Structural determination and antitumor activities of a water-soluble polysaccharide from Mortierella hepiali

A water-soluble polysaccharide (MHP-1) isolated from cultured Mortierella hepiali was obtained by hot-water extraction, DEAE-cellulose 52 anion-exchange, and Sephadex G-25 gel permeation chromatography. Its structural characteristics were investigated by PMP pre-column derivation, partial hydrolysis with acid, methylation analysis, as well as FTIR and NMR spectroscopy. Data revealed that MHP-1 possessed a backbone consisting of the repeating unit→2)-β-d-Manp-(1, 6)-β-d-Glcp-(1→and 3)-β-d-Manp-(1→, branching at O-4 of→2)-β-d-Manp-(1, and terminated with β-d-Manp. The antitumor effects of MHP-1 on H22 tumor-bearing mice were studied. Results showed that MHP-1 significantly inhibited the growth of implanted H22 tumors in mice in vivo, but not on H22, A549, and Hep-G2 cells in vitro. Serum and spleen cells were separated to evaluate the concentrations of TNF-α by ELISA kit. The release of TNF-α was markedly induced by MHP-1 in a dose-dependent manner.