Some cocoas and chocolates are rich in (-)-epicatechin and its related oligomers, the procyanidins. Fractions of these compounds, isolated from the seeds of Theobroma cacao, caused dose-dependent inhibition of isolated rabbit 15-lipoxygenase-1 with the larger oligomers being more active; the decamer fraction revealed an IC50 of 0.8 microM. Among the monomeric flavanols, epigallocatechin gallate (IC50 = 4 microM) and epicatechin gallate (5 microM) were more potent than (-)-epicatechin (IC50 = 60 microM). (-)-Epicatechin and procyanidin nonamer also inhibited the formation of 15-hydroxy-eicosatetraenoic acid from arachidonic acid in rabbit smooth muscle cells transfected with human 15-lipoxygenase-1. In contrast, inhibition of the lipoxygenase pathway in J774A.1 cells transfected with porcine leukocyte-type 12-lipoxygenase (another representative of the 12/15-lipoxygenase family) was only observed upon sonication of the cells, suggesting a membrane barrier for flavanols in these cells. Moreover, epicatechin (IC50 approx. 15 microM) and the procyanidin decamer inhibited recombinant human platelet 12-lipoxygenase. These observations suggest general lipoxygenase-inhibitory potency of flavanols and procyanidins that may contribute to their putative beneficial effects on the cardiovascular system in man. Thus, they may provide a plausible explanation for recent literature reports indicating that procyanidins decrease the leukotriene/prostacyclin ratio in humans and human aortic endothelial cells.
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.
