Reactions of peroxynitrite with cocoa procyanidin oligomers

Peroxynitrite is a mediator molecule in inflammation, and its biological pr operties are being studied extensively. Flavonoids, which are natural plant constituents, protect against peroxynitrite and thereby could play an anti -inflammatory role. Procyanidin oligomers of different sizes (monomer throu gh nonamer), isolated from the seeds of Theobroma cacao, were recently exam ined for their ability to protect against peroxynitrite-dependent oxidation of dihydrorhodamine 123 and nitration of tyrosine and were found to be eff ective in attenuating these reactions. The tetramer was particularly effici ent at protecting against oxidation and nitration reactions. Epicatechin ol igomers found in cocoa powder and chocolate may be a potent dietary source for defense against peroxynitrite.