title: Novel antiplatelet naphthalene from Rhamnus nakaharai.
abstract: A new naphthalene derivative, isotorachrysone [1], was isolated from the stem bark of Rhamnus nakaharai along with several known compounds. The antiplatelet effects of isotorachrysone [1], isotorachrysone peracetate [2], 6-methoxysorigenin [3], quercetin 3-O-methyl ether [4], and quercetin 3-O-methyl ether peracetate [5] were studied using washed rabbit platelets. Of the compounds tested, 1, 2, 4, and 5 showed potent antiplatelet effects on arachidonic acid (AA-) and collagen-induced platelet aggregation. Compound 5 also showed potent antiplatelet effects on platelet-activating factor-(PAF-) induced platelet aggregation. Isotorachrysone [1] and its peracetate [2] were also studied for antiplatelet activity in human platelet-rich plasma (PRP) and both showed potent inhibition of the secondary aggregation induced by epinephrine. The antiplatelet effects of 1 and 2 are due partially to an inhibitory effect on thromboxane formation.
authors.affiliation: National Taiwan University, Taipei, Republic of China.
authors.forename: C N
authors.initials: CN
authors.lastname: Lin
authors.forename: C M
authors.initials: CM
authors.lastname: Lu
authors.forename: H C
authors.initials: HC
authors.lastname: Lin
authors.forename: F N
authors.initials: FN
authors.lastname: Ko
authors.forename: C M
authors.initials: CM
authors.lastname: Teng
mesh_terms: D000818:Animals; D003094:Collagen / Q000494:pharmacology; D066298:In Vitro Techniques; D009682:Magnetic Resonance Spectroscopy; D009281:Naphthalenes / Q000302:isolation & purification* / Q000494:pharmacology*; D018547:Plant Stems / Q000737:chemistry; D010946:Plants, Medicinal / Q000737:chemistry*; D010974:Platelet Aggregation / Q000187:drug effects; D010975:Platelet Aggregation Inhibitors / Q000302:isolation & purification* / Q000494:pharmacology*; D010976:Platelet Count / Q000187:drug effects; D011817:Rabbits; D013624:Taiwan
chemical_list: D009281:Naphthalenes; D010975:Platelet Aggregation Inhibitors; D003094:Collagen