Inhibition of LPS-induced NO production and NF-kappaB activation by a sesquiterpene from Saussurea lappa.

To elucidate the molecular mechanisms for the suppression of LPS-induced nitric oxide (NO) production by a dehydrocostus lactone (DL) from Saussurea lappa, we examined the preventive effect of this compound on NF-kappaB activation in LPS-treated RAW 264.7 macrophages and U937 human monocytic cells. The results suggest that the suppression of NO production is mediated by the inhibitory action on the i-NOS gene expression through the inactivation of NF-kappaB and this sesquiterpene lactone can act as a pharmacological inhibitor of the NF-kappaB activation.