title: Inhibition of platelet aggregation and arachidonate metabolism in platelets by procyanidins.
abstract: The effects of procyanidins on platelet aggregation and arachidonate metabolism in platelets were studied. Nine procyanidins were used in this investigation. Procyanidins B-2-S, EEC and C-1 significantly induced the inhibition of platelet aggregation, and the potency of inhibition was comparable with aspirin. Procyanidin B-2-S was used as a representative of procyanidins for further studies on the effect on arachidonate metabolism. In arachidonate metabolism by fatty acid cyclooxygenase pathway, B-2-S inhibited TXB2 and HHT formation by intact platelets treated with exogenous arachidonic acid. It also inhibited TXB2 formation measured by a specific radioimmunoassay when the cells were challenged with calcium ionophore A23187. In cell-free system, B-2-S inhibited both TXB2 and 12-HETE bioxynthesis in platelet microsome and cytosol, respectively. The inhibitory effect on thromboxane biosynthesis might explain the inhibitory effect of procyanidins on platelet aggregation.
authors.affiliation: Department of Pharmacology, College of Medicine, National Cheng Kung University, Tainan, Taiwan.
authors.forename: W C
authors.initials: WC
authors.lastname: Chang
authors.forename: F L
authors.initials: FL
authors.lastname: Hsu
mesh_terms: D000818:Animals; D001092:Arachidonate 12-Lipoxygenase / Q000378:metabolism; D016718:Arachidonic Acid; D001095:Arachidonic Acids / Q000097:blood*; D044946:Biflavonoids; D001711:Biotransformation; D001792:Blood Platelets / Q000187:drug effects / Q000378:metabolism*; D001798:Blood Proteins / Q000378:metabolism; D002392:Catechin / Q000494:pharmacology*; D002474:Cell-Free System; D003600:Cytosol / Q000378:metabolism; D066298:In Vitro Techniques; D008297:Male; D008861:Microsomes / Q000378:metabolism; D010974:Platelet Aggregation / Q000187:drug effects*; D010975:Platelet Aggregation Inhibitors; D044945:Proanthocyanidins; D011817:Rabbits; D011863:Radioimmunoassay; D012710:Serum Albumin, Bovine
chemical_list: D001095:Arachidonic Acids; D044946:Biflavonoids; D001798:Blood Proteins; D010975:Platelet Aggregation Inhibitors; D044945:Proanthocyanidins; C479578:procyanidin B; D012710:Serum Albumin, Bovine; D016718:Arachidonic Acid; C017674:procyanidin; D002392:Catechin; D001092:Arachidonate 12-Lipoxygenase