Screening of lactic acid bacteria with cholesterol-lowering and triglyceride-lowering activity in vitro and evaluation of probiotic function

To screen the lactic acid bacteria with cholesterol-lowering and triglyceride-lowering activity in vitro and evaluate their probiotic function. By plate separating, cholesterol-lowering and triglyceride-lowering activity in vitro were determined; and by evaluating the probiotic functions, including tolerances to simulated gastric and intestinal juice, the antibacterial spectrum, and the adhesion ability to Caco-2 cells, the probiotic strains with cholesterol-lowering and triglyceride-lowering activity in vitro were screened, and then were identified by phenotypical and physiological tests and 16Sr DNA. Finally, the cholesterol-lowering and triglyceride-lowering activity in vivo of the strains were evaluated using male Sprague-Dawley rats. Two strains L2-16 and L2-73 with stronger cholesterol-lowering and triglyceride-lowering activity in vitro, stronger tolerance to simulated gastric and intestinal juice and adhesion ability to Caco-2 cells, and wider antibacterial spectrum were screened from traditional Chinese fermented cucumber and were identified as Lactobacillus acidophilus and Enterococcus faecalis, respectively. Compared with a hyperlipidemia diet without lactic acid bacteria, the diet supplemented with Lactobacillus acidophilus L2-16 and Enterococcus faecalis L2-73 significantly reduced serum total cholesterol, triglycerides, and low-density lipoprotein cholesterol levels, and liver total cholesterol and triglyceride levels in rats (P < 0.05). Moreover, the diet supplemented with Lactobacillus acidophilus L2-16 and Enterococcus faecalis L2-73 significantly increased the fecal elimination of bile acids (P < 0.05). Lactobacillus acidophilus L2-16 and Enterococcus faecalis L2-73 may have application prospect in the production of some fermented foods such as fermented vegetables, milk, or meat, and probiotic preparations with the function to lower the serum lipid and liver lipid levels.