Anti-tumor activity of the regenerated triple-helical polysaccharide from Dictyophora indusiata.

A triple helical polysaccharide (PD3) was isolated from Dictyophora indusiata. After denaturation in dilute NaOH solution (0.3 M) and renaturation by sequential dialysis, regenerated polysaccharide (RPD3) was obtained. The physico-chemical properties of RPD3 including intrinsic viscosity [η], molecular weight (Mw) and optical rotation were similar to those of PD3, which suggested that RPD3 also had a triple helical structure after denaturation-renaturation. However, different intrinsic viscosity dependence on the concentration of NaOH solution was noted in PD3 and RPD3, which indicated that RPD3 had lower chain tightness compared with PD3. The anti-tumor activity of this polysaccharide after denaturation-renaturation treatment was further investigated. Both PD3 and RPD3 showed no direct cytotoxicity against S-180 cells in vitro but behaved anti-tumor activity in vivo. Meanwhile, RPD3 in high-dose group showed much higher anti-tumor activity than that of PD3, suggesting that the denaturation-renaturation treatment improved the bioactivity of the polysaccharide from D. indusiata.