Ginsenoside Rc from Panax ginseng exerts anti-inflammatory activity by targeting TANK-binding kinase 1/interferon regulatory factor-3 and p38/ATF-2

Background: Ginsenoside Rc (G-Rc) is one of the major protopanaxadiol-type saponins isolated from Panax ginseng, a well-known medicinal herb with many beneficial properties including anticancer, antiinflammatory, antiobesity, and antidiabetic effects. In this study, we investigated the effects of G-Rc on inflammatory responses in vitro and examined the mechanisms of these effects. Methods: The in vitro inflammation system used lipopolysaccharide-treated macrophages, tumor necrosis factor-a/interferon-g-treated synovial cells, and HEK293 cells transfected with various inducers of inflammation. Results: G-Rc significantly inhibited the expression of macrophage-derived cytokines, such as tumor necrosis factor-a and interleukin-1b. G-Rc also markedly suppressed the activation of TANK-binding kinase 1/IkB kinase ε/interferon regulatory factor-3 and p38/ATF-2 signaling in activated RAW264.7 macrophages, human synovial cells, and HEK293 cells. Conclusion: G-Rc exerts its anti-inflammatory actions by suppressing TANK-binding kinase 1/IkB kinase ε/interferon regulatory factor-3 and p38/ATF-2 signaling.