Evaluation of lactic acid bacteria isolated from fermented mustards in lowering hypercholesterol by using bile salt hydrolase (BSH) activity and bile salt de-conjugation

Abstract

This work evaluates lactic acid bacteria (LAB) obtained from fermented mustards for lowering cholesterol. The LAB strains’ ability to reduce cholesterol in vitro was determined using activity of bile salt hydrolase (BSH) and deconjugation of bile salt in vitro. The LAB strains were examined for their ability to resist acid and bile salt. Strains that can reduce cholesterol adhere to Caco-2 cells and they were identified. 9 LAB isolates had higher total BSH activity (1.07 to 1.92 U/mL) than the reference strains. BSH specific activity range from 1.33 to 3.13 U/mg. Due to different protein contents in the cell extracts, there was no good correlation between the exact BSH activity and total BSH activity by most of the isolates. All of the isolates deconjugated sodium glycocholate, freeing cholic acid, from 1.02 to 2.64 mM. The tested isolates deconjugated sodium glycocholate at different levels. All tested strains exhibited acid tolerance and bile tolerance; they can survive well at pH 3.0 for 3 h and bile tolerance for 24 h. Adhesion of the tested strains to the Caco-2 cell lines, strain B0007 and B0008 strongly adhere in comparison to the control strains and other isolated strains. These results demonstrated positive effect of isolates on BSH activity, deconjugation and thereby leading to the probiotic potential of lowering cholesterol. Key words: Lactic acid bacteria, acid- and bile-tolerant, bile salt hydrolase activity, deconjugation, adhesion activity.