Design, synthesis, and multitarget evaluation of thiosemicarbazone-sulfonamide hybrids as potent cholinesterase and MAO-A inhibitors with neuroblastoma-associated cytotoxicity

Neurodegenerative disorders and neuroblastoma represent major therapeutic challenges, and multitarget approaches have gained increasing attention. In this study, a series of thiosemicarbazone derivatives (5a-t) was evaluated for their inhibitory activity against acetylcholinesterase (AChE), butyrylcholinesterase (BChE), and Monoamine Oxidase A (MAO-A), together with their cytotoxic effects and molecular interaction profiles. In vitro enzyme assays revealed nanomolar inhibition for several compounds. Notably, compound 5n exhibited potent and balanced multitarget activity with IC₅₀ values of 104.28 nM (AChE), 23.04 nM (BChE), and 215.50 nM (MAO-A), surpassing galantamine (IC₅₀ = 296.32 and 105.20 nM for AChE and BChE, respectively) and approaching the activity of clorgyline (IC₅₀ = 401.68 nM). Kinetic studies confirmed strong enzyme binding, with K_i values of 92.42 nM (AChE) and 25.35 nM (BChE). Cytotoxicity assays against SH-SY5Y neuroblastoma cells showed selective antiproliferative effects, with compound 5n displaying an IC₅₀ of 5.23 µM and a selectivity index of 8.6 relative to HUVEC cells. Molecular docking and MM-GBSA analyses revealed strong binding affinities (docking scores - 10.4 to - 15.4 kcal/mol; ΔG_bind - 55.9 to - 88.4 kcal/mol), which were further supported by molecular dynamics simulations. DFT calculations indicated favorable electronic properties (HOMO-LUMO gap: 0.098-0.116 eV), while ADME predictions suggested acceptable drug-like behavior and good oral absorption. These results identify thiosemicarbazone derivative 5n as a promising multitarget lead for the development of agents targeting cholinergic dysfunction, MAO-A inhibition, and neuroblastoma proliferation.

Cholinesterase; Monoamine oxidase A; Neuroblastoma; Neurodegenerative disorders; Thiosemicarbazone.