Bioactivity-guided investigation for isolation and immunoregulatory potential of polysaccharides from Dendrobium chrysotoxum stems

Abstract

A new immunoregulatory polysaccharide (DCP-W4) with a relative molecular mass of 1.37 × 104 Da was separated and purified from the stems of Dendrobium chrysotoxum under the guidance of immunoregulatory activity assay based on the small intestinal Peyer’s patch-mediated proliferation of bone marrow cells. Analysis of physicochemical features showed that DCP-W4 was a glucomannan consisting of glucose and mannose in a molar ratio of 3.0 : 1.0. Oral administration of mice suggested that DCP-W4 could significantly influence the body’s immune activity, which was evidenced by its ability to change the indexes of immune organs including spleen and thymus, the proliferation of bone marrow cells mediated by the supernatant of Peyer’s patch cells, the balance of Th1/Th2 through effectively regulating the secretion and ratio of IFN-γ and IL-4, the proportion and differentiation status of different immune cells including T-cells, dendritic cells and macrophages, and the production of sIgA as well as β-defensins and mucin-2 in the small intestine or in the spleen of mice. These results indicated that DCP-W4 was a polysaccharide with a hopeful potential for the modulation of intestine immune system and systemic immune system.