Ginseng root has been used in
traditional oriental medicine for the enhancement of immune system function. The immunostimulatory effects of ginseng berry
polysaccharides, however, remain unclear. Effects of
polysaccharides from ginseng berry on the activation of natural killer (NK) cells and inhibition of
tumors are reported. A crude
polysaccharide was isolated from ginseng berry as a ginseng berry
polysaccharide portion (GBPP) and was further fractionated using gel filtration chromatography to obtain the three
polysaccharide fractions GBPP-I, -II and -III. GBPP-I consisted of mainly
galactose (46.9%) and
arabinose (27.5%). GBPP-I showed a high dose-dependent anticomplementary activity. Stimulation of murine peritoneal macrophages by GBPP-I showed the greatest enhancement of
interleukin (IL)-6 and
IL-12 and
tumor necrosis factor (TNF)- α production. In addition, an ex vivo assay of natural killer (NK) cell activity showed that oral ( p.o.) administration of GBPP-I significantly increased NK cell cytotoxicity in YAC-1
tumor cells and production of
granzyme B. Prophylactic intravenous ( i.v.) and p.o. administration of GBPP-I significantly and dose-dependently inhibited lung metastatic activity in B16BL6
melanoma cells. Depletion of NK cells after injection of rabbit anti-
asialo GM1 partially abolished the inhibitory effect of GBPP-I on lung
metastasis, indicating that NK cells play an important role in anticancer effects. GBPP-I exerts a strong immune-enhancing activity and can prevent
cancer metastasis through activation of NK cells and other immune-related cells.