Anti-inflammatory effects of Ciwujianoside C3, extracted from the leaves of Acanthopanax henryi (Oliv.) Harms, on LPS-stimulated RAW 264.7 cells

Abstract

The present study aimed to investigate the unknown mechanisms underlying the anti-inflammatory activity of Ciwujianoside C3 (CJS C3), extracted from the leaves of Acanthopanax henryi Harms, on lipopolysaccharide (LPS)-stimulated RAW 264.7 cells. Cells were treated with CJS C3 for 1 h prior to the addition of 200 ng/ml LPS. Cell viability was measured using the MTS assay. Nitric oxide levels were determined by Griess assay. Proinflammatory cytokine production was measured by enzyme-linked immunosorbent assay. The expression levels of cyclooxygenase (COX)-2, inducible nitric oxide synthase (iNOS), and mitogen-activated protein kinases (MAPKs) were investigated by western blotting, reverse transcription (RT)-polymerase chain reaction (PCR) and RT-quantitative PCR. Nuclear factor (NF)-κB/p65 localization, and interaction of the TLR4 receptor with LPS was examined by immunofluorescence assay. The results indicated that CJS C3 exhibited no cytotoxicity at the measured concentrations. Treatment with CJS C3 inhibited NO production, proinflammatory cytokine levels, including interleukin (IL)-6, tumor necrosis factor (TNF)-α, and prostaglandin E2 (PGE2), and protein and mRNA expression levels of iNOS and COX-2. Furthermore, CJS C3 suppressed phosphorylation of extracellular signal-regulated kinases and c-jun N-terminal kinases. It was also able to suppress activation of NF-κB via inhibition of the TLR4 signaling pathway. These results suggested that CJS C3 exerts inhibitory effects on LPS-induced PGE2, NO, IL-6 and TNF-α production. In addition, iNOS and COX-2 expression was decreased in murine macrophages. These inhibitory effects may be achieved via suppression of MAPKs and NF-κB phosphorylation following inhibition of the TLR4 signaling pathway.