Effects of cocoa extracts on endothelium-dependent relaxation.
The aim of this study was to examine the effects of procyanidins derived from cocoa on vascular smooth muscle. Two hypotheses were tested: 1) extracts of cocoa, which are rich in procyanidins, cause endothelium-dependent relaxation (EDR), and 2) extracts of cocoa activate endothelial nitric oxide synthase (NOS). The experiments were carried out on aortic rings obtained from New Zealand White rabbits. The polymeric procyanidins (tetramer through decamer of catechin) caused an EDR. In addition, the Ca(2+)-dependent NOS activity, measured by the L-arginine to L-citrulline conversion assay, was significantly increased in aortic endothelial cells exposed to polymeric procyanidins, whereas monomeric compounds had no such effect. These findings demonstrate that polymeric procyanidins cause an EDR that is mediated by activation of NOS.
Department of Internal Medicine, University of California Davis, California 95616-8636, USA.
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Karim
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McCormick
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Kappagoda
D000818:Animals; D001011:Aorta; D001120:Arginine / Q000378:metabolism; D044946:Biflavonoids; D002099:Cacao / Q000502:physiology*; D002392:Catechin / Q000302:isolation & purification / Q000494:pharmacology*; D004347:Drug Interactions; D004730:Endothelium, Vascular / Q000187:drug effects*; D004789:Enzyme Activation / Q000187:drug effects; D004791:Enzyme Inhibitors / Q000494:pharmacology; D009126:Muscle Relaxation / Q000187:drug effects*; D009131:Muscle, Smooth, Vascular / Q000187:drug effects* / Q000201:enzymology; D019331:NG-Nitroarginine Methyl Ester / Q000494:pharmacology; D019001:Nitric Oxide Synthase / Q000096:biosynthesis*; D044945:Proanthocyanidins; D011817:Rabbits; D013329:Structure-Activity Relationship
D044946:Biflavonoids; D004791:Enzyme Inhibitors; D044945:Proanthocyanidins; C017674:procyanidin; D002392:Catechin; D001120:Arginine; D019001:Nitric Oxide Synthase; D019331:NG-Nitroarginine Methyl Ester