Eugenol suppresses inducible cyclooxygenase-2(COX-2) expressionin lipopolysaccharide-stimulated mouse macrophage cells.

Based on the potential inhibitors of cyclooxygenase-2 (COX-2) as anti-inflammatory or cancer chemopreventive agents, we have evaluated the active principles of COX-2 inhibition from natural products. The methanol extract of the cortex of Eugenia caryoplyllata (Myrtaceae) showed the potent inhibition of prostaglandin E$_2$(PGE$_2$) production in lipopolysaccharide (LPS)-activated RAW 264.7 cells (98.3% inhibition at the test concentration of 10 $\mu\textrm{g}$/$m\ell$) Further, hexane-soluble layer was the most active partition compared to ethyl acetate, n-butanol, and water -soluble parts. By bioassay-guided fractionation of hexane-soluble layer, eugenol was isolated and exhibited a significant suppression of PGE$_2$ production (IC$\_$50/=0.06$\mu\textrm{g}$/$m\ell$). In addition, eugenol suppressed the COX-2 gene expression in LPS-stimulated mouse macrop-hage cells. Therfore, eugenol might be a plausible lead candidate for further developing the COX-2 inhibitor as an anti-inflammatory or cancer chemopreventive agent.