In vitro screening and probiotic evaluation of anti-obesity and antioxidant lactic acid bacteria

In this study, an in vitro screening method for lactic acid bacteria (LAB) with anti-obesity and antioxidant effects was developed. We first screened high cholesterol-lowering LAB from the traditional fermented food water kefir. Among the screened LAB, there were 12 strains with a cholesterol degradation rate over of 60%. The 12 strains were ranked from highest to lowest cholesterol degradation ability, and the top five strains were selected for subsequent tests to determine their ability to lower triglycerides, inhibit α-amylase and α-glucosidase, and LAB with great anti-obesity and antioxidant effects were screened in vitro by determining their ability to inhibit Enterobacter cloacae and their antioxidant activity. A comprehensive evaluation model was then combined with principal component analysis: Y = 0.513Y1+0.229Y2+0.137Y3+0.121Y4. Lactobacillus rhamnosus S51, Lactobacillus plantarum S184, and Lactobacillus fermentum S7 had better anti-obesity and antioxidant potential. The cholesterol-lowering ability of S51 was 69.90%, the triglyceride-lowering ability was 53.72%, α-amylase, and α-glucosidase inhibiting ability was 69.97% and 31.49%, respectively, and Enterobacter cloacae inhibiting ability was 3.43 cm. Its IC scavenging ability of DPPH free radical was 90.47%, which was equivalent to 27.98 μg/mL Trolox standard solution, the CFE scavenging capacity for hydroxyl radicals was 60.99%, and the total reducing power of CFE was equivalent to 513.37 μmol/L l-cysteine hydrochloride. S51, S184, and S7 were eligible for probiotic conditions. The results of the study provide a theoretical basis for the screening of LAB with anti-obesity and antioxidant effects in vitro.