Studies on Isolation and Screening of Lactic Acid Bacteria from Pickle and Its Improvement Effect on Oxidative Stress Level in Mice

Abstract

Twelve strains of lactic acid bacteria were isolated from naturally fermented pickles at a Chongqing farmhouse in order to screen for in vitro resistance and antioxidative impact in vivo. 4 strains are Lactobacillus plantarum, 7 strains are Lactobacillus fermentum, and 1 strain is Lactobacillus brevis, according to 16S rDNA species analysis. Using artificial gastric juice (pH 3.0) and 0.3 percent bile salt, the in vitro resistance of lactic acid bacteria was examined, and it was discovered that all 12 Lactobacillus strains exhibited good resistance in vitro. The survival rate of 10 Lactobacillus strains in artificial gastric juice at pH 3.0 for 3 hours was greater than 80%, and the survival rate of 2 Lactobacillus strains in 0.3 percent bile salt was greater than 60%. The experimental strain was L. fermentum CQPC-11, which has good resistance in vitro and is a food strain, and its improvement effect on activated carbon ice water-induced oxidative damage in mice was evaluated. The findings revealed that the enzyme activities of T-SOD, GSH-Px and CAT in the serum of mice in the H-LF CQPC11 group were 67.73±5.42 U/mL, 2742.35±107.35 enzyme activity units, and 136.59±18.72 U/mL, respectively, which were significantly higher than the model group (p<0.05), and the content of MDA was 1.99±0.14 nmol/L, which was significantly lower than the model group (p<0.05). In summary, L. fermentum CQPC-11 not only has good resistance to gastric acid and bile salts, but also reduces oxidative stress response in oxidative stress model mice. Subsequent experiments will be used to investigate the unique mechanism of this strain's anti-oxidant action, providing a basis and strains for the development of new micro-ecological preparations and functional lactic acid bacteria food.