Inhibition of inducible prostaglandin E2 production and cyclooxygenase-2 expression by curdione from Curcuma zedoaria.

Overproduction of prostaglandins has been considered in mediation of inflammation and carcinogenic process. On this line, the inhibitors of prostaglandin biosynthetic enzyme cyclooxygenase (COX) have played a role of anti-inflammatory and cancer chemopreventive agents. In our continuous efforts to search anti-inflammatory and chemopreventive agents from natural products, bioassay-guided fractionation led to the isolation of curdione from the rhizome of Curcuma zedoaria with the inhibitory effect on the production of prostaglandin E2 in lipopolysaccharide (LPS)-stimulated mouse macrophage RAW 264.7 cells in a concentration-dependent manner (IC50 = 1.1 microM). Mechanistic studies suggest that the suppression of cyclooxygenase-2 (COX-2) mRNA expression is, at least in part, involved in this inhibitory activity of curdione.