Methyl-1-hydroxy-2-naphthoate, a novel naphthol derivative, inhibits lipopolysaccharide-induced inflammatory response in macrophages via suppression of NF-κB, JNK and p38 MAPK pathways.

OBJECTIVE AND DESIGN: The anti-inflammatory effect of methyl-1-hydroxy-2-naphthoate (MHNA), a novel naphthol derivative, was evaluated in the lipopolysaccharide (LPS)-induced inflammatory response in murine macrophages.

MATERIALS AND METHODS: The release of nitric oxide (NO), interleukin-1beta (IL-1β) and interleukin-6 (IL-6) were detected by the Griess reagent and ELISA methods. The protein expressions of inducible NO synthase (iNOS) and cyclooxygenase-2 (COX-2) were examined by Western blotting. The mRNA expressions of IL-1β, IL-6, iNOS and COX-2 were determined by real-time PCR. Activation of mitogen-activated protein kinases (MAPKs) and nuclear factor kappa B (NF-κB) pathways were detected by Western blotting, reporter gene assay and electrophoretic mobility shift assay.

RESULTS: MHNA significantly inhibited the release of NO, IL-1β and IL-6 as well as the protein expression of iNOS and COX-2 in LPS-stimulated macrophages. It also inhibited the mRNA expression of iNOS, COX-2, IL-1β and IL-6. Further studies indicated that MHNA inhibited LPS-induced increases in NF-κB DNA-binding activity and NF-κB transcriptional activity as well as IκB-α degradation and NF-κB translocation in a dose-dependent manner. Meanwhile, the activation of p38 MAPK and c-Jun N-terminal kinases (JNK) induced by LPS were decreased by MHNA.

CONCLUSIONS: MHNA inhibits the LPS-induced inflammatory response in murine macrophages via suppression of NF-κB and MAPKs signaling pathways activation.