| Background and objectives:Ulcerative colitis(UC)is a common non-specific intestinal disease,the cause of UC is currently unknown,and the clinical manifestations are diffuse spread of inflammation.In recent years,the global incidence of UC has continued to rise.Although the mortality rate is not high,the long-term symptoms of abdominal pain and blood in the stool put a heavy burden on the physical and mental health of patients.Euphorbia humifusa belongs to the liver and intestine meridian.In clinic,it is mostly used to treat dysentery,enteritis,blood in the stool and other diseases.Although Euphorbia humifusa has been used in the treatment of intestinal diseases,the effect on ulcerative colitis has not been reported,and its mechanism of action needs to be further elucidated.Studies have found that restoring the shape of the intestinal mucosa and improving the imbalance of intestinal flora are important entry points for the treatment of colitis.Therefore,in this research,the effect of Euphorbia humifusa polysaccharide(EHP)on preventing UC and the mechanism were studied by regulating intestinal flora.Methods:1.Extraction of polysaccharides:The polysaccharide is extracted by the traditional water-alcohol precipitation extraction method.After deproteinization,dialysis and vacuum freeze-drying,EHP was obtained.2.Polysaccharide structure identification:the molecular weight,monosaccharide composition,molecular structure and microscopic morphology of EHP were studied by HPSEC-MALLS-RID,HPLC,FT-IR,NMR,SEM and other instrumental analysis methods.3.Polysaccharide absorption characteristics:EHP was labeled with FITC,and a Caco-2 small intestinal absorption model was established to evaluate EHP absorption characteristics.4.Characteristics of in vitro fermentation of polysaccharides:Taking sterile water as a control,in vitro fermentation experiments were carried out in the digestive system by inoculating healthy human volunteers with fecal flora.16s rRNA highthroughput screening was used to sequence the colony composition of fermented samples at different times.5.Effect evaluation and mechanism study:Acute ulcerative colitis model was constructed with dextran sodium sulfate(DSS),and mice were divided into blank group,model group,low,medium and high doses(100mg/kg,200 mg/kg,300 mg/kg)administration group,continuous intragastric administration for 10 days.Results:1.The molecular weight of EHP is mainly composed of two components,7.770 × 106(± 1.699%)Da and 1.757 × 105(±4.213%)Da,and the surface is rough and grainy.It is mainly composed of galactose(55.33%),glucose(2.70%)and galacturonic acid(8.30%).It is mainly an acidic polysaccharide with β-type glycosidic bonds and a small amount of α-glycosidic bonds.2.It was found that the apparent permeability coefficient at 6 h was 1.891±0.10×106 cm·s-1,indicating poor absorption.3.Compared with the control group,the carbohydrate utilization rate of the polysaccharide group was higher than that of the blank group,and the content of total short-chain fatty acids,acetic acid,propionic acid and valeric acid increased significantly(P<0.05).At the same time,EHP can increase the relative abundance of beneficial bacteria(Bifidobacterium,etc.)and reduce the relative abundance of harmful bacteria(E.coli Shigella,etc.).4.Pathological sections found that EHP can improve the pathological state of the colon.Compared with the model group,the administration group increased and decreased the level of IL-6 in the colon and increased the level of IL-10(P<0.05).Conclusions:1.EHP is a kind of natural macromolecular polysaccharide with probiotic activity,which can increase the production of short chain fatty acids(SCFAs)and increase the relative abundance of beneficial bacteria.2.In vivo experiments showed that EHP had protective effect on mice with acute ulcerative colitis,inhibited the signal transduction of pro-inflammatory factors and increased the expression of anti-inflammatory factors. |
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