Oxidative stress and structure-activity relationship in the zebrafish (Danio rerio) under exposure to paclobutrazol

The acute toxicity and changes in the activity of antioxidant enzymes including superoxide dismutase (SOD) and catalase (CAT) in the zebrafish Danio rerio were measured when the fish was exposed to paclobutrazol (PBZ) under laboratory conditions. The median lethal concentration value at 96 h post-exposure (LC(50) (96 h)) was determined to be 20.55 mg/L. In addition, the SOD activities in D. rerio were significantly higher at 96 h post-exposure among the various concentrations of the pollutant tested. The change of CAT activity could be considered as a sensitive biomarker of the oxidative stress induced by PBZ. The structure-activity relationship (SAR) analysis identified the potential active points for the pollutant and that the cavum may be the site of interaction with the receptor.