Structural Characterization Of Mesona Chinensis Benth Polysaccharide And Its Protective Effect Against Deoxynivalenol-Induced Intestinal Barrier Damage

Background and purposeThe intestine is an important digestive organ of the human body,responsible for the absorption of food and water and the secretion of intestinal fluid.While playing an important immune role,the intestine can effectively prevent toxic and harmful substances that enter the intestinal cavity with food from entering the blood and other tissues and organs,acting as a barrier.The intestinal barrier consists of four components,namely,biological barrier,chemical barrier,physical(mechanical)barrier,and immune barrier,and each barrier component complements the other and is essential for the intestine to perform its functional activity.However,the presence of many toxic and harmful substances in the diet can damage the intestinal barrier and induce diseases,for example,deoxynivalenol,a fungal toxin,can induce oxidative stress in intestinal cells,disrupt the expression of tight junctions between intestinal cells,and induce a series of diseases such as intestinal inflammation.Deoxynivalenol(DON),also known as vomitoxin,is a highly toxic fungal toxin produced by Fusarium spp.in the class B moniliform mycotoxin family,which is distributed worldwide and has a variety of toxicities,and is classified by WHO as one of the most dangerous naturally occurring food contaminants.Intake of food containing DON can lead to intestinal damage and induce disease,but there is no specific treatment for intestinal damage,mostly symptomatic support treatment,so it is necessary to find new prevention and treatment methods.A large number of studies have shown that polysaccharides,as phytochemically active substances,have a wide variety of biofunctional activities and low toxic side effects on the organism,showing attractive prospects in antioxidant and anti-inflammatory aspects.M.Blume polysaccharides(MBP)or Mesona chinensis Benth gum(MBG)are active substances extracted from the whole grass of M.Chinensis with various biological activities,such as antioxidant,immunomodulatory and hypoglycemic effects,while the protective effect on the intestinal barrier has not been reported.Therefore,the study of the protective effect of M.Blume polysaccharide on DON-induced intestinal barrier damage and the study of its mechanism is of valuable scientific significance to explore the rich resources of Mesona chinensis Benth in China and provide new ideas for the prevention and control of DON-induced intestinal damage.Objective1.The M.blume polysaccharide was extracted and purified,and its physicochemical properties and antioxidant activities in vitro were analyzed,providing a scientific basis for making full use of the M.blume resources.2.Study the protective effect of MBP on DON-induced Caco-2 monolayer intestinal barrier damage model and the regulation of intestinal flora in Simulator of Human Intestinal Microbial Ecosystem(SHIME),to provide new ideas for the prevention and control of the intestinal damage caused by DON.Methods1.The extraction effect was evaluated by extraction rate,the crude polysaccharide was purified using a cellulose anion exchange column DEAE-52 chromatography.The physicochemical properties were characterized by efficient liquid chromatography,gel osmosis chromatography,GC-MS,scanning electron microscopy,and infrared spectroscopy.To then initially evaluate the free radical scavenging ability and total reduction ability of MBP in vitro2.Treat the Caco-2 monolayer cell model and SHIME with DON to study the damaging effect of DON on the intestinal barrier.Meanwhile,MBP intervention was used to study whether MBP protects and improves the intestinal barrier damage induced by DON.Results1.MBP can be obtained by alkali lifting,and initial purification by cellulose DEAE-52 can obtain MBP-C,MBP-1,MBP-2,and MBP-3.MBP-C is a neutral sugar containing type β pyranose,and MBP-3 is an acidic sugar containing both α-and βpyranose.The average molecular masses of MBP,MBP-C,and MBP-3 were 8074.825,7375.595,and 9665.562 Da,respectively.2.MBP has a certain scavenging capacity of hydroxyl radical,superoxide anion radical,ABTS radical,DPPH radical,PTIO radical,and nitroso ions,and has strong total reduction capacity,indicating that MBP has good antioxidant capacity(P<0.05).3.DON can inhibit the proliferation of Caco-2 cells,while MBP has no proliferation toxicity to Caco-2 cells,and improve the growth inhibition caused by DON;DON has oxidative damage and inflammatory effect on Caco-2 cells(P<0.05),while MBP can improve the antioxidant enzyme activity of Caco-2 cells,inhibit the production of reactive oxygen species and inflammatory factors and lipid peroxidation,and has good antioxidant and anti-inflammatory effects(P<0.05).4.DON can inhibit AKP activity and inhibit the expression of tight junction proteins ZO-1,and Occludin,(P<0.05),while MBP can have a protective effect on DON-induced intestinal damage by improving AKP activity,increasing cell tight junction protein expression in Caco-2 monolayers,promoting cell differentiation,and maintaining intestinal barrier integrity(P<0.05).5.MBP can improve the microbial barrier of the gut by regulating the intestinal composition of the SHIME system,improving the abundance of Firmicutes and proteobacteria to improve the imbalance of the SHIME system caused by DON(P<0.05).ConclusionComprehensive physicochemical characterization,in vitro antioxidant,and cell experiments show that MBP has good antioxidant,anti-inflammatory,and intestinal microflora regulation,has a protective effect on DON-induced oxidative stress,inflammation,and intestinal barrier damage,and is a good functional food.