Antithrombotic effect of rutaecarpine, an alkaloid isolated from Evodia rutaecarpa, on platelet plug formation in in vivo experiments

In this study, platelet thrombi formation was induced by irradiation of mes enteric venules with filtered light in mice pretreated intravenously with f luorescein sodium. Rutaecarpine (200 mu g/g) significantly prolonged the la tent period of inducing platelet plug formation in mesenteric venules when it was intravenously injected. Rutaecarpine (200 mu g/g) prolonged occlusio n time by approximately 1.5-fold (control 127 +/- 29 vs, taecarpine 188 +/- 23 s). Furthermore, aspirin (250 mu g/g) also showed a similar prolongatio n of the occlusion time in this experiment. On a molar basis, rutaecarpine was approximately twofold more potent than aspirin at prolonging the occlus ion time. Furthermore, rutaecarpine was also effective in reducing the mort ality of ADP-induced acute pulmonary thromboembolism in mice when administe red intravenously at doses of 25 and 50 mu g/g. Intravenous injection of ru taecarpine (50 mu g/g) significantly prolonged the bleeding time by approxi mately 1.5-fold compared with normal saline in the severed mesenteric arter ies of rats. Continuous infusion of rutaecarpine (5 mu g/g/min) also signif icantly increased the bleeding time 1.5-fold, and the bleeding time returne d to baseline within 60 min after cessation of rutaecarpine infusion. These results suggest that rutaecarpine has an effective anti-platelet effect in vivo and that it may be a potential therapeutic agent for arterial thrombo sis, but it must be assessed further for toxicity.