Purpose: The aim of this study was to analyze the cytotoxicity of partially purified bacteriocins produced by six bacterial strains, obtained from goat milk.
Methods: Bacteriocins produced by Lactococcus lactis subsp. lactis (GLc03 and GLc05) and Enterococcus durans (GEn09, GEn12, GEn14 and GEn17) were partially purified from 12-h cultures grown in MRS broth at 37oC by precipitation with ammonium sulfate and hydrophobic chromatography on SepPakC18. Vero cells derived from monkey kidney were seeded in 96-well plate and subsequently treated with increasing concentrations of studied bacteriocins. Two days after initial treatment, MTT was added to cells and colorimetric intensity was obtained at wavelength of 490 nm. The obtained values were converted into percentage of viability, and compared to negative control.
Results: The tested bacteriocin concentrations, ranged from 6 µg/ml to 480 µg/ml, showed different levels of cytotoxicity. The lowest cytotoxicity values were 172 μg/ml and 295 µg/ml, corresponding to the bacteriocins produced by E. durans GEn09 and L. lactis subsp. lactis GLc03, respectively. The cell line viability remained higher than 80% when treated with maximum concentrations of the bacteriocins produced by other tested strains (GLc05, GEn12, GEn14 and GEn17) and therefore it was not possible to estimate the value CC50. All strains showed cell viability above 80% when tested at concentration of 6 µg/ml.
Significance: Obtained results indicated low cytotoxicity of the tested bacteriocins, indicating that these peptides can be considered as safe and highlighting their potential use as biopreservatives in food. Acknowledgments: CAPES, CNPq and FAPEMIG.