Cytoxic and apoptotic effects of lyophylized postbiotics from colostrum

Cancer is one of the important health problems that occur as a result of dysbiosis in the microbiota. Colorectal cancer is the third leading cause of cancer incidence, with an estimated 1,000,000 new cases worldwide each year and a significant death rate of approximately 33% in the developed world. Bovine colostrum (SK) has begun to attract the attention of researchers day by day due to its anticancer potential. SK is rich in lactoferrin, a glycoprotein with powerful antioxidant, anti-inflammatory, anti-cancer and anti-microbial properties. Colostrum also contains a wide variety of probiotic bacteria. Within the scope of this thesis; Identification, autoaggregation and coaggregation, biofilm formation, antibiotic susceptibility, antimicrobial activity, lactic acid production, hemolytic activities, pH, salt, bile salt and acid resistance of lactic acid bacteria isolated from colostrum fermented for 21 days were determined by classical and molecular methods. On the Caco-2 cell line, cytotoxic effects with MTT method and apoptotic effects with Annexin V-PI method were investigated using lyophilized postbiotics. Five species that stand out in terms of biological activity have been identified as Lacticaseibacillus rhamnosus. IC50 values were found to be between 8.657 and 15.520 mg/mL. In the studies performed in flow cytometry; lyophilized postbiotics have been found to cause late apoptosis. The fact that postbiotics do not contain live microorganisms compared to probiotics, contain soluble bacterial metabolites, have superior properties such as storage conditions and durability, reveals the potential to be used for health benefits in terms of food, cosmetics and supplements in the future. Keywords: Colorectal cancer, colostrum, probiotic, flow cytometry.