Artemisolide from Artemisia asiatica: Nuclear Inhibitor Suppressing Prostaglandin and Nitric Oxide Production in Macrophages

Aerial parts of Artemisia asiatica (Compositae) have been traditionally used as an oriental medicine for the treatment of inflammatory and ulcerogenic diseases. In the present study, artemisolide was isolated as a nuclear factor $(NF)-{\kappa}B$ inhibitor from A. asiatica by activity-guided fractionation. Artemisolide inhibited $NF-{\kappa}B$ transcriptional activity in lipopolysaccharide (LPS)-stimulated macrophages RAW 264.7 with an $IC_{50}$ value of $5.8\;{\mu}M$. The compound was also effective in blocking $NF-{\kappa}B$ transcriptional activities elicited by the expression vector encoding the $NF-{\kappa}B$ p65 or p50 subunits bypassing the inhibitory kB degradation signaling $NF-{\kappa}B$ activation. The macrophages markedly increased their $PGE_2$ and NO production upon exposure to LPS alone. Artemisolide inhibited LPS-induced $PGE_2$ and NO production with $IC_{50}$ values of $8.7\;{\mu}M$ and $6.4\;{\mu}M$, respectively, but also suppressed LPS-induced synthesis of cyclooxygenase (COX)-2 or inducible NO synthase (iNOS). Taken together, artemisolide is a $NF-{\kappa}B$ inhibitor that attenuates LPS-induced production of $PGE_2$ or NO via down-regulation of COX-2 or iNOS expression in macrophages RAW 264.7. Therefore, artemisolide could represent and provide the anti-inflammatory principle associated with the traditional medicine, A. asiatica.