Eutigoside C, a compound isolated from the leaves of Eurya emarginata, is thought to be an active anti-inflammatory compound which operates through an unknown mechanism. In the present study we investigated the molecular mechanisms of eutigoside C activity in lipopolysacchardide (LPS)-stimulated murine macrophage RAW 264.7 cells. Treatment with eutigoside C inhibited LPS-stimulated production of nitric oxide (NO), prostaglandin E(2) (PGE(2)) and interleukin-6 (IL-6). To further elucidate the mechanism of this inhibitory effect of eutigoside C, we studied LPS-induced nuclear factor (NF)-kappaB activation and mitogen-activated protein (MAP) kinase phosphorylation. Eutigoside C suppressed NF-kappaB DNA binding activity, interfering with nuclear translocation of NF-kappaB. Eutigoside C suppressed the phosphorylation of three MAP kinases (ERK1/2, JNK and p38). These results suggest that eutigoside C inhibits the production of inflammatory mediators (NO, PGE(2) and interleukin-6) by suppressing the activation and translocation of NF-kappaB and the phosphorylation of MAP kinases (ERK1/2, JNK and p38) in LPS-stimulated murine macrophage RAW 264.7 cells.