Cytotoxic effects of psychotropic benzofuran derivatives,N‐methyl‐5‐(2‐aminopropyl)benzofuran and its N‐demethylated derivative,on isolated rat hepatocytes

The novel psychoactive compounds derived from amphetamine have been illegally abused as recreational drugs, some of which are known to be hepatotoxic in humans and experimental animals. The cytotoxic effects and mechanisms of 5‐(2‐aminopropyl)benzofuran (5‐APB) and N‐methyl‐5‐(2‐aminopropyl)benzofuran (5‐MAPB), both of which are benzofuran analogues of amphetamine, and 3,4‐methylenedioxy‐N‐methamphetamine (MDMA) were studied in freshly isolated rat hepatocytes. 5‐MAPB caused not only concentration‐dependent (0–4.0 mm ) and time‐dependent (0–3 h) cell death accompanied by the depletion of cellular ATP and reduced glutathione and protein thiol levels, but also accumulation of oxidized glutathione. Of the other analogues examined at a concentration of 4 mm , 5‐MAPB/5‐APB‐induced cytotoxicity with the production of reactive oxygen species and loss of mitochondrial membrane potential was greater than that induced by MDMA. In isolated rat liver mitochondria, the benzofurans resulted in a greater increase in the rate of state 4 oxygen consumption than did MDMA, with a decrease in the rate of state 3 oxygen consumption. Furthermore, the benzofurans caused more of a rapid mitochondrial swelling dependent on the mitochondrial permeability transition than MDMA. 5‐MAPB at a weakly toxic level (1 mm ) was metabolized slowly: levels of 5‐MAPB and 5‐APB were approximately 0.9 mm and 50 μm , respectively, after 3 h incubation. Taken collectively, these results indicate that mitochondria are target organelles for the benzofuran analogues and MDMA, which elicit cytotoxicity through mitochondrial failure, and the onset of cytotoxicity may depend on the initial and/or residual concentrations of 5‐MAPB rather than on those of its metabolite 5‐APB. Copyright © 2016 John Wiley & Sons, Ltd.