Synthetic cannabidiol analogues exhibit lower toxicity than cannabidiol and protect against ethanol-induced apoptosis in SH-SY5Y cells

Cannabidiol (CBD) shows therapeutic potential for treating alcohol use disorder (AUD); however, its neurotoxicological profile remains insufficiently characterized, especially when compared with emerging synthetic analogues designed to improve safety. This study compares the neurotoxic and mechanistic profiles of CBD and two synthetic derivatives, PQM-242 and PQM-249, and evaluates their ability to attenuate ethanol-induced cellular injury. Human SH-SY5Y neuroblastoma cells were exposed to increasing concentrations (0.1-1000 µM) to generate concentration-response curves, estimate no-observed-adverse-effect levels (NOAELs), and determine cytotoxicity thresholds. Cell viability (MTT), apoptosis (annexin V/propidium iodide), and Bax and Bcl-2 expression (western blot) were assessed after 48 h of exposure. CBD showed an LC50 of 44 µM, whereas PQM-242 and PQM-249 displayed LC50 values > 600 µM, indicating markedly lower intrinsic toxicity in the proposed study model. The NOAELs for PQM-242 and PQM-249 were 100 µM, compared with 10 µM for CBD. For co-exposure studies, 10 µM was selected to enable direct comparison under ethanol challenge (250 mM). All compounds reduced ethanol-induced loss of viability and apoptosis, and PQM-242 additionally prevented ethanol-mediated Bax upregulation. Overall, PQM-242 and PQM-249 demonstrated enhanced cellular safety and maintained protective activity, supporting their further investigation as candidate molecules for AUD.