Bifidobacterially produced, C18:3 and C18:4 conjugated fatty acids exhibit in vitro anti‐carcinogenic and anti‐microbial activity

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Conjugated fatty acid (CFA)s have shown a range of in vitro and in vivo bioactivities prompting increased endeavours both to identify novel sources and to characterize their properties. Strains of bifidobacteria possess the capacity to produce a range of CFAs including conjugated α‐linolenic acid (CLNA), conjugated γ‐linolenic acid (CGLA), and conjugated stearidonic acid (CSA), and in the current study these CFA were assessed for anti‐proliferative activity using the SW480 colon cancer cell line. Additionally, these fatty acids were also assessed for inhibitory activity against select gastro‐intestinal pathogens and potential probiotic CFA producers. The results demonstrated that the CFA displayed greater inhibitory activity against the SW480 cells than a normal fetal human colonic cell line (FHC), suggesting selective anti‐proliferative potential in vitro. Studies into the mechanism behind this inhibitory activity indicated potential roles for increased cellular lipid peroxidation, altered cellular phospholipid composition, and reductions in the cellular content of Bcl‐2. Microbiological studies also demonstrated that the CFA displayed inhibitory activity against selected pathogens, while CFA producing bifodobacteria remained unaffected. CFAs were particularly effective in the inhibition of the methicillin resistant strain Staphylococcus aureus ATCC 43300.Practical applications: We have demonstrated that bifidobacterially produced C18:3 and C18:4 CFAs may have potential in the control of colon cancer. Additionally, their inhibitory properties against common gastrointestinal pathogens (particularly the methicillin resistant strain S. aureus ATCC 43300) and not potential probiotic CFA producing bifidobacteria may indicate further therapeutic potential or a metabolic process that gives CFA producing microbes a competitive advantage in the complex environment that is the gastrointestinal tract.Strains of bifidobacteria such as Bifidobacterium breve DPC 6330 possess the capacity to bioconvert α‐linolenic, γ‐linolenic, and stearidonic acids to their conjugated derivatives under fermentative conditions. In vitro bioassays have indicated that these conjugated derivatives possess anti‐microbial activity, particularly against microbial pathogens including Staphyloccus aureus, and anti‐carcinogenic properties against colonic cancer cell lines such as SW480.