Nauclea officinalis inhibits inflammation in LPS-mediated RAW 264.7 macrophages by suppressing the NF-κB signaling pathway

Ethnopharmacological relevance: Nauclea officinalis has been traditionally used in China for the treatment of fever, pneumonia and enteritidis etc. This study aims to investigate effects of N. officinalis on the inflammatory response as well as the possible molecular mechanism in LPS-stimulated RAW 264.7 murine macrophage cells. Materials and methods: Anti-inflammatory activity of N. officinalis (10, 20, 50, and 100 mu g/mL) was investigated by using LPS-induced RAW 264.7 macrophages. The NO production was determined by assaying nitrite in culture supernatants with the Griess reagent. The levels of TNF-alpha, IL-6 and IL-1 beta in culture media were measured with ELISA kits. Real time fluorescence quantitative PCR was detected for mRNA expression of iNOS, TNF-alpha, IL-6 and IL-1 beta. Western blot assay was performed to illustrate the inhibitory effects of N. officinalis on phosphorylation of I kappa B-alpha and NF-kappa B p65. Results: Treatment with N. officinalis (10-100 g/mL) dose-dependently inhibited the production as well as mRNA expression of NO, TNF-alpha, IL-6 and IL-1 beta in RAW 264.7 macrophages. Western blot assay suggested that the mechanism of the anti-inflammatory effect was associated with the inhibition of phosphorylation of I kappa B-alpha and NF-kappa B p65. Conclusions: The results indicated that N. officinalis potentially inhibited the activation of upstream mediator NF-kappa B signaling pathway via suppressing phosphorylation of I kappa B-alpha and NF-kappa B p65 to inhibit LPS-stimulated inflammation. (C) 2016 Elsevier Ireland Ltd. All rights reserved.