A new class of COX-2 inhibitor, rutaecarpine from Evodia rutaecarpa

Abstract.

Objective and Design: We investigated the effect of a new class of COX-2 inhibitor, rutaecarpine, on the production of PGD₂ in bone marrow derived mast cells (BMMC) and PGE₂ in COX-2 transfected HEK293 cells. Inflammation was induced by γ-carrageenan in male Splague-Dawley (SD) rats.¶Material: Rutaecarpine (8,13-Dihydroindolo[2',3':3,4]pyridol[2,1-b]quinazolin-5(7H)-one) was isolated from the fruits of Evodia rutaecarpa. BMMC were cultured with WEHI-3 conditioned medium. c-Kit ligand and IL-10 were obtained by their expression in baculovirus.¶Methods: The generation of PGD₂ and PGE₂ were determined by their assay kit. COX-1 and COX-2 protein and mRNA expression was determined by BMMC in the presence of KL, LPS and IL-10.¶Treatment: Rutaecarpine and indomethacin dissolved in 0.1% carboxymethyl cellulose was administered intraperitoneally and, 1h later, γ-carrageenan solution was injected to right hind paw of rats. Paw volumes were measured using plethysmometer 5h after γ-carrageenan injection.¶Results: Rutaecarpine inhibited COX-2 and COX-1 dependent phases of PGD₂ generation in BMMC in a concentration-dependent manner with an IC₅₀ of 0.28 μM and 8.7 μM, respectively. It inhibited COX-2-dependent conversion of exogenous arachidonic acid to PGE2 in a dose-dependent manner by the COX-2-transfected HEK293 cells. However, rutaecarpine inhibited neither PLA₂ and COX-1 activity nor COX-2 protein and mRNA expression up to the concentration of 30 μM in BMMC, indicating that rutaecarpine directly inhibited COX-2 activity. Furthermore, rutaecarpine showed in vivo anti-inflammatory activity on rat γ-carrageenan induced paw edema by intraperitoneal administration.¶Conclusion: Anti-inflammatory activity of Evodia rutaecarpa could be attributed at least in part by inhibition of COS-2.