RESUMO
Objective To investigate the physicochemical properties and immunomodulatory activities of crude polysaccharides and their fractions from Sophorae Flavescentis Radix. Methods The crude polysaccharide (SFP-100) was obtained successively by boiling Sophorae Flavescentis Radix in water, ethanol precipitating, dialyzing and freeze drying. SFP-100 was separated withDEAE-cellulose column to obtain three fractions, and these fractions were fruther separated with Sephadex G-100 column to obtain their sub-fractions. The sugar content was determined by phenol-sulfuric acid method, the molecular distribution was determined with gel filtration chromatography, and the monosaccharide composition was analyzed with capillary electrophoresis after PMP derivatization. The immunobiological activities were estimated by measuring the proliferation of mouse spleen lymphocytes as well as the IFN-secretion in mouse splenocytes and the TNF-α secretion in mouse peritoneal macrophages. Results The yield of SFP-100 from Sophorae Flavescentis Radix was 4.83％ and sugar content was 71.62％. SFP-100 was separated into three fractions SFP-100-A, SFP-100-B and SFP-100-C, whose yields were 3.5％, 25.6％ and 16.7％, and the sugar content was 85.99％, 72.09％ and 24.30％, respectively.The monosaccharide composition and their molar ratio for SFP-100-A, SFP-100-B and SFP-100-C were Ara∶Glc∶Gal=7.16∶91.02∶1.82, Xyl∶Ara∶Glc∶Rha∶Gal∶GalA=0.05∶1.00∶0.85∶0.04∶0.35∶0.43, and Xyl∶Ara∶Glc∶Rha∶Gal∶GlcA∶GalA=0.20∶1.00∶0.33∶0.36∶0.45∶0.55∶14.37, respectively. SFP-100-B was further separated into two sub-fractions SFP-100-B-a and SFP-100-B-b with Sephadex G-100, and the other two sub-fractions SFP-100-C-a and SFP-100-C-b were also obtained with the same Sephadex G-100 from SFP-100-C. SFP-100-B-a showed a main wide peak, which had the relative molecular weight 1.02×105 and monosaccharide composition Ara∶Glc∶Rha∶Gal = 1.00∶0.06∶0.02∶0.29. Meanwhile, the relative molecular weight and monosaccharide composition were 5.43×104 and Xyl∶Glc =1.00∶3.81 for the main peak of SFP-100-C-a, and 2.75×104 and Ara∶Glc∶Rha∶Gal∶GlcA∶GalA=1.00∶2.10∶0.57∶0.74∶1.09∶33.75 for the main peak of SFP-100-C-b, respectively. The crude polysaccharides SFP-100 and its fractions, SFP-100-B and SFP-100-C, as well as the sub-fractions, SFP-100-B-a, SFP-100-B-b and SFP-100-C-a, increased the proliferation of spleen cells, all in a dose-dependent manner. Further, SFP-100 could improve the secretion of IFN-γ and TNF-α in spleen cells, while SFP-100-B, SFP-100-C, SFP-100-B-a and SFP-100-B-b could stimulate the secretion of IFN-γ. Conclusion The crude polysaccharides of Sophorae Flavescentis Radix and their fractions showed a good immunomodulatory activity, which may be related to the clinical use of Sophorae Flavescentis Radix for the anti-HBV and anti-inflammatory therapy.