Determination of DNA-bioprotetive properties of some industrial important lactic acid bacteria

In this study, an indigenous L. plantarum and the reference L. rhamnosus NRRL B-442 strains which have probiotic properties and used as starter culture in the food industry, were subjected to research for their aflatoxin B1 (AFB1) and polycyclic aromatic hydrocarbons (PAH), which are typical food contaminants, in terms of time dependant binding properties. The efficacy of binding was determined with high performance liquid chromatography (HPLC). DNA-bioprotective properties of lactic acid bacteria against AFB1 and PAH's was showed as in vitro using HT-29 human colon adenocarcinoma cell line with comet assay. Apoptotic effects of lactic acid bacteria, AFB1 and PAH's were confirmed both flow cytometer and acridine orange-ethidium bromide dye assay. According to the research findings; the highest retention of AFB1 by L. plantarum was 75,93±3,42% at 12th hour. Due to the most carcinogenic compound of PAH mixture was benzo[a]pyrene (B[a]P) was specified as indicator compound. So the time for the highest binding of B[a]P by L. plantarum was chosen for the optimum time. The optimum time for binding B[a]P by L. plantarum at the rate 100% a was assigned as the beginning of the mixture at 0th hour. Inactivation of AFB1 by L. thamnosus NRRL B-442 was optimum at the time of zero when AFB1-L. rhamnosus were mixed at the rate of 78,10±7,24%; similarly PAH mixture as B[a]P was binded 100% at 0th hour. No genotoxic effects were observed in HT-29 cells by L. plantarum and L. rhamnosus NRRL B-442, but they avoided the genotoxic damage statistically important manner induced by AFB1 and PAH mixture. Also used toxins and lactic acid bacteria showed apoptotic effect on human colon adenocarcinoma cell line HT-29 and determined by acridine orange-ethidium bromide tandem dye assay using laser scanning confocal microscope and by Annexin V-FITC-propidium iodide apoptosis assay at flow cytometry.