Polysacchardies In Large Yellow Tea Modulate Gut Microbiome In HFD Fed Mice

The changes in intestinal microflora structure are closely related to obesity and the metabolic syndrome induced by it.Long-term high-fat diets lead to intestinal flora disturbance are one of the major causes of obesity.Our previous research found that Larger Yellow Tea has the functions of regulating blood sugar,reducing fat and lipids,while polysaccharides are the main component of Larger Yellow Tea.Whether or not,the polysaccharides in Larger Yellow Tea have affected the weight-loss and lipid-lowering effects by regulating intestinal flora,which has not been reported yet.The purpose of this study was to study the modulation of tea polysaccharides in Larger Yellow Tea on intestinal microflora and human intestinal flora in high-fat diets.Firstly,the tea polysaccharides in Larger Yellow Tea were prepared by water extraction and alcohol precipitation method,and then their antioxidative activities were studied in vitro.The effects of tea polysaccharides on intestinal flora and intestinal barrier functions were studied by high fat diet-induced obesity mice model.We further studied the regulation of tea polysaccharides on human intestinal microflora and the changes of short chain fatty acids of polysaccharides metabolites by simulating the gastrointestinal bionic system in vitro.In vitro antioxidant studies showed that Larger Yellow Tea polysaccharide has the ability to scavenge DPPH free radicals and hydroxyl radicals with IC50 of 63 g/mL and 757 g/mL,respectively.In high-fat-induced obese mice models,tea polysaccharides were found to effect on body weight,and intestinal redox status analysis showed that tea polysaccharides significantly(p<0.05)increased total anti-colonal resistance in high-fat diet fed mice.Oxidative capacity(T-AOC)increased glutathione peroxidase(GSH-Px)levels;significant(p<0.05)decreased malondialdehyde(MDA)content in high-fat diet fed mice.The analysis of blood inflammatory cytokines showed that tea polysaccharides reduced the levels of plasma tumor necrosis factor(TNF-?)and interleukin-1? in high-fat diet fed mice;tea polysaccharides significantly(p<0.05)up-regulated high-fat diets feeding mice intestinal tight junction protein claudin-1 expression.16 SrDNA sequencing analysis of changes in intestinal flora after intervention with tea polysaccharides found that tea polysaccharides reduced the proportion of Firmicutes/Bacteroides.It also reduced the relative abundance of Lachnospiraceae,Clostridium-ramsum,Erysipelotrichaceae,and Desulfovibrionaceae associated with obesity and dysbacteriosis of the intestinal flora.In addition,tea polysaccharides also increased the ratio of Butyricimonas,Prevotella,and Bifidobacterium to polysaccharide metabolism and potential inhibition of obesity.In vitro simulating the gastrointestinal tract biomimetic system were studied,the modulation of tea polysaccharides on human intestinal flora found that tea polysaccharides increased the biodiversity of human intestinal flora,promoted the proliferation of Prevotella,Butyricimonas,Bifidobacterium,and Faecalibacterium-prausnitzii,and inhibited such as Enterococcaceae,Clostridium-perfringens conditional pathogenic bacteria proliferation,promoted the fermentation process of short-chain fatty acids in the production of propionic acid and lactic acid.Conclusion: Tea polysaccharide has antioxidant activity,which can regulate the disorder of intestinal flora induced by high-fat diet,may inhibit the growth of harmful bacteria associated with obesity,possibly may promote the proliferation of beneficial bacteria Bifidobacterium and also can increase intestinal short-chain fatty acids(SCFA)depending on potential of intestinal barrier function.