Polyphenols of cocoa: Inhibition of mammalian 15-lipoxygenase

Tankred Schewe, Christian Sadik, Lars Oliver Klotz, Tanihiro Yoshimoto, Hartmut Kühn, Helmut Sies*

*Corresponding author for this work
106 Citations (Scopus)


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 μM. Among the monomeric flavanols, epigallocatechin gallate (IC50 = 4μM) and epicatechin gallate (5 μM) were more potent than (-)-epicatechin (IC50 = 60 μM). (-)-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. 15μM) 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.

Original languageEnglish
JournalBiological Chemistry
Issue number12
Pages (from-to)1687-1696
Number of pages10
Publication statusPublished - 01.12.2001


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