In Vitro Digestion And Fermentation Of Jujube Polysaccharides Extract And Its Protective Effect On Intestinal Barrier In Mice

Polysaccharides are the main functional nutrients in jujubes,with the characteristics of wide source and easy extraction.Studies have shown that jujube polysaccharides have the biological activities of laxative,laxative regulation,intestinal flora,immunity enhancement,anti-tumor and other biological activities.In the early stage of this laboratory,related research was conducted on Fuzao jujube produced from Fuping,and it was clear that its polysaccharide mainly consisted of monosaccharides such as galactose,glucose,galacturonic acid,and arabinose,and had a typical absorption peak of carbohydrate;Polysaccharides have the function of improving the mucosal immune disorders and intestinal flora disorders in mice,and maintaining the relative stability of the body’s immune system.On this basis,this experiment mainly studies the in vitro digestion and digestion characteristics of jujube polysaccharides and the protective effect on the intestinal barrier,providing a theoretical basis for its development and utilization.The main research contents and results are as follows:1.By establishing an in vitro digestion model that simulates a three-step continuous digestion of saliva-gastric fluid-intestinal fluid,the digestion of jujube polysaccharide extract in simulated artificial saliva,gastric juice,and intestinal fluid was studied.The results showed that the jujube polysaccharide extract was not digested in saliva.During the simulation of saliva-gastric juice digestion,the average relative molecular weight of jujube polysaccharide extract decreased significantly,while the reducing end increased significantly,indicating that the glycosidic bond of the polysaccharide part was broken.During simulated saliva-gastric fluid-intestinal juice digestion,the reducing sugar content and average relative molecular weight of polysaccharides did not change significantly.At the same time,the formation of free monosaccharides was not detected throughout the digestion process.It shows that the polysaccharide does not lead to the formation of free monosaccharides after gastrointestinal digestion,and the molecular structure of the polysaccharide has not been completely changed.2.To study the in vitro fermentation behavior of jujube polysaccharide extracts using healthy human fecal flora as a model of fermentation.The results show that the anaerobic cultivation of the jujube polysaccharide extract can make the fermentation environment change from alkaline to acidic;the reducing sugar content shows a trend of increasing first and then decreasing,while the total carbohydrate residue shows a downward trend;The composition of jujube polysaccharides has changed,the content of four kinds of monosaccharides has decreased,and the two kinds of monosaccharides have increased first and then decreased,indicating that jujube polysaccharides may be decomposed and used by intestinal microorganisms during the process of fermentation;Regulate the changes of intestinal microflora,the abundance of the thick-walled phylum is increased at the phylum classification level,and the abundance of the phylum Bacteroidetes and Proteobacteria is reduced;The abundance of Rongella and Bacteroides significantly reduces the abundance of Serratia and Chorophilus,and has certain probiotic functions.3.Using male ICR mice as experimental animals,cyclophosphamide(CTX)was used to construct an intestinal mucosal injury animal model,and the protective effects of jujube polysaccharide extract on intestinal physical barrier,immune barrier,and chemical barrier in mice with intestinal mucosa injury were studied.Its mechanism.The results show that compared with the model group,the jujube polysaccharide extract can maintain the normal physiological state of intestinal tissue and structure,improve the damaged villi length,increase the villi length/crypt depth(V/C)ratio and muscle layer thickness,and increase The expression of tight junction proteins occludin and Claudin-1 indicates that the jujube polysaccharide extract has a protective effect on the intestinal physical barrier of mice with intestinal mucosal injury.In addition,the jujube polysaccharide extract can increase the number of Peyer’s patches and intestinal immune cells in mice with intestinal mucosal injury,and enhance the activity of lysozyme and acid phosphatase secreted by the intestine,indicating that it has an enhanced intestinal immune barrier And chemical barrier functions;mechanism studies have shown that jujube polysaccharide extracts may reduce the expression of MyD88/NF-κB pathway inflammatory factors by up-regulating the expression of MyD88,NF-κB p65 and IL-1β proteins in the intestinal mucosa injured mice.Secretion,to achieve the purpose of anti-inflammatory and enhance intestinal immune function.Conclusion:The jujube polysaccharide extract is relatively stable during in vitro digestion.Although it has been degraded during the simulated saliva-gastric juice digestion process,the molecular structure has not been completely changed;in vitro fermentation studies have shown that it has good probiotic function;jujube polysaccharide The extract can protect the intestinal immune barrier by protecting the intestinal physical barrier,chemical barrier and immune barrier,reducing the damage of cyclophosphamide to the intestinal mucosa,and regulating the expression of cellular inflammatory factors through the MyD 8 8/NF-κB signaling pathway.