Anti-inflammatory effects of chicanine on murine macrophage by down-regulating LPS-induced inflammatory cytokines in IκBα/MAPK/ERK signaling pathways.

Schisandra chinensis Baill is a Chinese traditional medicine with multiple pharmacological activities. In this study, chicanine, one of the major lignan compounds of S. chinesis, was investigated for suppressive effects on lipopolysaccharide (LPS)-induced inflammatory responses in murine macrophages (RAW 264.7 cells). Chicanine was found to have anti-inflammatory properties with the inhibition of nitric oxide (NO) and Prostaglandin E (2) (PGE2) production and nuclear factor-κB (NF-κB) signaling in LPS-stimulated RAW 264.7 cells with no cytotoxic effects. Treatment of RAW 264.7 cells with chicanine down-regulated LPS-induced expression of pro-inflammatory cytokines including TNFα, IL-1β, MCP-1, G-CSF, cyclooxygenase-2 (COX-2) and inducible nitric oxide synthase (iNOS). These inhibitory effects were found with the blockage of p38 mitogen-activated protein kinase (MAPK), extracellular signal-regulated kinases 1 and 2 (ERK 1/2), and also IκB-α phosphorylation. These results indicated that anti-inflammatory actions of chicanine in macrophages involved inhibition of LPS-induced TLR4-IκBα/MAPK/ERK signaling pathways.