Nitric oxide is involved in the immunomodulating activities of acidic polysaccharide from Panax ginseng

The effects of an acidic polysaccharide isolated from the ethanol-insoluble and water-soluble fraction of Panax ginseng C. A. Meyer on immunomodulatin g activities were investigated. A high output nitric oxide synthase (iNOS) was shown in female BALB/c mice administered intraperitoneally with the aci dic polysaccharide from ginseng. Newly synthesized iNOS protein was also ob served in peritoneal macrophages cultured with interferon-gamma and the aci dic polysaccharide. Spleen cells from acidic polysaccharide-treated mice di d not proliferate in response to concanavalin A, but restored the responsiv eness by the cotreatment of N-G-monomethyl-(L)-arginine (NMMA) with concana valin A. The treatment of mice with aminoguanidine, a specific iNOS inhibit or, alleviated the acidic polysaccharide-induced suppression of antibody re sponse to sheep red blood cells. Present results suggest that the immunomod ulating activities of the acidic polysaccharide were mediated by the produc tion of nitric oxide.