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Myeloperoxidase‐induced lipid peroxidation of LDL in the presence of nitrite. Protection by cocoa flavanols
Author(s) -
Schewe Tankred,
Sies Helmut
Publication year - 2005
Publication title -
biofactors
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.204
H-Index - 94
eISSN - 1872-8081
pISSN - 0951-6433
DOI - 10.1002/biof.5520240106
Subject(s) - myeloperoxidase , chemistry , peroxynitrite , nitric oxide , nitrite , biochemistry , lipid peroxidation , low density lipoprotein , antioxidant , cholesterol , enzyme , medicine , superoxide , inflammation , organic chemistry , nitrate
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.