Isovanillin-derived bis-hydrazones as dual cholinesterase and carbonic anhydrase inhibitors: synthesis, enzymatic profiling, and computational insights from molecular docking and dynamics

Aims: To develop isovanillin-based bis-hydrazones as multitarget inhibitors of acetylcholinesterase (AChE), butyrylcholinesterase (BChE), and human carbonic anhydrase I/II (hCA I/II). Materials & methods: Twelve bis-hydrazones (4a–4l) were synthesized in two steps and evaluated by spectrophotometric enzyme assays, Lineweaver–Burk kinetics, molecular docking, MM-GBSA, molecular dynamics simulations, and in silico ADME/Tox profiling. Results: All compounds showed nanomolar inhibition. Compound 4d was the most potent AChE/BChE inhibitor (K_I = 10.46 and 3.56 nM), while 4a and 4j led the hCA I/II panel (K_I = 3.46 and 16.12 nM). Docking, MM-GBSA, and molecular dynamics supported dual-site cholinesterase engagement and non-zinc, peripherally anchored hCA inhibition. Conclusions: Isovanillin-based bis-hydrazones, particularly 4d, 4a, and 4j, represent promising multitarget leads for cholinergic and hCA-linked disorders.