates of MPO as well
as potent inhibitors of LPO in LDL at micromolar concentrations. Moreover, they
strongly suppress protein tyrosine nitration of LDL by MPO/nitrite or
peroxynitrite. By blunting undesirable MPO-mediated actions of nitrite,
presumably via scavenging of the strong prooxidant and nitrating
^{˙}NO_2 radical, dietary
flavonoids modulate NO metabolism in a favorable direction and thus counteract
endothelial dysfunction. This article gives a survey on recent progress in this
field with special reference to own recently published work.
Keywords: Antioxidants, atherosclerosis, catechins, epicatechin, flavonoids, NO, peroxynitrite, polyphenols, protein tyrosine nitration
Journal: BioFactors, vol. 24, no. 1-4, pp. 49-58, 2005
