Ganoderma lucidum Inhibits LPS- and IFN-γ-Stimulated Nitric Oxide Production and Inflammatory Response in RAW264.7 Macrophage
Background : Ganoderma lucidum is a non-toxic, medicinal mushroom, which is known to possess anti-inflammatory and immunomodulating activities. However, the effects and mechanism of action of Ganoderma lucidum on lipopolysaccharide (LPS) and interferon-gamma (IFN-γ)-induced nitric oxide (NO) production and its-related cytokine expression are not yet fully understood. This study aimed to evaluate the effect of Ganoderma lucidum on NO production and NO-mediated pro-inflammatory cytokine expression in LPS/IFN-γ-induced RAW 264.7 macrophage-like cells. Methods and Results : The results showed that Ganoderma lucidum inhibited inducible NO synthase (iNOS) expression of RAW 264.7 macrophage-like cells at non-cytotoxic concentrations probably through the reduction of reactive oxygen species (ROS) production. After pre-treatment of cells with non-toxic doses of Ganoderma lucidum; NO production was significantly decreased. Moreover, Ganoderma lucidum treatment suppressed LPS/IFN-γ -stimulated pro-inflammatory cytokine secretion, including interleukin-1β and interleukin-6, in a dose-dependent manner. Conclusion : Taken together, these results indicate that the anti-inflammatory activation of Ganoderma lucidum in LPS/IFN-γ-stimulated macrophages might be due to abrogation of NO-dependent cytokine release by impairment of iNOS expression via ROS generation.