title: A platelet phospholipase inhibitor from the medicinal herb feverfew (Tanacetum parthenium).
abstract: Feverfew has been used since antiquity to treat fevers and other inflammatory conditions. Feverfew extracts were found to inhibit ADP, thrombin, or collagen-induced aggregation of human platelets, but significantly, did not affect aggregation induced by arachidonic acid. Synthesis of thromboxane B2 from exogenous 14C-arachidonic acid was also not inhibited. Washed platelets prelabelled with 14C-AA responded normally to thrombin by releasing 14C-TXB2. This was completely blocked by feverfew. A purified platelet phospholipase A2 was inhibited by the material with an I50 of 0.1 antiplatelet units. The pharmacological properties of feverfew may thus be due to an inhibitor of cellular phospholipases, which prevents release of arachidonic acid in response to appropriate physiological stimuli.
mesh_terms: D019377:12-Hydroxy-5,8,10,14-eicosatetraenoic Acid; D000244:Adenosine Diphosphate / Q000494:pharmacology; D016718:Arachidonic Acid; D001095:Arachidonic Acids / Q000097:blood; D001792:Blood Platelets / Q000201:enzymology*; D003094:Collagen / Q000494:pharmacology; D005231:Fatty Acids, Unsaturated / Q000097:blood; D006801:Humans; D006880:Hydroxy Acids / Q000097:blood; D066298:In Vitro Techniques; D019684:Magnoliopsida; D010740:Phospholipases / Q000037:antagonists & inhibitors* / Q000097:blood; D010936:Plant Extracts / Q000494:pharmacology*; D010946:Plants, Medicinal; D012717:Sesquiterpenes / Q000494:pharmacology*; D020903:Tanacetum parthenium; D013917:Thrombin / Q000494:pharmacology; D013929:Thromboxane B2 / Q000097:blood
chemical_list: D001095:Arachidonic Acids; D005231:Fatty Acids, Unsaturated; D006880:Hydroxy Acids; D010936:Plant Extracts; D012717:Sesquiterpenes; D016718:Arachidonic Acid; C008033:12-hydroxy-5,8,10-heptadecatrienoic acid; D013929:Thromboxane B2; D019377:12-Hydroxy-5,8,10,14-eicosatetraenoic Acid; D000244:Adenosine Diphosphate; D003094:Collagen; D010740:Phospholipases; D013917:Thrombin