Reference Number: 505
Year: 2019
Link: Link to original paper
Health: Cancer | Gut Microbiome - Creating Healthier Bread to Support Optimal Gut Health | Immune response
Nutrition: Fibre | Postbiotic | Probiotic
Lactic Acid Bacteria: Homofermentative | Prevalence
Yeast: Species
Summary
Background
Lactobacillus plantarum, a major species of Lactic Acid Bacteria (LAB), are capable of producing postbiotic metabolites (PM) with prominent probiotic effects that have been documented extensively for rats, poultry and pigs. Despite the emerging evidence of anticancer properties of LAB, very limited information is available on cytotoxic and antiproliferative activity of PM produced by L. plantarum. Therefore, the cytotoxicity of PM produced by six strains of L. plantarum on various cancer and normal cells are yet to be evaluated.
Methods
Postbiotic metabolites (PM) produced by six strains of L. plantarum were determined for their antiproliferative and cytotoxic effects on normal human primary cells, breast, colorectal, cervical, liver and leukemia cancer cell lines via MTT assay, trypan blue exclusion method and BrdU assay. The toxicity of PM was determined for human and various animal red blood cells via haemolytic assay. The cytotoxicity mode was subsequently determined for selected UL4 PM on MCF-7 cells due to its pronounced cytotoxic effect by fluorescent microscopic observation using AO/PI dye reagents and flow cytometric analyses.
Results
UL4 PM exhibited the lowest IC50 value on MCF-7, RG14 PM on HT29 and RG11 and RI11 PM on HL60 cell lines, respectively from MTT assay. Moreover, all tested PM did not cause haemolysis of human, dog, rabbit and chicken red blood cells and demonstrated no cytotoxicity on normal breast MCF-10A cells and primary cultured cells including human peripheral blood mononuclear cells, mice splenocytes and thymocytes. Antiproliferation of MCF-7 and HT-29 cells was potently induced by UL4 and RG 14?PM respectively after 72?h of incubation at the concentration of 30% (v/v). Fluorescent microscopic observation and flow cytometric analyses showed that the pronounced cytotoxic effect of UL4 PM on MCF-7 cells was mediated through apoptosis.
Conclusion
In conclusion, PM produced by the six strains of L. plantarum exhibited selective cytotoxic via antiproliferative effect and induction of apoptosis against malignant cancer cells in a strain-specific and cancer cell type-specific manner whilst sparing the normal cells. This reveals the vast potentials of PM from L. plantarum as functional supplement and as an adjunctive treatment for cancer.
Significance of this study to the baker:
This study details how these novel ‘postbiotics’ from the lactic acid bacteria (LAB) may help prevent the growth of cancer cells. Postbiotics are the waste products or by-products of fermentation that occurs within our gut between dietary prebiotics (such as fibre) and the beneficial probiotic bacteria that reside within our gut. Here at the sourdough school, we believe in our 7 core principles, where if we increase consumption of dietary fibre, ensure dietary diversity and even add such strain specific probiotics to our bakes (such as LGG) then studies like this suggest we can truly nourish our gut and improve our health.
