Study On The Preparation And Biological Activities Of Selenized Crassostrea Gigas Polysaccharides

Crassostrea gigas is a kind of invertebrate and contains plenty of trace elements and glycogen;in addition,C.gigas can protect liver and lower blood sugar and urine sugar;moreover,it has good nutritional value and medicinal value.In this paper,Selemzed C.gigas polysaccharide(SeCAG)was prepared from C.gigas polysaccharide(CAG)which were produced in laboratory,and its physicochemical properties and biological activities were studied to provide basic data for the further study of SeCAG.The main results are as follows:1.SeCAG were produced by nitric acid as a catalyst,sodium selenite and polysaccharide as reaction raw materials,and the optimal process conditions of producing SeCAG were optimized:CAG:sodium selenite=1:1.2,the volume fraction of nitric acid is 0.3%,the reaction temperature 1s 70?,and the reaction time is 10 h.The selenium content in SeCAG was calculated by HPLC.Under this condition,the selenium content of SeCAG was 81.95 mg/g,and the yield was 27.4%.2.SeCAG was separated and purified by cellulose DE-52.The characteristic absorption peak of selenite in the vicinity of 762cm-1 was analyzed by Fourier transform infrared spectroscopy(FTIA),which indicated that there was Se=O bond in the CAG after selenization,which means the SeCAG was produced after selenization.Nuclear magnetic resonance 13C-NMR spectra indicated that a substitution reaction occurred at the C-3 or C-2 atomic position in SCGP.3.In vitro antioxidant experiments,SeCAG scavenged free radicals effectively,and have iron reducing power.In vitro anti-tumor experiments,the effects of SeCAG on cell activity,apoptosis and cell cycle of tumor cells in vitro were studied by MTT and flow cytometry.Compared with CAG,SeCAG had inhibitory effect on the activity of two tumor cells(Hela,HepG2),and the effect was most obvious when the concentration was 200 ?g/ml.The results of flow cytometry showed that SeCAG could promote the apoptosis of Hela and HepG2 cells,and the effect on Hela cells was significant.Cell cycle results showed that SeCAG inhibits tumor cell growth by acting on different stages of mitosis in both tumor cells.4.The cck-8 was used to study the cell activity of macrophages.With the increase of SeCAG concentration,the cell activity of macrophages was significantly promoted.When the concentration of SeCAG was 200 ?g/ml,it significantly promoted the ability of macrophages to phagocytose neutral red and release nitric oxide(NO).High concentration of SeCAG stimulated macrophages to secrete IL-6,IL-10 immune factors.