Probiotic and functional characterization of newly isolated Lactiplantibacillus plantarum strains from human breast milk and proliferative inhibition potential of metabolites

Four Lactiplantibacillus plantarum strains newly isolated and identified from human breast milk in Türkiye, have probiotic, functional and proliferative inhibition potential of metabolites against colon cancer cell lines were evaluated. In simulated gastric and intestinal media, all strains exhibited strong probiotic character by showing resistance, although decreasing with time and concentration. The strains were sensitive to penicillin G, rifampin and chloramphenicol and showed antibacterial effect on all pathogenic bacteria. Citric acid, malic acid, tartaric acid, pyruvic acid and fumaric acid were not detected in the strains, while the highest amount of acetic acid was detected. The quantitative-qualitative analysis and structural characterization of exopolysaccharide (EPS) was confirmed and it was determined that the strains synthesized similar amounts. Compared to standard antioxidants, the strains showed less DPPH activity and similar ABTS activity. High amounts of metabolites of the strains showed good antiproliferative effect on Caco-2, while lower amounts showed good antiproliferative effect on the HT-29 cell line. When all the data were considered, it was determined that the strains were close to each other, but the YAAS 23 strain showed slightly better properties. In conclusion, breast milk is a unique environment harboring beneficial bacteria such as L. plantarum for human health.