Butylone enantioseparation and ecotoxicity evaluation on Daphnia magna

Abstract

Background: The synthetic drug butylone (2-methylamino-1-(3,4-methylenedioxyphenyl)butan-1-one, BTL) is a chiral cathinone consumed in the form of racemate [1]. After consumption, BTL is metabolized and excreted along with its metabolites, and its residues are carried by sewerage systems to wastewater treatment plants (WWTPs) [2]. Both human metabolism and biodegradation in WWTPs may be enantioselective causing a change in its enantiomeric fraction (EF). However, enantiomers may exhibit different biological activities including toxicity on non-target aquatic organisms [3]. Objective: This study aimed to separate both enantiomers and assess the sub-chronic effects on Daphnia magna focusing on morphophysiological and reproductive parameters. Methods: The enantiomers were separated by liquid chromatography using a homemade semipreparative chiral column (APS-Nucleosil coated with a 3,5-dimethylphenylcarbamate of amylose). Daphnia (with less than 24 h) were exposed for 9 days to concentrations of 0.1, 1, 10 μg/L, with a total of 5 replicates per concentration and a control.  Results: Morphophysiological alterations were observed, except in the heart area. A tendency to the increase of body size, heart size and mortality were observed for the higher concentrations (1 and 10 μ/L). The daphniids with eggs tended to decrease. Analysis of other endpoints (ongoing) are required to draw accurate conclusions. Conclusions: The present study demonstrates that exposure to BTL may cause effects on mortality and morphology of D. magna. The ongoing studies will bring new knowledge on BTL adverse effects and the possible enantioselective toxicity effects on this non-target aquatic organism.