4′-Fluoropyrrolidinononanophenone elicits neuronal cell apoptosis through elevating production of reactive oxygen and nitrogen species

Purpose alpha-Pyrrolidinononanophenone (alpha-PNP) is a highly lipophilic synthetic cathinone (SC) that possesses a long hydrocarbon chain. It is considered that abuse of alpha-PNP and its derivatives causes serious health hazards, but there has been little evidence to date on the toxicological, pharmacological and pharmacokinetic properties. The purpose of this study was to elucidate the structure-toxicity relationship and the mechanism of neurocytotoxicity of alpha-PNP derivatives. Methods We synthesized three alpha-PNP derivatives [4 '-fluoro, 4 '-methoxy and 3 ',4 '-methylenedioxy substituents on the aromatic ring] and examined their toxicities against four human cells. The mechanism of 4 '-fluoro-alpha-PNP (F-alpha-PNP)-induced neurocytotoxicity was investigated in terms of productions of reactive oxygen species (ROS) and reactive nitrogen species (RNS). Results Cytotoxicites of alpha-PNP derivatives were augmented by the presence of 4 '-fluoro or 3 ',4 '-methylenedioxy group on alpha-PNP, and F-alpha-PNP exhibited the most potent cytotoxicity. The F-alpha-PNP treatment resulted in ROS production, cytochrome-crelease into cytosol, caspase-9 and caspase-3 activation and DNA fragmentation in neuronal SK-N-SH cells. In addition, subcellular fractionation analysis demonstrated that F-alpha-PNP is localized in the mitochondria as early as 12 h after the incubation. alpha-PNP derivatives increased level of nitric oxide (NO) and 3-nitrotyrosine adducts, indicative of peroxynitrite formation, in SK-N-SH cells. Pretreatment with a NO or peroxynitrite donor also exacerbated the cellular toxicity of F-alpha-PNP. Conclusion The presence of 4 '-fluoro or 3 ',4 '-methylenedioxy group in the aromatic ring on SCs likely elevates the risk of occurrence of health hazards. Additionally, enhanced production of ROS and RNS plays central roles in neuronal cell apoptotic mechanism of F-alpha-PNP.

Automated summary

The study aimed to investigate the toxicity of alpha-PNP derivatives on human cells and explore the mechanism of neurocytotoxicity. The presence of 4'-fluoro or 3',4'- methylenedioxy group on alpha-PNP enhances the cytotoxicity of the derivatives, with 4'-fluoro-alpha-PNP displaying the most potent toxicity.