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

► Highly branched water-soluble heteropolysaccharides (WSHP) were isolated from Rhizoma panacis Japonici. ► WSHP were α-(1 → 4)-d-glucan with side chain residues of mannose and galactose in spherical chain conformation. ► WSHP inhibited the growth of Sarcoma 180 tumors implanted in BALB/c mice. ► The antitumor effect of WSHP was mediated by potentiation of immune cells and induction of apoptosis in the tumor cells. ► WSHP alleviated the short-term side effect of the antitumor drug cisplatin during the treatment period.