Cathinone derivatives are the most representative group within new drugs market, which have been described as neurotoxic. Since cathinones, as pentedrone and methylone, are available as racemates, it is our aim to study the neuronal cytotoxicity induced by each enantiomer. Therefore, a dopaminergic SH-SY5Y cell line was used to evaluate the hypothesis of enantioselectivity of pentedrone and methylone enantiomers on cytotoxicity, oxidative stress, and membrane efflux transport (confirmed by in silico studies). Our study demonstrated enantioselectivity of these cathinones, being the S-(+)-pentedrone and R-(+)-methylone the most oxidative enantiomers and also the most cytotoxic, suggesting the oxidative stress as main cytotoxic mechanism, as previously described in in vitro studies. Additionally, the efflux transporter multidrug resistance associated protein 1 (MRP1) seems to play, together with GSH, a selective protective role against the cytotoxicity induced by R-(-)-pentedrone enantiomer. It was also observed an enantioselectivity in the binding to P-glycoprotein (P-gp), another efflux protein, being the R-(-)-pentedrone and S-(-)-methylone the most transported enantiomeric compounds. These results were confirmed, in silico, by docking studies, revealing that R-(-)-pentedrone is the enantiomer with highest affinity to MRP1 and S-(-)-methylone and R-(-)-pentedrone are the enantiomers with highest affinity to P-gp. In conclusion, our data demonstrated that pentedrone and methylone present enantioselectivity in their cytotoxicity, which seems to involve different oxidative reactivity as well as different affinity to the P-gp and MRP1 that together with GSH play a protective role.
Keywords: ABC transporters; Dopaminergic SH-SY5Y; Enantioselectivity; Oxidative stress; Pentedrone and methylone enantiomers.
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