OBJECTIVEThis study aimed to evaluate whether Hwangryunhaedoktang (HHT), a herbal compound, has an inhibitory effect on lipopolysaccharide (LPS)-induced inflammation in RAW264.7 macrophages.

METHODSThe effects of HHT were evaluated by confirming nitric oxide (NO) production and expression of inducible NO synthase (iNOS) and mitogen-activated protein kinases (MAPKs) in LPS-stimulated RAW264.7 macrophages via the Griess assay, Western blotting, and real-time reverse transcription quantitative polymerase chain reaction. Western blot analyses and luciferase assays were used to evaluate whether HHT has an effect on the phosphorylation and translocation of nuclear factor-κB (NF-κB). The secretion and expression of tumor necrosis factor-α (TNF-α) and interleukin-6 (IL-6) were determined via enzyme-linked immunosorbent assay and Western blot analyses.

RESULTSHHT suppressed LPS-induced NO production and expression of iNOS in a dose-dependent manner. Additionally, MAPKs activation was also attenuated via inhibition of phosphorylation of extracellular signal-regulated kinases 1/2, c-Jun N-terminal kinase and p38 which were related to inflammatory pathway. Furthermore, HHT also effectively attenuated NF-κB activation and its translocation to the nucleus, a process that is closely linked to inflammation. LPS normally induced the expression of inflammatory cytokines such as TNF-α and IL-6, but the secretion and expression of TNF-α and IL-6 were significantly attenuated by pretreating the cells with HHT.

CONCLUSIONHHT suppressed LPS-induced NO production by blocking the activation of NF-κB and MAPK signaling pathways in RAW264.7 macrophages. Furthermore, HHT may have an anti-inflammatory effect by suppressing the LPS-induced secretion of TNF-α and IL-6. Therefore, the traditional herbal formula HHT might be a useful potential therapeutic agent for inflammation.