Purification,chemical modification and immunostimulating activity of polysaccharides from Tremella aurantialba fruit bodies

Ultrafiltration and a series of chromatographic steps were used to isolate and purify polysaccharides from Tremella aurantialba fruit bodies.Three crude fractions（TAP50w,TAP10-50w,and TAP1-10w）,five semi-purified fractions（TAPA-TAPE）,and one purified fraction（TAPA1） were obtained.A sulfated derivative of TAPA1（TAPA1-s） was prepared by chemical modification.The immunostimulating activity of the polysaccharide fractions in vitro was determined using the mouse spleen lymphocyte proliferation assay.Of the three crude fractions tested,cell prolifera-tion rates were increased most by TAP50w.Furthermore,TAPA1-s was markedly more stimulatory than TAPA1,indicating that sulfonation was an effective way to enhance the immunostimulating activity of polysaccharide.