Study On Extraction And Immunomodulatory Mechanism Of A Polysaccharide From Solanum Nigrum Linne

The purpose of this study was to extract an active polysaccharide fraction from Solanum nigrum and explore its immunomodulatory activity and specific mechanism in vivo and in vitro.Crude Solanum nigrum Linne polysaccharide was first extracted from Solanum nigrum by boiling and alcohol precipitation.Then the crude polysaccharide was purified on DEAE fast flow ion-exchange column and Sephacryl TM S-300 HR gel column to obtain a homogeneous polysaccharide fraction named SNLP-1 with immune activity.High performance liquid chromatography(HPLC)suggested the weight-average molecular weight(Mw)of SNLP-1 was 148.6 kDa.Griess and ELISA assays suggested that SNLP-1 activated macrophages and promoted the release of NO and secretion of cytokines(TNF-?and IL-6)in vitro.In lung cancer mice,SNLP-1 not only reduced the tumor weight of lung cancer mice,but also increased the index of thymus and spleen.The results of flow cytometry revealed that the ratio of T lymphocyte subsets CD4~+/CD8~+and the concentration of serum Th1 cytokines(IFN-?,IL-2,TNF)in mice was induced by SNLP-1.QRT-PCR and western blot showed that SNLP-1 upregulated the expression level of TLR4 and its downstream key nodes MyD88?TRAF-6?p-NF-?B and p-c-jun in vivo and in vitro.These results indicated that the homogeneous polysaccharide fraction SNLP-1,extracted and purified from Solanum nigrum had immunomodulatory activity in vivo and in vitro,and TLR4-MyD88 signal pathway was one of the mechanisms of its effect.