Isolation, characterization and immunological activity of a polysaccharide from the fruit bodies of an edible mushroom, Sarcodon aspratus (Berk.) S. Ito.

A water-soluble polysaccharide (HCP) with a molecular mass of 6.7 × 105 Da determined by high performance size-exclusion chromatography (HPSEC), was isolated from the fruit bodies of Sarcodon aspratus (Berk.) S. Ito., an edible mushroom. HCP was elucidated as a liner glucan with a backbone structure of (1 → 6)-linked-α-d-glucopyranosyl residues by interpretation of the composition analysis, methylation analysis, periodate oxidation experiment, FT-IR, and NMR spectroscopy. Immunological activity evaluation using H3-thymidine incorporation method revealed that HCP could significantly stimulate the proliferation of the cultured mice spleen lymphocyte in a dose-dependent manner. HCP might be a potential immunomodulator which can be used against pathogens and tumors in health-care food or medicine. This is the first report on the detailed structure elucidation of the polysaccharide from S. aspratus.