The Screening And Functional Evaluation Of Uric Acid-lowering Lactic Acid Bacteria

In this paper,30 tested strains were used as the research object,and HPLC was used to screen for strain with higher decomposition nucleoside rate.To evaluate its prebiotic potential,acid resistance,bile salt resistance,gastrointestinal transport,adhesion,bacteriostatic ability and antibiotic sensitivity were tested.Its functions were evaluated for experiments such as XOD-xanthine reaction system and LPS-THP-1 inflammation model,etc.The results of the study are as follows:(1)Four lactic acid bacteria with higher nucleoside(guanosine,inosine)degradation rate were selected from 30 candidate strains with the method of HPLC,i.e,strains WX-94,AM60-10PH4,SS-9,and SD-H9.The degradation rates of WX-94 and AM60-10PH4 to guanosine and inosine reached 100%,and the degradation rate of SS-9 and SD-H9 to guanosine reached more than 90%,but the degradation rate of inosine was relatively low,68.18%and 49.45%,respectively.(2)The probiotic potential for four lactic acid bacteria was evaluated,and the results showed that the strains WX-94,SS-9,and SD-H9 had a good potential to reduce uric acid.Among them,SS-9 had the highest survival rate after gastrointestinal transit which reached 58.40%.SD-H9 had the strongest adhesion capacity,reaching 9.5±0.8 CFU/cells,and was sensitive to 13 antibiotics.And the above three strains of bacteria of Escherichia coli,Staphylococcus aureus,Pseudomonas aeruginosa and Enterobacter cloacae had different degrees of inhibition,respectively.(3)The inhibitory effects of the above 3 strains on XOD activity were studied,and the results showed that cell-free excretory supernatants(CFS),cell-free extracts(CFE)and skim milk fermentation supernatant of the 3 strains all had different inhibitory effects on XOD.And within a certain range,with the increase in sample,the inhibition rate of XOD also increased gradually.(4)The clinical manifestations of hyperuricemia(gout)were simulated by establishing an inflammatory model of LPS-THP-1.When the test strain was cocultured with LPS-THP-1,it was found that the strains WX-94 and SS-9 reduced the secretion of interleukin IL-6(P<0.05)in inflammatory model cells significantly.SS-9 and SD-H9 reduced the secretion of IL-1?(P<0.05)significantly.All three strains had the potential for improving the inflammatory response.(5)The CFE,CFS and skim milk supernatant of strains WX-94,SS-9,and SD-H9 all had scavenging ability to superoxide anion,DPPH and hydroxyl free radical in varying degrees,but the reductive capacity of each strain was weak.At the same time,the skim milk fermentation supernatants of the above three strains had all inhibited ACE to varying degrees,of which SD-H9 skim milk fermentation supernatant(24h)on the inhibition rate of ACE could be as high as 80.04 ± 3.66%.However,the degradation of cholesterol and the inhibition effect of ?-glucosinase of 3 strains was not obvious.