Microwave-assisted green synthesis and biological evaluation of a novel isatin-thiazole-benzofuran hybrid with dual acetylcholinesterase inhibitory and antioxidant activities

The development of sustainable strategies for the synthesis of biologically active molecules remains a central goal in medicinal chemistry. Herein, we describe a novel isatin-thiazole-benzofuran hybrid synthesized via a microwave-assisted green approach and evaluated as a promising lead scaffold with dual AChE inhibitory and antioxidant activities. The target compound was efficiently synthesized under mild conditions using an eco-friendly solvent system and a simplified work-up procedure, resulting in reduced energy consumption and waste generation. The synthesized hybrid was evaluated for its inhibitory activity against AChE and butyrylcholinesterase (BChE) using Ellman's method, displaying micromolar AChE inhibition with noticeable selectivity over BChE. Kinetic analysis indicated a mixed-type mode of inhibition, providing mechanistic insight into enzyme interaction. Docking results were consistent with the observed inhibitory activity, revealing stable binding within the AChE active site through π-π stacking interactions with key residues at both the catalytic active site (CAS) and the peripheral anionic site (PAS) together with favorable hydrogen-bonding interactions. In addition, the compound exhibited significant antioxidant activity in the DPPH radical scavenging assay (IC₅₀ = 10.01 ± 0.49 μg/mL), comparable to that of ascorbic acid (IC₅₀ = 10.22 ± 0.74 μg/mL). Collectively, these results highlight the isatin-thiazole-benzofuran framework as a promising lead scaffold that integrates green synthetic accessibility with dual anticholinesterase and antioxidant properties, warranting further structural optimization for Alzheimer's disease-related applications.