Inhibition of platelet aggregation and arachidonate metabolism in platelets by procyanidins.
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.
Chang
W C
WC
Department of Pharmacology, College of Medicine, National Cheng Kung University, Tainan, Taiwan.
Hsu
F L
FL
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
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