Amphenicol and macrolide derived antibiotics inhibit paraoxonase enzyme activity in human serum and human hepatoma cells (HepG2) in vitro.

Human serum paraoxonase (hPON1) was separately purified by ammonium sulfate precipitation and hydrophobic interaction chromatography. The in vitro effects of commonly used antibiotics, namely clarithromycin and chloramphenicol, on purified human serum paraoxonase enzyme activity (serum hPON1) and human hepatoma (HepG2) cell paraoxonase enzyme activity (liver hPON1) were determined. Serum hPON1 and liver hPON1 were determined using paraoxon as a substrate and IC(50) values of these drugs exhibiting inhibition effects were found from graphs of hydratase activity (%) by plotting concentration of the drugs. We determined that chloramphenicol and clarithromycin were effective inhibitors of serum hPON1.