The root of Panax ginseng C. A. Meyer is one of the most popular natural tonics in oriental countries. In this study, we have isolated polysaccharide fraction of Panax ginseng (ginsan) and examined its effect on the function of murine peritoneal macrophages. When macrophages were treated with ginsan, cytotoxic activity against B16 melanoma cells was significantly induced. In addition, the levels of cytokines, including tumor necrosis factor-α (TNF-α), interleukin-1β (IL-1β), IL-6 and lnterferon-γ (IFN-γ) were increased and the production of reactive oxygen/nitrogen components such as nitric oxide (NO) and hydrogen peroxide (H2O2) was enhanced. Moreover, phagocytic activity was induced in ginsan-treated macrophages compared to the control. The expression of CD14 and l-Ab on murine peritoneal macrophages was increased by the treatment with ginsan, while the expression of CD11b was decreased. Taken together, these results suggest that ginsan has an immunopotentiating effects on macrophages and these ...

Ginsan, a polysaccharide extracted from Panax ginseng, has multiple immunomodulatory effects. In this study, we show that pretreatment of ginsan (25 μg/kg) protected mice from lethality induced by Staphylococcus aureus challenge. This survival benefit was associated with enhanced bacterial clearance from circulation, spleen and kidney. The phagocytic activity of macrophages treated with ginsan was significantly enhanced against S. aureus. However, the production of proinflammatory cytokines, such as TNF‐α, IL‐1β, IL‐6, IFN‐γ, IL‐12, and IL‐18, was markedly down‐regulated in ginsan‐treated mice compared with those of control‐infected mice. The expression of Toll‐like receptor (TLR) 2 and the adaptor molecule MyD88, which was greatly increased in septic macrophages, was significantly reduced by ginsan treatment in vitro. Similarly, the expression of phospho‐JNK1/2, phospho‐p38 MAPK, and NF‐κB was decreased in the same culture system. These results illustrate that the antiseptic activity of ginsan can be attributed to enhanced bacterial clearance, and reduced proinflammatory cytokines via the TLR signaling pathway.