Immunomodulatory and anti-inflammatory effects of Phellinus linteus mycelium

BACKGROUND: The present study extensively aimed to evaluate the underlying mechanism of the immunomodulatory and anti-inflammatory effects of Phellinus linteus mycelium (PLM). METHODS: To assess whether PLM influences the production of markers related to inflammation, Lipopolysaccharide (LPS)-stimulated RAW264.7 cells were treated with PLM (50, 100, 200, and 500 μg/mL). Splenocyte, thymus, peritoneal exudate cells (PEC), and peripheral blood mononuclear cells (PBMC) were isolated from the Balb/c mice treated with Korean red ginseng or PLM once a day for 5 weeks. Moreover, all mice except normal mice were stimulated with 10% proteose peptone (PP) treated 3 days before the sacrifice and 2% starch treated 2 days before the sacrifice. Subsequently, the cytotropic substance was evaluated by using flow cytometry analysis and ELISA assay. RESULTS: PLM200 treatment significantly suppressed the production of nitric oxide (NO) and prostaglandin E2 (PGE2) and inhibited the release of proinflammatory cytokines such as interleukin (IL)-6, IL-1β, and tumor necrosis factor (TNF)-α dose-dependently in the LPS-stimulated RAW264.7 cells. PLM200 supplementation showed a significant increase in IL-2, IL-12, and interferon (IFN)-γ production and upregulated the ratio of IFN-γ (T-helper type 1, Th1) to IL-4 (T-helper type 2, Th2) in splenocytes. After PLM200 treatment, the significant elevation of CD4(+)CD25(+), CD4(+)&CD8(+), and CD4(+)CD69(+) treatment were detected in thymus. Moreover, CD4(+) and CD4(+)CD69(+) in PBMC and CD69(+) in PEC were also shown in a significant increase. CONCLUSIONS: Taken together, these results showed an immunomodulatory effect of PLM about an elevated INF-γ/IL4 ratio, as an index of Th1/Th2, as well as the anti-inflammatory effect in the LPS-stimulated RAW264.7 cells. Therefore, our findings demonstrate that PLM possesses immunostimulatory and anti-inflammatory effects.