title: Antiplatelet effect of marchantinquinone, isolated from Reboulia hemisphaerica, in rabbit washed platelets.
abstract: Platelet activation is involved in serious pathological situations, including atherosclerosis and restenosis. It is important to find efficient antiplatelet medicines to prevent fatal thrombous formation during the course of these diseases. Marchantinquinone, a natural compound isolated from Reboulia hemisphaerica, inhibited platelet aggregation and ATP release stimulated by thrombin (0.1 units mL(-1)), platelet-activating factor (PAF; 2 ng mL(-1)), collagen (10 microg mL(-1)), arachidonic acid (100 microM), or U46619 (1 microM) in rabbit washed platelets. The IC50 values of marchantinquinone on the inhibition of platelet aggregation induced by these five agonists were 62.0 +/- 9.0, 86.0 +/- 7.8, 13.6 +/- 4.7, 20.9 +/- 3.1 and 13.4 +/- 5.3 microM, respectively. Marchantinquinone inhibited thromboxane B2 (TxB2) formation induced by thrombin, PAF or collagen. However, marchantinquinone did not inhibit TxB2 formation induced by arachidonic acid, indicating that marchantinquinone did not affect the activity of cyclooxygenase and thromboxane synthase. Marchantinquinone did inhibit the rising intracellular Ca2+ concentration stimulated by the five platelet-aggregation inducers. The formation of inositol monophosphate induced by thrombin was inhibited by marchantinquinone. Platelet cAMP and cGMP levels were unchanged by marchantinquinone. The results indicate that marchantinquinone exerts antiplatelet effects by inhibiting phosphoinositide turnover.
authors.affiliation: Pharmacological Institute, College of Medicine, National Taiwan University, Taipei.
authors.forename: C H
authors.initials: CH
authors.lastname: Liao
authors.forename: F N
authors.initials: FN
authors.lastname: Ko
authors.forename: C L
authors.initials: CL
authors.lastname: Wu
authors.forename: C M
authors.initials: CM
authors.lastname: Teng
mesh_terms: D019796:15-Hydroxy-11 alpha,9 alpha-(epoxymethano)prosta-5,13-dienoic Acid / Q000494:pharmacology; D000255:Adenosine Triphosphate / Q000378:metabolism; D000818:Animals; D016718:Arachidonic Acid / Q000494:pharmacology; D001632:Bibenzyls / Q000737:chemistry / Q000494:pharmacology*; D001792:Blood Platelets / Q000187:drug effects* / Q000378:metabolism; D002118:Calcium / Q000378:metabolism; D003094:Collagen / Q000494:pharmacology; D000242:Cyclic AMP / Q000378:metabolism; D006152:Cyclic GMP / Q000378:metabolism; D004305:Dose-Response Relationship, Drug; D004988:Ethers, Cyclic / Q000737:chemistry / Q000494:pharmacology*; D010716:Phosphatidylinositols / Q000378:metabolism; D010946:Plants, Medicinal / Q000737:chemistry*; D010972:Platelet Activating Factor / Q000494:pharmacology; D010974:Platelet Aggregation / Q000187:drug effects; D010975:Platelet Aggregation Inhibitors / Q000494:pharmacology*; D011817:Rabbits; D013917:Thrombin / Q000494:pharmacology; D013929:Thromboxane B2 / Q000378:metabolism
chemical_list: D001632:Bibenzyls; D004988:Ethers, Cyclic; D010716:Phosphatidylinositols; D010972:Platelet Activating Factor; D010975:Platelet Aggregation Inhibitors; C097634:marchantinquinone; D016718:Arachidonic Acid; D013929:Thromboxane B2; D019796:15-Hydroxy-11 alpha,9 alpha-(epoxymethano)prosta-5,13-dienoic Acid; D000255:Adenosine Triphosphate; D003094:Collagen; D000242:Cyclic AMP; D013917:Thrombin; D006152:Cyclic GMP; D002118:Calcium