Abstract:

The crude polysaccharide was obtained from Rosa davurica root via hot water extraction method and ethanol precipitation,followed by deproteinization using the Sevage and TCA methods,respectively.After deproteinization,the crude polysaccharide was purified by graded ethanol precipitation method.Herein,the 60% ethanol precipitate was labeled RDRP,and its structure and activity of were further studied.The total sugar content of polysaccharides RDRP was 94.1%,and mainly contained a polysaccharide with an average molecular weight of 13.1 kDa with narrow polydispersity at 1.2,as well as comprised of five monosaccharides including glucose,arabinose,galactose,mannose,and xylose. IR spectrum indicate that it was a neutral glucopyranoside in the α-configuration.In cyclophosphamide-induced immunosuppressive mice test,the spleen and thymus index of mice in each dose group of RDRP were significantly increased(P<0.05，P<0.01),respectively,compared to model group;the white blood cells,red blood cells and platelets in each dose group of RDRP were significantly increased(P<0.05)compared to model group;the immunoglobulin IgG,IgM,IgA and IFN-γ,TNF-α,IL-6 and IL-2 in each dose group of RDRP were significantly increased(P<0.01)compared to model group;the TLR4 and TRAF-6 proteins in each dose group of RDRP were increased significantly(P<0.01),and MyD88 was increased significantly in high-dose group(P<0.01)and showed the increasing trend in other groups;the NF-κB p65 protein also showed the increasing trend in the RDRP groups.Those results implied that the immunomodulatory mechanism of RDRP may be related to the TLR/NF-κB.In this research,the basic structure and immunomodulatory effect and its mechanism of polysaccharide from R. davurica roots were clarified and those data will provide a valuable experimental basis for its development and application.

Key words: Rosa davurica roots, polysaccharide, structure characterization, immunomodulation, TLR/NF-κB