Cytotoxic Effects of Probiotic Bacteria Lactobacillus acidophilus and Lactobacillus rhamnosus Grown in the Presence of Oleuropein on Human Prostate Cancer Cells

Abstract

Functional foods are groups of foods that have potentially positive effects on health beyond basicnutrition. Probiotics are beneficial microorganisms, being as a group of functional foods, and wheningested in adequate amounts, they possess positive health effects to host organisms including havinganti-carcinogenic functions, yet their exact mechanisms how they possess anti-carcinogenic activitiesare still under investigation. Another group of functional foods is plant-based phenolic compounds.They also have potential to possess anti-carcinogenic activities. Among them, oleuropein is veryinteresting and well-known phenolic compound naturally present in olive fruits and olive oil. As thephenolic compounds and probiotic bacteria can be present at the same time in human gastrointestinaltract, this study aims to investigate the in vitro cytotoxic effects of Lactobacillus acidophilus LA-5 (LA5) and Lactobacillus rhamnosus GG (GG) grown in the presence of oleuropein on human prostatecancer cell line. For this, oleuropein was added to media of these bacteria and effects of cell-freesupernatants of these combinations (phenolic+probiotic) on cytotoxicity of prostate cancer cell line PC-3were investigated using MTT Method. Different concentrations of oleuropein were added to bacterialcultures and oleuropein added to the growth medium of LA-5 had additional effects on the cytotoxicityof cell-free supernatants of this bacterium. However, addition of oleuropein to the growth medium ofGG did not show significant changes on the cytotoxicity of cell-free supernatants of this bacterium.Thus, the results indicate that new combinations of functional foods have potential to formulate newnutraceuticals.