Acacia Honey Exerts Anti-Inflammatory Activity through Inhibition of NF-κB and MAPK/ATF2 Signaling Pathway in LPS-Stimulated RAW264.7 Cells

Honey used as conventional medicine has various pharmacological properties. In the honey and anti-inflammatory effect, Gelam honey and Manuka honey has been reported to exert anti-inflammatory activity. However, the anti-inflammatory effect and potential mechanisms of acacia honey (AH) are not well understood. In this study, we investigated anti-inflammatory activity and mechanism of action of AH in LPS-stimulated RAW264.7 cells. AH attenuated NO production through inhibition of iNOS expression in LPS-stimulated RAW264.7 cells. AH also decreased the expressions of $IL-1{\beta}$, IL-6 and $TNF-{\alpha}$ as pro-inflammatory cytokines, and MCP-1 expression as a pro-inflammatory chemokine. In the elucidation of the molecular mechanisms, AH decreased LPS-mediated $I{\kappa}B-{\alpha}$ degradation and subsequent nuclear accumulation of p65, which resulted in the inhibition of $NF-{\kappa}B$ activation in RAW264.7 cells. AH dose-dependently suppressed LPS-mediated phosphorylation of ERK1/2 and p38 in RAW264.7 cells. In addition, AH significantly inhibited ATF2 phosphorylation and nuclear accumulation of ATF2 in LPS-stimulated RAW264.7 cells. These results suggest that AH has an anti-inflammatory effect, inhibiting the production of pro-inflammatory mediators such as NO, iNOS, $TNF-{\alpha}$, IL-6, $IL-1{\beta}$ and MCP-1 via interruption of the $NF-{\kappa}B$ and MAPK/ATF2 signaling pathways.