ATP AND PROTEIN-SYNTHESIS ASSAYS TO EVALUATE THE TOXICITIES OF PRESERVATIVES INVITRO

Cellular protein content, protein synthesis, ATP level and lactate dehydrogenase (LDH) activity, measured in a murine epidermal cell line (HEL/30), were used as the endpoints for determining the cytotoxicities of 17 antimicrobial chemicals. The relative toxicities of the test compounds were quantified by the determination of the concentrations inducing a 50% inhibition of [H-3]-leucine incorporation into proteins (IC50), causing a 50% reduction of ATP level or final cell protein content or producing the maximal effect on LDH leakage (EC50) after 2 hours of treatment. The results indicate a good correlation between both the reduction of ATP level and inhibition of protein synthesis and the minimal inhibitory concentration (MIC) on different microorganisms, suggesting that ATP and protein synthesis assays could be useful as prescreening methods for testing the cytotoxicities of preservatives.