Determination of anti biofilm and anti quorum sensing activities of expolysaccharides obtained from vaginal derived lactobacillus strains

Exopolysaccharides (EPSs) are biopolymers commonly found in plants, fungi and bacteria in nature and have the potential to contribute to human health due to their antimicrobial, anti-biofilm, antioxidant, antitumor, antiviral and immunomodulatory activity. In our study, five strains (L. paracasei L1, L. casei L2, L. pantarum L4, L. crispatus L5 and L. rhamnosus L17) were selected among the lactic acid bacteria (LAB) with proven probiotic properties that were previously isolated from vaginal microflora. . Antimicrobial, antibiofilm, anti-quarum sensing, antioxidant activities and anti-proliferative effects on MDA-MB-231 breast cancer cell line cells of EPSs obtained from pure strains were investigated. In our study, FT-IR and GC-MS analyzes of pure EPS were also performed and electron microscope images were obtained. As a result of the study, it was determined that LAB-derived EPSs have strong antimicrobial activity, and the strain with the strongest antimicrobial activity among xi pathogenic strains was EPS belonging to L. casei L2 strain. E. coli and P. aeruginosa strains were used to determine the anti-biofilm activity of pure EPS extracts. As a result of the study, it is seen that EPSs have an inhibitory effect at different concentrations, and EPSs obtained from L1 and L2 strains have stronger activity. In the study investigating the anti-quarum sensing activities of pure EPS at different concentrations, it was determined that while each EPS showed an average equal activity at a concentration of 10 mg/mL, the effect increased at a concentration of 20 mg/mL and the rate of effect varied. The anti-proliferative effect of pure EPS on MDA-MB-231 breast cancer cell line cells was observed at the highest dose of 115 μg/ml of EPS of L. paracasei L1 strain, while 90-95% mortality was observed in L. casei L2 strain. At the highest dose of 85 μg/ml of EPSs, approximately 100% mortality was observed. It is noteworthy that EPSs, which have different beneficial effects on human health, have natural antimicrobial and anticancer properties. However, more research is needed in this area so that it can be used in the treatment of both infections and various cancers in the future