Study On The Preparation,Characterization And Bioactivity Of Astragalus Polysaccharide Complex

APS is one of the main active ingredients of Astragalus.It has the functions of anti-oxidation,boost immunity,anti-tumor and antibacterial.The molecular modification of APS can greatly improve the bioactivity of the polysaccharide or generate new biological activity,and also provides a theoretical basis for further exploring the structure-activity relationship of APS.The purpose of this thesis is to study the optimization of preparation technology,structure characterization and biological activity screening of APS-Fe and APS-Cu.The specific research contents and results are as follows:?1?APS-Fe was synthesized from APS and Ferric trichloride under alkaline conditions,yield was 28.44±0.05%.APS-Fe was characterized by FTIR,UV-vis,TG-DSC,X-ray and SEM.The results showed that Ferric ion was successfully combined with APS.The iron content in APS-Fe was determined by UV-vis and ICP-OES,respectively 57.36±0.22 mg/g and 53.95±0.17 mg/g.Rutin was used as a positive control,Antioxidant tests were performed using DPPH,ABTS,OH and total reducing power.The antioxidant ability of APS and APS-Fe was evaluated.The results showed that APS and APS-Fe had certain resistance Oxidation ability,it's antioxidant ability showed a dose-dependent relationship under tested condition,and the antioxidant ability of APS-Fe was slightly lower than APS.In addition,the results of NO assay showed that APS,APS-Fe and ferric trichloride could stimulate RAW264.7 cells to release NO in a dose-dependent manner.APS-Fe has a very significant promoting effect at low concentration?P<0.01?,indicated that APS-Fe can effectively activate macrophage RAW264.7,thus playing an immunoregulatory role.At the same concentration,the order of immunoregulatory activity was as follows:APS-Fe>ferric trichloride>APS.?2?APS-Cu was successfully synthesized by chemical method.The effects of APS:CuSO₄,reaction time,pH value,and reaction temperature on the preparation of APS-Cu were investigated through a single factor experiment.The appropriate preparation conditions were obtained by response surface method:copper sulfate ratio was 1:2.12,reaction time was 3.09 h,pH value was 7.54 and reaction temperature was 80?.Under these conditions,the theoretical yield of the composite was 153.46%,and the actual yield of the complex was 152.96±0.46%.The antibacterial activity screening results showed that the antibacterial effect of APS-Cu was better than APS,and the inhibitory effect of APS-Cu on Staphylococcus aureus was better than other strains.In this experiment,OD₅₉₀90 was used as an indicator.MIC value of APS-Cu on Staphylococcus aureus was 0.625 mg/mL,the MIC value concentration on E.coli was 1.25 mg/mL,and the MIC value concentration on Salmonella was 1.25 mg/mL,the MIC value concentration on Candida albicans was 1.25 mg/mL.