In vitro probiotic characterization of Lactobacillus strains from fermented tangerine vinegar and their cholesterol degradation activity

The cholesterol-lowering properties of lactic acid bacteria (LAB) isolated from naturally fermented tangerine vinegar were evaluated. A total of 5 Lactobacillus plantarum strains were evaluated in terms of their in vitro cholesterol-lowering and probiotic profiles. Cholesterol removing, bile salt hydrolysis, antioxidant capacity, antimicrobial activity, cell surface properties (autoaggregation, co-aggregation, adhesion to human Caco-2 cells), acid and simulated gastrointestinal fluids tolerance, hemolytic and resistance to 10 antibiotics were examined. The results indicated that all strains have cholesterol removal and antioxidant properties, antimicrobial and bile salt hydrolase activities, co-aggregation and autoaggregation abilities, as well as the ability to adhere to human Caco-2 cells. None of these strains showed either undesirable hemolytic activity or resistance to some clinically significant antibiotics. Among the isolates, strains NF4 and NF2 showed a >50% rate of cholesterol removal. Significant changes in the adhesion of living and dead cells to cholesterol were observed using scanning electron microscopy. Strains NF3 and NF2 showed better antioxidant activity. Strain NF2 showed the best adherence ability to human Caco-2 cells. Likewise, strain NF4 showed optimal autoaggregation and co-aggregation, notable rates of survival in fluids of the simulated gastrointestinal tract, and the best survival rate and the highest cholesterol-reducing rate (55.8%). These results suggested that L. plantarum NF4 could be used as a potential hypolipidemic probiotic.