Novel highly branched water-soluble heteropolysaccharides as immunopotentiators to inhibit S-180 tumor cell growth in BALB/c mice

The in vitro antitumor activities and in vivo immunomodulatory effects of water-soluble highly branched heteropolysaccharides isolated from Rhizoma panacis Japonici were evaluated by three cell lines and BALB/c mice implanted with Sarcoma 180 (S-180) tumors. The heteropolysaccharides showed potent tumor therapeutic effect by potentiating the animalʹs immune responses including an increase in white blood cell count and lymphocyte number. The heteropolysaccharides also induced apoptosis in the S-180 cells and alleviate the short-term side effect of cisplatin (DDP) to the animal during the treatment period. The bioactivity of the heteropolysaccharides might be due to their unique structures that had an α-(1 → 4)-d-glucan main chain with side chains containing mannose and galactose residues, a spherical chain conformation, as well as high water solubility, all of which facilitated their interaction with the surface receptors of the immune cells.