Anti-inflammatory effect of Inonotus obliquus extracts in lipopolysaccharide-induced mouse peritoneal macrophage

Abstract

Macrophages play a vital role in the innate immune system involving defensive cytokines such as TNF (tumor necrosis factor)-α and nitric oxide (NO). Therefore, we try to elucidate the anti-inflammatory activity of Chaga mushroom (Inonotus Obliquus, IO) in murine macrophages. Raw 264.7 cells and peritoneal macrophages of mice were cultured with or without LPS/LPS + IFN-γ in the presence of IO aqueous extracts (IOE 0.2, 2, 20, 100 μg/mL) for 24 hr and 48 hr, respectively. Exposure of IOE caused the decrease of NO production and increase of TNF-α production in dose-dependent manner in activated peritoneal macrophage in vitro. To further investigate anti-inflammatory effects of IO ex vivo, we orally administrated capsaicin (PC, 3 mg/kg/day) and IOE (100, 200, 400 mg/kg/day) for 4 consecutive days to C57BL/6 mice (7~9 weeks old, female), then observed the NO secretion and cytokine (TNF-α) production of LPS/LPS + INF-γ-stimulated peritoneal macrophages. IOE inhibits NO secretion in dose-dependent manner both ex vivo and in vitro and increases the production of TNF- α in vitro. In addition, we found that IOE possessed suppressive effects of LPS-stimulated TNF-α, IL-1β, COX-2, as well as iNOS expressions in Raw 264.7 cells. These findings indicate that IOE suppress not only the LPS-induced NO overproduction of murine peritoneal macrophages, but also iNOS, COX-2, TNF-α, and IL-1β overexpression of LPS-induced Raw 264.7 cells. Consequently, our results suggest that IO may have the anti-inflammatory effects via suppression of the inflammatory cytokines and mediators, and be useful for the treatment of inflammatory diseases.