title: Antiplatelet action of dehydrokawain derivatives isolated from Alpinia speciosa rhizoma.
abstract: 5,6-Dehydrokawain (DK) and dihydro-5,6-dehydrokawain (DDK) inhibited the aggregation and ATP release of rabbit platelets induced by arachidonic acid and collagen, without affecting those induced by ADP, PAF and thrombin. This inhibition was reversible and in a concentration-dependent manner. The IC50 of DK and DDK on arachidonate-induced platelet aggregation were calculated to be about 10 and 60 micrograms/ml, respectively. Thromboxane B2 formation caused by arachidonic acid was also suppressed by both antiplatelet agents. DK inhibited the intracellular calcium concentration rised by arachidonic acid, but not that by collagen or thrombin. DK also inhibited the secondary, but not the primary aggregation of human platelet-rich plasma induced by ADP and epinephrine. It is concluded that the antiplatelet effect of both DK and DDK is due to the inhibition of thromboxane A2 formation.
authors.affiliation: Pharmacological Institute, College of Medicine, National Taiwan University, Taipei, R.O.C.
authors.forename: C M
authors.initials: CM
authors.lastname: Teng
authors.forename: S Y
authors.initials: SY
authors.lastname: Hsu
authors.forename: C H
authors.initials: CH
authors.lastname: Lin
authors.forename: S M
authors.initials: SM
authors.lastname: Yu
authors.forename: K J
authors.initials: KJ
authors.lastname: Wang
authors.forename: M H
authors.initials: MH
authors.lastname: Lin
authors.forename: C F
authors.initials: CF
authors.lastname: Chen
mesh_terms: D000255:Adenosine Triphosphate / Q000378:metabolism; D000818:Animals; D001792:Blood Platelets / Q000187:drug effects / Q000502:physiology; D004365:Drugs, Chinese Herbal / Q000302:isolation & purification / Q000494:pharmacology*; D006801:Humans; D066298:In Vitro Techniques; D010974:Platelet Aggregation / Q000187:drug effects; D010975:Platelet Aggregation Inhibitors / Q000302:isolation & purification*; D011714:Pyrans / Q000494:pharmacology*; D011753:Pyrones / Q000302:isolation & purification / Q000494:pharmacology*; D011817:Rabbits; D013929:Thromboxane B2 / Q000096:biosynthesis
chemical_list: D004365:Drugs, Chinese Herbal; D010975:Platelet Aggregation Inhibitors; D011714:Pyrans; D011753:Pyrones; C052297:5,6-dehydrokawain; C052296:7,8-dihydro-5,6-dehydrokawain; D013929:Thromboxane B2; D000255:Adenosine Triphosphate