Production of bioactive substances by intestinal bacteria as a basis for explaining probiotic mechanisms: Bacteriocins and conjugated linoleic acid

• Published in: International journal of food microbiology 2012-01, Vol.152 (3), p.189-205
• Main Authors: O'Shea, Eileen F., Cotter, Paul D., Stanton, Catherine, Ross, R. Paul, Hill, Colin
• Format: Article
• Language: English
• Subjects: adipose tissue; animal models; Animals; antimicrobial peptides; antimicrobial properties; Bacteria; Bacteriocin; bacteriocins; Bacteriocins - metabolism; Bifidobacterium; Bifidobacterium - metabolism; conjugated linoleic acid; Conjugated linoleic acid (CLA); fatty acid composition; Fatty Acids - metabolism; gastrointestinal system; Gastrointestinal tract (GIT); Gastrointestinal Tract - microbiology; health promotion; human health; Humans; intestinal microorganisms; Lactobacillus; Lactobacillus - metabolism; Linoleic Acids, Conjugated - metabolism; liver; Mice; Mice, Inbred BALB C; oral administration; pathogens; Pharmabiotic; probiotics; Probiotics - metabolism
• ISSN: 0168-1605; 1879-3460
• DOI: 10.1016/j.ijfoodmicro.2011.05.025

The mechanisms by which intestinal bacteria achieve their associated health benefits can be complex and multifaceted. In this respect, the diverse microbial composition of the human gastrointestinal tract (GIT) provides an almost unlimited potential source of bioactive substances (pharmabiotics) which can directly or indirectly affect human health. Bacteriocins and fatty acids are just two examples of pharmabiotic substances which may contribute to probiotic functionality within the mammalian GIT. Bacteriocin production is believed to confer producing strains with a competitive advantage within complex microbial environments as a consequence of their associated antimicrobial activity. This has the potential to enable the establishment and prevalence of producing strains as well as directly inhibiting pathogens within the GIT. Consequently, these antimicrobial peptides and the associated intestinal producing strains may be exploited to beneficially influence microbial populations. Intestinal bacteria are also known to produce a diverse array of health-promoting fatty acids. Indeed, certain strains of intestinal bifidobacteria have been shown to produce conjugated linoleic acid (CLA), a fatty acid which has been associated with a variety of systemic health-promoting effects. Recently, the ability to modulate the fatty acid composition of the liver and adipose tissue of the host upon oral administration of CLA-producing bifidobacteria and lactobacilli was demonstrated in a murine model. Importantly, this implies a potential therapeutic role for probiotics in the treatment of certain metabolic and immunoinflammatory disorders. Such examples serve to highlight the potential contribution of pharmabiotic production to probiotic functionality in relation to human health maintenance. ► We review the role of microbial-produced bioactive substances in probiosis. ► Bacteriocins can contribute to the ability of a strain to compete and establish itself in the gut. ► Bacteriocins may also protect against gastrointestinal pathogens in vivo. ► Probiotic bacteria can also play an important role in fatty acid metabolism.