Cholesterol-lowering effects of a putative probiotic strain Lactobacillus plantarum EM isolated from kimchi
Introduction
Lactic acid bacteria (LAB) are industrially important microorganisms worldwide for the fermentation of foods. Moreover, LAB as probiotics have become the focus of intensive international research for their health-promotion effects, which include reduction of serum cholesterol level, stimulation of immune responses, cancer prevention, and alleviation of diarrhea (De Vrese & Schrezenmeir, 2008). The numerous health benefits of LAB have made them into promising probiotic candidates that are studied for their desirable properties. The World Health Organization (WHO) has predicted that cardiovascular disease will remain the leading cause of death through 2030, affecting approximately 23.6 million people worldwide (WHO, 2009). Increased serum cholesterol correlates highly with coronary heart disease (Kumar et al., 2012). Thus, investigators are paying close attention to the cholesterol-lowering effects of LAB among their many functional effects.
Studies have indicated that several LAB strains, mainly Lactobacillus spp., have cholesterol-reducing effects in vitro or in vivo (Kumar et al., 2012, Ooi and Liong, 2010). However, the exact mechanisms of serum cholesterol reduction by probiotic bacteria are not completely clear. Several mechanisms have been proposed in vitro, including assimilation (Pereira & Gibson, 2002), surface binding (Liong & Shah, 2005), incorporation into cellular membranes (Lye, Rusul, & Liong, 2010a), co-precipitation with deconjugated bile (Liong & Shah, 2006), enzymatic deconjugation of bile acids by bile salt hydrolase (BSH) (Lambert, Bongers, de Vos, & Kleerebezem, 2008), conversion of cholesterol into coprostanol (Lye, Rusul, & Liong, 2010b), and production of short-chain fatty acids by probiotics (De Preter et al., 2007).
The aim of this study was to investigate high cholesterol removal by dead cells of the selected LAB strain as well as its possible mechanisms of action. Moreover, the selected strain was identified and evaluated in terms of its probiotic properties, such as acid and bile tolerance, antimicrobial activity against pathogens, and antibiotic resistance.
Section snippets
Bacterial cultures and screening of LAB strains for cholesterol removal
Screening of LAB strains from kimchi for cholesterol removal was carried out by determination of BSH activity (Dashkevicz & Feighner, 1989) and cholesterol assimilation (Rudel & Morris, 1973).
Isolation and identification of cholesterol-lowering LAB
Seventy LAB cultures were isolated from 28 kimchi samples collected from 17 cities in South Korea. All isolates were grown well at 30 °C in MRS medium. However, only 50 LAB strains among the 70 total LAB strains could be grown at 37 °C. These 50 LAB strains were preselected for further experimentation. BSH activity and cholesterol assimilation of the 50 preselected LAB strains were examined (Table 1). Of the 50 tested LAB strains, 16 LAB strains expressed BSH activity, and their cholesterol
Conclusions
As the term probiotics means “for life”, viable probiotics are required to have beneficial effects on their host. In this study, L. plantarum EM showed high cholesterol removal by growing, resting, and even dead cells based on the high cholesterol-binding capacity of its cell wall fraction. Therefore, L. plantarum EM could be a potent probiotic to reduce serum cholesterol regardless of its viability. Moreover, L. plantarum EM also appeared to meet the functional criteria required for beneficial
Acknowledgment
This research was supported by High Value-added Food Technology Development Program, Ministry of Agriculture, Food and Rural Affairs, South Korea.
References (34)
- et al.
Antibacterial activity of lactic acid bacteria against spoilage and pathogenic bacteria isolated from the same meat small-scale facility 1-Screening and characterization of the antibacterial compounds
Food Control
(2006) - et al.
The interaction between bacteria and bile
FEMS Microbiology Reviews
(2005) - et al.
Biological preservation of food with reference to protective cultures, bacteriocins and food-grade enzymes
International Journal of Food Microbiology
(1995) - et al.
Viability loss and morphology change of foodborne pathogens following exposure to hydrostatic pressures in the presence and absence of bacteriocin
International Journal of Food Microbiology
(2004) - et al.
Acid and bile tolerance and cholesterol removal ability of Lactobacilli strains
Journal of Dairy Science
(2005) - et al.
Effects of a Lactobacillus casei synbiotic on serum lipoprotein, intestinal microflora, and organic acids in rats
Journal of Dairy Science
(2006) - et al.
Mechanisms of cholesterol removal by lactobacilli under conditions that mimic the human gastrointestinal tract
International Dairy Journal
(2010) - et al.
Removal of cholesterol by Lactobacilli via incorporation of and conversion to coprostanol
Journal of Dairy Science
(2010) - et al.
Incorporation of cholesterol into the cellular membrane of Lactobacillus acidophilus ATCC 43121
Journal of Dairy Science
(1997) - et al.
Determination of cholesterol using O-phthalaldehyde
Journal of Lipid Research
(1973)
Probiotic bacteria: safety, functional and technological properties
Journal of Biotechnology
Viability of Lactobacillus gasseri and its cholesterol-binding antimutagenic activities during subsequent refrigerated storage in nonfermented milk
Journal of Dairy Science
Development of a differential medium for bile salt hydrolase-active Lactobacillus spp
Applied and Environmental Microbiology
Effects of Lactobacillus casei shirota, Bifidobacterium breve, and oligofructose-enriched inulin on colonic nitrogen-protein metabolism in healthy humans
American Journal of Physiology – Gastrointestinal and Liver Physiology
Probiotics, prebiotics, and synbiotics
Advances in Biochemical Engineering Biotechnology
Guidance on the assessment of bacterial susceptibility to antimicrobials of human or veterinary importance
EPSA Journal
Dual effects of Lactobacilli as a cholesterol assimilator and an inhibitor of gastrointestinal pathogenic bacteria
International Journal of Enteric Pathogens
Cited by (118)
Functional butter for reduction of consumption risk and improvement of nutrition
2023, Grain and Oil Science and TechnologyMonitoring the fatty acids profile and biogenic amines content in salted grey mullet (Fessiekh) fermented by lactic acid bacteria
2022, Egyptian Journal of Aquatic ResearchUtilization of autochthonous lactic acid bacteria attaining safety attributes, probiotic properties, and hypocholesterolemic potential in the production of a functional set yogurt
2022, Biocatalysis and Agricultural Biotechnology