An efficient and promising method of treating complex neurodegenerative diseases like Alzheimer's disease (AD) is the multitarget-directed approach. Here in this work, a series of quinazoline derivatives (AV-1 to AV-21) were rationally designed, synthesized, and biologically evaluated as multitargeted directed ligands against human cholinesterase (hChE) and human β-secretase (hBACE-1) that exhibit moderate to good inhibitory effects. Compounds AV-1, AV-2, and AV-3 from the series demonstrated balanced and significant inhibition against these targets. These compounds also displayed excellent blood-brain barrier permeability via the PAMPA-BBB assay. Compound AV-2 significantly displaced propidium iodide (PI) from the acetylcholinesterase-peripheral anionic site (AChE-PAS) and was found to be non-neurotoxic at the maximum tested concentration (80 μM) against differentiated SH-SY5Y cell lines. Compound AV-2 also prevented AChE- and self-induced Aβ aggregation in the thioflavin T assay. Additionally, compound AV-2 significantly ameliorated scopolamine and Aβ-induced cognitive impairments in the in vivo behavioral Y-maze and Morris water maze studies, respectively. The ex vivo and biochemical analysis further revealed good hippocampal AChE inhibition and the antioxidant potential of the compound AV-2. Western blot and immunohistochemical (IHC) analysis of hippocampal brain revealed reduced Aβ, BACE-1, APP/Aβ, and Tau molecular protein expressions levels. The pharmacokinetic analysis of compound AV-2 demonstrated significant oral absorption with good bioavailability. The in silico molecular modeling studies of lead compound AV-2 moreover demonstrated a reasonable binding profile with AChE and BACE-1 enzymes and stable ligand-protein complexes throughout the 100 ns run. Compound AV-2 can be regarded as the lead candidate and could be explored more for AD therapy.
Keywords: Alzheimer’s disease; acetylcholinesterase; amyloid-β; multitargeting agents; β-secretase.