Evaluation of antipruritic effects of red ginseng and its ingredients in mice.

The anti-pruritic effect of red ginseng (the steamed root of Panax ginseng C.A. Meyer, Araliaceae), a traditional medicine in Asian countries, was investigated in mouse scratching behavior models induced by either compound 48/80 or histamine. Red ginseng and its saponin fraction, but not its polysaccharide fraction, showed an anti-pruritic effect. Representative constituents in the saponin fraction, ginsenosides Rg3 and Rh2, inhibited scratching behavior and vascular permeability. These ginsenosides also inhibited the expression of TNF-alpha and IL-4 induced by IgE-antigen complex in RBL-2H3 cells, as well as acetic acid-induced writhing in mice. These results suggest that red ginseng and its ingredients, ginsenosides Rg3 and Rh2, may inhibit scratching behavior by inhibiting IL-4 and TNF-alpha expression, promoting membrane stability, and inhibiting Ca (++) influx.