Purification,Structural Characterization Of Polysaccharide From Suaeda Salsa And Its Induction Of Apoptosis In MCF-7 Cells

ObjectiveSuaeda salsa(Bunge),is an annual herbaceous plant that contains various bio-functional macromolecules.The aim of this experiment was to establish a method for the isolation and purification of Suaeda salsa polysaccharide,and to study its structural characteristics and antitumor activity.MethodsThe crude polysaccharides were extracted from Suaeda salsa by water-soluble extraction,and the yield was 4.2%after freeze-drying.The protein was removed by Sevag reagent and decolorized by activated carbon adsorption,the crude polysaccharide of S.salsa was further separated and purified by DEAE-52 cellulose column and Sephadex G-75 gel column to obtain uniform polysaccharide component SSP2-2.The HPGPC,PMP-HPLC,IR and NMR was used to identify the purity and structure of homogenous polysaccharides.The antitumor activities of homogenous polysaccharides were evaluated by MTT assay,Hoechst 33342staining,MMP assay,flow cytometry analysis and western blot analysis.ResultsThe M_w of SSP2-2 was about 53.8 kDa.The SSP2-2 comprised of mannose,rhamnose,glucuronic acid,galacturonic acid,galactose,xylose with a molar ratio of0.6:8.0:1.0:83.6:5.0:7.2.The FT-IR spectrum of SSP2-2 indicates that SSP2-2contains characteristic absorption of uronic acid and?-glycosidic bond.The NMR indicated that SSP2-2 was a pyranose and a C-1 linkage was present.The MTT assay showed that SSP2-2 inhibited MCF-7 cells proliferation significantly.The Hoechst 33342 staining experiment suggested that SSP2-2 caused the characteristic of nuclear shrinkage and nuclear fragmentation.The Flow cytometry analysis showed that SSP2-2 can induce MCF-7 cells apoptosis.Further studies revealed that SSP2-2 induced the reduction of mitochondrial membrane potential in MCF-7 cells.The Western blot analysis showed that the expression of Bcl-2 was decreased,and the expression of Bax,cytochrome C,Caspase-3 and Caspase-9was increased,indicating that SSP2-2 induces apoptosis through mitochondrial pathway.ConclusionsIn this study,a uniform polysaccharide component,SSP2-2,was isolated and purified from Suaeda salsa.SSP2-2 has a molecular weight of about 53.8 kDa,and it is mainly composed of galacturonic acid.The SSP2-2 could induce the apoptosis of MCF-7 cells via the mitochondrial pathway.