Sesquiterpenes from <i>Curcuma wenyujin</i> with their inhibitory activities on nitric oxide production in RAW 264.7 cells

<p>One new sesquiterpene, 7α,11-epoxy-6α-hydroxy-carabrane-4,8-dione, along with 10 known ones were isolated from the essential oil of <i>Curcuma wenyujin</i> Y.H. Chen et C. Ling. Their structures were established based on extensive spectroscopic analysis. The absolute configuration of compound <b>1</b> was determined by the CD analysis of the insitu formed [Rh₂(OCOCF₃)₄] complex, and the CD data analysis based on the octane rule of cyclohexanone. The inhibitory effects of these sesquiterpenes on nitric oxide production in lipopolysaccharide-activated macrophages were also evaluated. Furthermore, the biosynthesis pathway of the isolated compounds was proposed.