Mustard kimchi consumption reduces cholesterol levels in rats. To identify lactic acid bacteria (LAB) in kimchi which exert this effect, 20 LAB isolates were evaluated for cholesterol reduction in an in vitro screen. The FB111 strain showed the highest cholesterol-lowering activity and was identified as Leuconostoc mesenteroides. This strain was characterized as a potential probiotic through sequential analyses for resistance to gastrointestinal digestion and bile salts, and adhesion to Caco-2 cells. The Caco-2 cells treated with L. mesenteroides FB111 (6-8 log CFU/mL) showed toxicological effect. The reduction of cholesterol uptake in these cells was inhibited by 48.6% compared to the control and significantly higher than that of the Lactobacillus rhamnosus GG (LGG) strain-treated group after 2-h incubation. The levels of NPC1L1, ABCG5, ABCG8, SREBP-1, SREBP-2, and PPARα gene expression were determined by reverse transcription-quantitative polymerase chain reaction analysis. The L. mesenteroides FB111 and LGG inhibited the mRNA expression of NPC1L1 (P < 0.05), whereas the expression of PPARα was increased. Moreover, the FB111 strain also inhibited the expression of SREBP-2 mRNA. Overall, we found that L. mesenteroides FB111 has efficient cholesterol-lowering effects and might be useful as a probiotic in the food industry.
Keywords: Caco-2 cells; Cholesterol absorption; Mustard kimchi; Probiotic.