Characterisation of Lactobacillus fermentum SM-7 isolated from koumiss, a potential probiotic bacterium with cholesterol-lowering effects

BACKGROUND: Lactic acid bacteria (LAB) have been demonstrated to have cholesterol‐reducing effects in many studies. RESULTS: Lactobacillus fermentum SM‐7 screened from ten LAB strains isolated from koumiss, a fermented milk drink, reduced cholesterol by 66.8%. It also showed acid and bile tolerance as well as antimicrobial activity against pathogenic Escherchia coli and Staphylococcus aureus. Lactobacillus fermentum SM‐7 cells assimilated 61.5% and co‐precipitated and absorbed 38.5% of the cholesterol in the media. Co‐precipitation of cholesterol with cholic acid increased rapidly at pH levels below 6. In vivo experiments using L. fermentum SM‐7 on artificially induced hyperlipidaemial ICR mice significantly decreased serum total cholesterol and total triglyceride levels, low‐density lipoprotein cholesterol concentrations and atherogenic index (P < 0.01), while serum high‐density lipoprotein cholesterol concentrations did not increase significantly (P > 0.05). The body weight and liver weight/body weight ratio of SM‐7 groups were lower than those of mice on a high‐cholesterol diet that were not given lactobacilli. There was no bacterial translocation in the liver, spleen or kidney of experimental mice. CONCLUSION: The results suggested that L. fermentum SM‐7 is a potential probiotic bacterium with cholesterol‐lowering effects. Copyright © 2010 Society of Chemical Industry