Inhibition by glaucocalyxin A of aggregation of rabbit platelets induced by ADP, arachidonic acid and platelet-activating factor, and inhibition of [3H]-PAF binding.
Glaucocalyxin A is a new diterpenoid isolated from the ethereal extract of the leaves of Rabdosia japonica (Burm f) Hara var glaucocalyx (Maxim) Hara (Labiatae) collected in the northeastern China. When it was incubated with washed rabbit platelets, glaucocalyxin A inhibited ADP- or arachidonic acid-induced platelet aggregation with IC50 values of 4.4 mumol/l, 14.1 mumol/l respectively. Glaucocalyxin A also inhibited PAF-induced aggregation of rabbit platelets which were refractory to ADP and arachidonic acid with an IC50 value of 13.7 mumol/l. Analysis of [3H]-PAF binding showed that glaucocalyxin A prevented [3H]-PAF binding to intact washed rabbit platelets with an IC50 value of 8.16 mumol/l, which was consistent with its inhibition of PAF-induced platelet aggregation.
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Department of Pharmacology, College of Pharmacy, Second Military Medical University, Shanghai, P.R., China.
Kun
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D000244:Adenosine Diphosphate / Q000494:pharmacology; D000818:Animals; D016718:Arachidonic Acid / Q000494:pharmacology; D001792:Blood Platelets / Q000187:drug effects / Q000378:metabolism; D045786:Diterpenes, Kaurane; D004365:Drugs, Chinese Herbal / Q000737:chemistry / Q000494:pharmacology*; D005260:Female; D005995:Glyceryl Ethers / Q000494:pharmacology; D066298:In Vitro Techniques; D007700:Kinetics; D008297:Male; D015394:Molecular Structure; D010972:Platelet Activating Factor / Q000378:metabolism / Q000494:pharmacology; D010974:Platelet Aggregation / Q000187:drug effects*; D010975:Platelet Aggregation Inhibitors / Q000494:pharmacology*; D011817:Rabbits; D013844:Thiazoles / Q000494:pharmacology
D045786:Diterpenes, Kaurane; D004365:Drugs, Chinese Herbal; D005995:Glyceryl Ethers; D010972:Platelet Activating Factor; D010975:Platelet Aggregation Inhibitors; D013844:Thiazoles; C053235:Ro 19-3704; D016718:Arachidonic Acid; D000244:Adenosine Diphosphate; C055124:glaucocalyxin A