DESIGN, SYNTHESIS, AND BIOLOGICAL ASSESSMENT OF NOVEL N'-(BENZYLIDENE)PROPANEHYDRAZIDES AS MTDL FOR ALZHEIMER’S DISEASE

Abstract

Objective: In this study, following the multi-target directed ligands (MTDLs) strategy and drawing inspiration from the neuroprotective structure of ferulic acid, eight novel N'-(benzylidene)propanehydrazide derivatives were designed, synthesized, and tested to evaluate their cholinesterase inhibitory and antioxidant capacities. Material and Method: To obtain the final compounds, first, corresponding key intermediates, 3-(substitutedamino)propanehydrazides, were prepared by the hydrolysis with hydrazine hydrate of methyl 3-(substitutedamino)propanoate intermediates. These intermediates had been prepared from the Michael addition of methyl acrylate and commercially available tertiary amine derivatives. Subsequently, the final compounds were synthesized from the reaction of the starting compounds 4-hydroxybenzaldehyde or 4-methoxybenzaldehyde and the corresponding key intermediates. Structural analysis of the synthesized and purified compounds was carried out using 1H-NMR, 13C-NMR, and HRMS. Then, all the final compounds were examined for their cholinesterase inhibitory effect using the modified Ellman method, their antioxidant effect using the DPPH and ORAC methods, and their metal chelator effect using UV-spectroscopy analysis. Moreover, physicochemical parameters were calculated using QikProp Schrödinger Suite 2023 to predict the druggability of all compounds. Result and Discussion: Seven of the eight final compounds exhibited moderate cholinesterase inhibition at varying rates. Compounds 2a (IC50 = 12.83 µM) and 2d (IC50 = 16.02 µM) were identified as the most potent inhibitors for acetylcholinesterase (AChE) and butyrylcholinesterase (BChE), respectively. Moreover, all the final compounds exhibited antioxidant activity in the ORAC assay. Chelator effects of all compounds were also observed for Cu(II), Fe(II), and Zn(II) ions at varying rates. Additionally, the final compounds demonstrated acceptable lead-like properties according to in-silico predictions.