The flavanol (-)-epicatechin has been found to protect against damage inflicted by peroxynitrite, an inflammatory intermediate. Here, epicatechin was tested in systems of increasing complexity. The compound efficiently protected against nitration of protein tyrosine residues by peroxynitrite (IC(50) approximately 0.02 mol epicatechin/mol peroxynitrite). However, at epicatechin concentrations completely preventing nitration of tyrosine by peroxynitrite, protection against the oxidative inactivation of glyceraldehyde-3-phosphate dehydrogenase or soybean lipoxygenase-1 was marginal (IC(50) > 1 mol epicatechin/mol peroxynitrite), approximately two orders of magnitude less. Likewise, epicatechin was relatively ineffective against oxidation of thiols in cell lysates, and against the oxidation of 2',7'-dichlorodihydrofluorescein in cultured cells. The activation of the kinases Akt/protein kinase B, ERK1/2 and p38-MAPK by peroxynitrite in murine aorta endothelial cells was not altered by epicatechin, suggesting that activation of these kinases is due to processes other than tyrosine nitration.
The following library presently contains abstracts of the journal articles published by Mars, Incorporated scientists or other scientists who have used Cocoapro® cocoa supplied by Mars, Incorporated. As the site continues to evolve, abstracts of additional peer-reviewed papers from all cocoa literature will be added.
