Screening And Functional Evaluation Of Hypoglycemic And Lipid-lowering Lactic Acid Bacteria

Diabetes and obesity are two of the major health problems facing the world today.More than 500 million people worldwide have diabetes,more than 90%of whom are type 2 diabetes(T2DM).The prevalence of obesity is also increasing year by year.Both of these two chronic metabolic diseases can be relieved by long-term medication,but therapeutic drugs are often accompanied by side effects such as gastrointestinal diseases.As a natural,safe and beneficial microorganism without side effects,lactic acid bacteria have been widely used in the prevention and treatment of many diseases.However,most of the functional lactic acid bacteria reported are patented strains of foreign enterprises at present.Only by developing functional lactic acid bacteria with independent intellectual property rights can make the products competitive in the market.Therefore,this paper aims to develop independent intellectual property rights of lactic acid bacteria with the effect of hypoglycemic and preventing obesity,and study its influence on intestinal flora.Firstly,Lactobacillus rhamnosus GG was used as a positive control,and antioxidant capacity,α-glucosidase activity inhibition ability,pancreatic lipase activity inhibition ability,cholate degradation ability and cholesterol clearance ability were used as screening indexes.After,one lactobacillus with good potential hypoglycemic effect(L.fermentum LF3.2)and one lactobacillus with good potential obesity-prevention effect(L.plantarum G1.3)were selected from the 7 strains with independent intellectual property rights.A type II diabetic mouse model was established to study the effects of L.fermentum LF3.2on diabetic symptoms and intestinal flora in T2DM mice.The results showed that both high(10~9 CFU/mouse/day)and low(10~8 CFU/mouse/day)doses of L.fermentum LF3.2significantly improved the symptoms of hyperglycemia,body weight loss,hepatorenal enlargement,reduced total cholesterol,IL-6 and TNF-αlevels,increased HDL cholesterol levels in T2DM mice,and low doses of L.fermentum LF3.2 also significantly reduced serum triglyceride levels.In addition,low doses of L.fermentum LF3.2 increased the species richness and the Bacteroidota/Firmicutes ratio of the intestinal flora of T2DM mice,increased the abundance of beneficial flora such as Clostridia,Verrucomicrobiae,Dubosiella and Akkermansia,and decreased the abundance of pathogenic flora such as Proteobacteria.The low dose of L.fermentum LF3.2 was more effective in improving the symptoms of T2DM and regulating intestinal flora.L.plantarum G1.3 was selected to intervene in mice on high-fat diet to study the preventive effect of L.plantarum G1.3 on high-fat diet-induced obesity and its effect on the intestinal flora.The results showed that both high(10~9 CFU/mouse/day)and low(10~8CFU/mouse/day)doses of L.plantarum G1.3 slowed excessive body weight gain caused by high-fat diets,improved symptoms of hepatorenal enlargement and hepatic steatosis status.High doses of L.plantarum G1.3 significantly reduced total serum cholesterol and LDL cholesterol levels in mice.In addition,high doses of L.plantarum G1.3 increased the species richness of intestinal flora in mice fed high-fat diets,decreasing the abundance of harmful bacteria such as Staphylococcus and increasing the abundance of beneficial bacteria such as Dubosiella,Akkermansia,Bifidobacterium and Lactobacillus.High doses of L.plantarum G1.3 were more effective in preventing obesity.In conclusion,L.fermentum LF3.2 and L.plantarum G1.3 showed good hypoglycemic activity and anti-obesity effects in mice,respectively,which can provide theoretical basis for the development of hypoglycemic and anti-obesity related functional foods.