Green synthesis of Tacrine modified Schiff bases as anti-Alzheimer Agents: An effective strategy validated through in-silico and in-vitro analysis

A variety of Tacrine-modified Schiff base analogues were developed via solvent free (green) method and structurally elucidated using 1HNMR, FTIR and UV–Vis analysis. High product yield was obtained from the synthesised molecules, which were produced efficiently at room temperature without the need of a solvent. The developed molecules were subsequently assessed for their potential to inhibit acetylcholinesterase (AChE) and butyrylcholinesterase (BChE). These molecules revealed effective inhibition of AChE and BChE enzymes with IC₅₀ values varying from 0.1 ± 0.02 to 0.3 ± 0.03 μM and 0.065 ± 0.01 to 0.3 ± 0.03 μM respectively. Compared to the standard Tacrine which has IC₅₀ values of 0.35 ± 0.02 μM for AChE and 0.1 ± 0.01 μM for BChE. Notably, compound 3f showed strong inhibition among others for both the enzymes. The structure–activity relationship of derivatives synthesized were verified and established through molecular docking studies. Theoretical ADME studies also predicted excellent drug-likeness for all the synthesized molecules. Antioxidant activities were also assessed because elevated oxidative stress levels are linked with cognitive loss in Alzheimer's disease (AD). These findings suggest that the lead compound is potentially an effective inhibitor for the therapeutic management of AD.