Analysis On The Mechanism And Specificity Of Undaria Pinnatifida Polysaccharides Regulating Gut Bacteria

Undaria pinnatifida is a kind of temperate brown seaweed,which is rich in carbohydrates,protein,unsaturated fatty acids,carotenoids and other nutrients,and plays an important role in human healthy diet.U.pinnatifida polysaccharide is the representative active ingredient of U.pinnatifida,mainly including sulfated polysaccharide(UPSP)and sodium alginate(UPA).Studies have shown that U.pinnatifida polysaccharides have antitumor,antiviral,antioxidant and anticoagulant activities,which are closely related to the interaction between polysaccharides and gut bacteria.However,the regulatory effect and mechanism of U.pinnatifida polysaccharides on gut bacteria are still unclear.The study showed that the U.pinnatifida polysaccharide: UPSP,UPA and mixed polysaccharide(UPP)were improved the weight gain of high-fat mice induced by high fat diet,increased liver and cecum weight,and the accumulation of epididyma,improved the levels of ABCG8、PGC-1α and PPAR-γ in the liver of high fat mice,reduced the levels of TC、TG、LDL-c and MDA in the serum and liver,increased the level of HDL-c and CAT,improved fat accumulation and lipid metabolism abnormalities,reduced the level of lipid polysaccharide in the body tissue,regulated the level of inflammatory factors and the content of short chain fatty acids,improed the disease of colitis that is caused by high-fat diets,reduced the permeability of the intestine to maintain the integrity of the intestinal barrier.However,compared with the UPSP and UPA groups,the epididymal fat and liver weight of the mice supplemented with mixed polysaccharide(UPP)decreased,the adipocytes were reduced,the serum LDL-C,TG and LPS content decreased,the liver IL-10 level increased,and the IL-6 and LPS levels decreased.These results suggest that the diversity of polysaccharides can improve the physiological changes such as fat accumulation,abnormal lipid metabolism and inflammation caused by high fat diet.Supplement of U.pinnatifida polysaccharide could adjust dysregulation of gut bacteria in high-fat mice,and reduce the level of the Firmicutes,increased the level of the bacteroidetes.In vitro,the experimental results show that the diversity of polysaccharide can improve the richness of the Bacteroides,and further illustrate the effect of polysaccharide diversity on the stability of gut bacteria.U.pinnatifida polysaccharides can improve the related diseases induced by high fat diet by regulating intestinal flora.The diversity of polysaccharides is helpful to regulate gut bacteria and increase the abundance of Bacteroides.In order to further study the regulation mechanism of the polysaccharide on the gut bacteria,the animal model of the dietary fiber deficiency confirmed that the variety of the U.pinnatifida polysaccharide can increased the thickness of the colon,increased the level of ZO-1 and Occludin to maintaining close connections between cells,Reduced the permeability of the intestine to maintaining the steady balance of the intestine;increased the level of the IL-10 in mice,reduced the level of the IL-1、IL-6 and the TNF-α levels,improved the disease of colitis caused by low dietary fiber eating.The change of the SCFA and serum metabolites of mice in mice were adjusted.The gut bacteria of the mice were adjusted,and reduced the degradation of gut bacteria on the intestinal mucous layer.U.pinnatifida polysaccharides can improve the intestinal microecological environment by regulating the structure of gut bacteria,and the diversity of polysaccharides is helpful to maintain the intestinal homeostasis structure.The results showed that the polysaccharide was adjusted to protect the microecological balance of the gut and maintain the health of the body.Increasing the diversity of polysaccharides helps to improve the richness and diversity of the gut bacteria,and can change the use strategy of the bacillus and protect the microecological environment of the gut.This provides a new idea for the extraction and separation of polysaccharides,which provides the basis for the development of composite polysaccharide products.