Screening and characterization of lactic acid bacterial strains that produce fermented milk and reduce cholesterol levels

Abstract

ObjectiveTo screen for and characterize lactic acid bacteria strains with the ability to produce fermented milk and reduce cholesterol levels.MethodsThe strains were isolated from traditional fermented milk in China. In vitro and in vivo evaluation of cholesterol-reduction were used to identify and verify strains of interest. Characteristics were analyzed using spectrophotometry and plate counting assays.ResultsThe isolate HLX37 consistently produced fermented milk with strong cholesterol-reducing properties was identified as Lactobacillus plantarum (accession number: KR105940) and was thus selected for further study. The cholesterol reduction by strain HLX37 was 45.84%. The isolates were acid-tolerant at pH 2.5 and bile-tolerant at 0.5% (w/v) in simulated gastric juice (pH 2.5) for 2 h and in simulated intestinal fluid (pH 8.0) for 3 h. The auto-aggregation rate increased to 87.74% after 24 h, while the co-aggregation with Escherichia coli DH5 was 27.76%. Strain HLX37 was intrinsically resistant to antibiotics such as penicillin, tobramycin, kanamycin, streptomycin, vancomycin and amikacin. Compared with rats in the model hyperlipidemia group, the total cholesterol content in the serum and the liver as well as the atherogenic index of rats in the viable fermented milk group significantly decreased by 23.33%, 32.37% and 40.23%, respectively. Fewer fat vacuoles and other lesions in liver tissue were present in both the inactivated and viable fermented milk groups compared to the model group.ConclusionThese studies indicate that strain HLX37 of L. plantarum demonstrates probiotic potential, potential for use as a candidate for commercial use for promoting health.

Novel probiotic lactic acid bacteria isolated from indigenous fermented foods from West Sumatera, Indonesia

“…Guan et al . [ 29 ] reported that L. plantarum (HLX37) isolated from fermented milk survived well in 0.3% bile salts at a rate of 54.68% and at an incubation period of 4 h.…”

Self-reinoculation with fecal flora changes microbiota density and composition leading to an altered bile-acid profile in the mouse small intestine

“…BSH-active probiotics can be a promising delivery vehicle for promoting increased bile acid deconjugation in the gut. Our study emphasizes the importance of controlling for selfreinoculation when using mice to study the effects of BSH-active microbial strains or probiotics [48,[93][94][95][96][97][98] (especially those with high selectivity for particular bile acid conjugates [47,82,85]) because conventional (coprophagic) mice already have pronounced BSH activity in their small intestines. A non-coprophagic mouse may be a better animal model in such studies.…”

“…Our study suggests that self-reinoculation with live fecal flora in laboratory mice could both interfere with and introduce inconsistencies in live probiotic administration regimens. As has been stated earlier, particular attention should be given to self-reinoculation and its effects on the small intestine bile acid profile in studies aiming to evaluate the health effects of probiotics and other therapeutic modalities [48,[90][91][92][93][94][95][96][97][98] targeting bile acid deconjugation and metabolism.…”

Cholesterol homeostasis associated with probiotic supplementation in vivo

“…Several studies have shown that the drug therapeutics such as statin, the inhibitors of the 3-hydroxy-3-methylglutaryl coenzyme A reductase is essential in the cholesterol metabolic pathway, effectively to reduce the serum cholesterol (Guan et al 2017). However, it is not considered to be an optimal long-term solution due to their associated side effects such as muscle weakness, myalgia, reduced energy, deteriorating hyperglycaemia and increased risk of new-onset diabetes mellitus (Huang et al 2013;Saikia et al 2018).…”