White ginseng extract induces immunomodulatory effects via the MKK4-JNK pathway.

Panax ginseng Meyer (white ginseng) is a popular functional food and its biological effects on the human body have been noted for hundreds of years. In the present study, the underlying mechanisms responsible for the immunomodulatory effects of white ginseng extract (WGE) were investigated. WGE increased NO production via upregulation of iNOS expression levels. Mouse cytokine array results also revealed that the expression of 13 cytokines was elevated by WGE treatment in IFN-γ-primed macrophage cells. Although both MKK4-JNK and MEK-ERK signaling pathways were activated after treatment with WGE, only the MKK4-JNK signaling pathway appears to have any significant immunomodulatory significance. Oral administration of WGE for 28 days recovered cyclophosphamide (CY)-induced suppression of the immune system in mice via the MKK4-JNK pathway. Taken together, these findings suggest that the MKK4-JNK signaling pathway is a crucial mechanism of WGE-induced immunomodulation.