Anti-inflammatory activity of atractylenolide III through inhibition of nuclear factor-κB and mitogen-activated protein kinase pathways in mouse macrophages

To elucidate the anti-inflammatory mechanisms involved, we investigated the effects of atractylenolide III (ATL-III) on cytokine expression, extracellular signal-regulated kinases 1 and 2 (ERK1/2), p38 mitogen-activated protein kinase (p38), C-Jun-N-terminal protein kinase1/2 (JNK1/2) and nuclear factor-B (NF-B) pathways in lipopolysaccharide (LPS)-induced RAW264.7 mouse macrophages. Macrophages were incubated with various concentrations (0, 25, 50, 100 M) of ATL-III and/or LPS (1 g/mL) for 24h. The production of nitric oxide (NO) was determined by the Greiss reagent. The production of tumor necrosis factor alpha (TNF-), prostaglandin E2 (PGE2) and interleukin 6 (IL-6) was determined by enzyme-linked immunosorbent assay (ELISA). Furthermore, macrophages were treated with ATL-III (0, 25, 100 M) for 1h and then stimulated by LPS. NF-B, p38, JNK1/2 and ERK1/2 were determined by western blotting. We found ATL-III showed no inhibitory effect on cell proliferation at concentrations ranging from 1 M to 100 M. In addition, ATL-III decreased the release of NO, TNF-, PGE2 and IL-6 in a dose-dependent manner and showed statistically significant at concentrations of 50 M and 100 M as well as cyclooxygenase-2 (COX-2) expression. Furthermore, ATL-III suppressed the transcriptional activity of NF-B. ATL-III also inhibited the activation of ERK1/2, p38 and JNK1/2 in LPS-treated macrophages and showed statistically significant at concentrations of 25 M and 100 M. These data suggest that ATL-III shows an anti-inflammatory effect by suppressing the release of NO, PGE2, TNF- and IL-6 related to the NF-B- and MAPK-signaling pathways.