Objective  Chemical structure and in vitro immunological activity of the water soluble polysaccharides from Sparassis latifolia were studied .

  Method  The lyophilized powder of S. latifolia fruiting bodies was extracted by hot water to obtain polysaccharides SCG-D. From the extract, the SCG-N and SCG-A fractions were isolated by the DEAE-Sepharose Fast Flow ion exchange chromatography. The structure of SCG-A was analyzed using HPSEC, monosaccharide composition analysis, FT-IR, and NMR. The in vitro immunological activities of the extract and the fractions were determined by a test on rat spleen lymphocytes.

  Result  SCG-D was found active in promoting the lymphocyte proliferation. SCG-A exhibited the strongest activity with a proliferation rate of 32.7% at the concentration of 100 μg/mL in 72h, while SCG-N activity was lower at 11.66%. The molecular weight of SCG-A was 4.30×10⁵Da with an α-1,4-D-glucan as its main chain consisting primarily of glucose and galactose with some 1-6-branches.

  Conclusion  The water-soluble polysaccharides and its fractions obtained from the lyophilized S. latifolia powder showed varying in vitro immune activities of promoting the proliferation of rat spleen lymphocytes. The acidic SCG-A had a main chain structure of α-1,4-glucan with 1-6-branches and showed the greatest immunological activity among the 3 polysaccharide materials.