| Arctium lappa L.is rich in polysaccharides,which have various physiological effects such as antioxidant,anti-tumor,anti-inflammatory,hypoglycemic,and intestinal probiotic.Zinc is an essential trace element for the human body and plays an important role in regulating body functions.The preparation of polysaccharide zinc by chelating polysaccharides with zinc ion can solve the disadvantages of common zinc supplements,such as high irritation to the gastrointestinal tract and low bioavailability.In this study,Arctium lappa L.polysaccharide zinc was prepared,its structural characterization,stability,bioavailability and immune activity were investigated.The main research contents and results are as follows:（1）Preparation of ALP-ZnOptimization of ALP-Zn by zinc sulfate method through single-factor and response surface tests:the weight ratio of ALP to zinc sulfate was 37:1,the reaction temperature was50℃,the reaction time was 121 min,the reaction p H was 8.6,and the highest chelation rate was 93.21%±0.58%.（2）Structural characterization of ALP-ZnThe heavy-average molecular weight of ALP-Zn was 60,268 Da and the number-average molecular weight was 8646 Da.Fourier infrared spectroscopy showed that a peak caused by Zn-O stretching vibration appeared at 433 cm-1.Thermogravimetric analysis showed that ALP-Zn has good thermal stability.X-ray diffraction analysis showed that ALP-Zn had a non-crystalline structure and the crystallinity decreased after chelation.（3）Evaluation of stability and bioavailability of ALP-ZnThe stability of ALP-Zn was studied under different storage time,storage temperature and p H conditions.The results showed that the temporal and temperature stability of ALP-Zn was reduced,and the storage effect was better in alkaline condition than in acidic condition.In vitro simulated gastrointestinal digestion tests showed that ALP-Zn had higher bioavailability,with dissolution rates of 39.1%and 2.63%in artificial gastric and intestinal fluids,respectively,and the dissolution rates of zinc sulfate was 3.29%and 0.15%.The dialysis rate of ALP-Zn in intestinal fluids was 20.86%,which was 19.83%higher than that of zinc sulfate.（4）Evaluation of immune activity of ALP-ZnThe immune activity of ALP-Zn was investigated by studying the expression of co-stimulatory molecules,cytokine secretion and endocytosis in mouse bone marrow dendritic cells.The results showed that ALP-Zn demonstrated excellent immunological effects on dendritic cells（DCs）.The DCs maturation was induced and the surface expression of CD80and CD86 in DCs were increased after ALP-Zn treatment.ALP-Zn also significantly reduced DC endocytosis and increased cytokine（IFN-γ,TNF-α,IL-1βand IL-6）production. |
PDF Full Text Request