In vivo radioprotective effect of Panax ginseng C.A.!Meyer and identification of active ginsenosides

This study evaluated the effect of water extracts of Panax ginseng C.A. Meyer (PG), panaxadiol (PD), panaxatriol (PT), ginsenoside Rb-1, Rb-2, Rc, Rd, Re and Rg(1) on jejunal crypt survival, endogenous spleen colony formation and apoptosis in jejunal crypt cells in gamma-irradiated mice. Jejunal crypts were protected by pretreatment with PG, Rc and Rd. Administration of PG, PD, Rd and Re prior to irradiation resulted in an increase in the formation of endogenous spleen colonies. The frequency of radiation-induced apoptosis in intestinal crypt cells was also reduced by pretreatment with PG, PD, Rb-2, Rc, Rd, Re and Rg(1). In experiments on the effects of the individual ginsenosides, the rank order of activity was Rc > Rd > Rg(1) > Rb-2 > Re > Rb-1 on intestinal crypt survival assay, Re > Rb-2 > Rd > Rg(1) > Rb-1 > Rc on the spleen colony formation assay, and Rg(1) > Re > Rd > Rc > Rb-2 > Rb-1 on inhibiting the death of cells caused by apoptosis. The results indicated that Rc, Rd and Re may have a major radioprotective effect in mice irradiated with high and low doses of radiation. When the same experiments were performed using PD and PT, it was observed that most of the inhibitory effects came from PD rather than PT. Copyright (c) 2006 John Wiley & Sons, Ltd.