title: Pharmacological profile of epiyangambin: a furofuran lignan with PAF antagonist activity.
abstract: The ability of a furofuran lignan, epiyangambin, to inhibit PAF-induced rabbit platelet aggregation in vitro and thrombocytopenia in rats was investigated. Epiyangambin dose-dependently inhibited PAF-induced platelet aggregation without modifying the amplitude of the maximal response, indicating a competitive antagonism. The IC50 value of epiyangambin for 10(-9) M PAF-induced aggregation was 6.1 x 10(-7) M and the Schild analysis provided a pA2 of 6.91 +/- 0.2 with a slope of 0.98 +/- 0.25 (n = 4) and a pKb of 6.94 +/- 0.19. Epiyangambin had no effect upon the platelet aggregation induced by collagen, thrombin or ADP. The in vivo administration of the lignan at 20 mg/kg significantly inhibited PAF-induced thrombocytopenia in rats. These data indicate that epiyangambin is a potent and selective antagonist of PAF both in vitro and in vivo.
authors.affiliation: Departamento de Fisiologia e Farmacodinâmica, Fundação Oswaldo Cruz, Rio de Janeiro, Brazil.
authors.forename: H C
authors.initials: HC
authors.lastname: Castro-Faria-Neto
authors.forename: M A
authors.initials: MA
authors.lastname: Martins
authors.forename: P M
authors.initials: PM
authors.lastname: Silva
authors.forename: P T
authors.initials: PT
authors.lastname: Bozza
authors.forename: H N
authors.initials: HN
authors.lastname: Cruz
authors.forename: M
authors.initials: M
authors.lastname: de Queiroz-Paulo
authors.forename: M A
authors.initials: MA
authors.lastname: Kaplan
authors.forename: R S
authors.initials: RS
authors.lastname: Cordeiro
mesh_terms: D000818:Animals; D005663:Furans / Q000494:pharmacology*; D017705:Lignans; D008031:Lignin / Q000494:pharmacology*; D008297:Male; D015394:Molecular Structure; D010972:Platelet Activating Factor / Q000037:antagonists & inhibitors*; D010975:Platelet Aggregation Inhibitors / Q000494:pharmacology*; D011817:Rabbits; D051381:Rats; D017208:Rats, Wistar; D013921:Thrombocytopenia / Q000139:chemically induced / Q000188:drug therapy*
chemical_list: D005663:Furans; D017705:Lignans; D010972:Platelet Activating Factor; D010975:Platelet Aggregation Inhibitors; C082827:epiyangambin; D008031:Lignin