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Graphical abstract Highlights • Novel p-aminobenzoic acid derivatives were designed, synthesized and characterized. • The compounds exhibited significant inhibitory potential against AChE and BChE. • Compound 22 exhibited significant improvements in working and reference memory. • The ex vivo study confirmed the ability of compound 22 to cross the BBB. • The in silico studies demonstrated the binding to active pocket in a stable manner. Abstract Based on the quantitative structure-activity relationship (QSAR), some novel p-aminobenzoic acid derivatives as promising cholinesterase enzyme inhibitors were designed, synthesized, characterized and evaluated to enhance learning and memory. The in vitro enzyme kinetic study of the synthesized compounds revealed the type of inhibition on the respective acetylcholinesterase (AChE) and butyrylcholinesterase (BChE) enzymes. The in vivo studies of the synthesized compounds exhibited significant reversal of cognitive deficits in the animal models of amnesia as compared to standard drug donepezil. Further, the ex vivo studies in the specific brain regions like the hippocampus, hypothalamus, and prefrontal cortex regions also exhibited AChE inhibition comparable to standard donepezil. The in silico molecular docking and dynamics simulations studies of the most potent compound 22 revealed the consensual interactions at the active site pocket of the AChE. [ABSTRACT FROM AUTHOR]

Abstract: Some new semicarbazones of 4-aminopyridine were synthesized and evaluated for antiamnesic, cognition enhancing and anticholinesterase activities. The results illustrated a significant cognition enhancing effect on elevated plus maze model with a significant reversal of scopolamine-induced amnesia. A significant inhibition in acetycholinesterase (AChE) activity by all the synthesized compounds in specific brain regions that is, prefrontal cortex, hippocampus and hypothalamus was observed. Compound 4APi exhibited significant antiamnesic and cognition enhancing activity which was comparable with standard drug donepezil. Its enzyme kinetic study revealed a non-competitive inhibition of AChE and a competitive inhibition of butyrylcholinesterase (BChE). Docking studies predicted the binding modes of these compounds in AChE active site, which were further processed for molecular dynamics simulation for calculating binding free energies using Molecular Mechanics–Generalized Born Surface Area (MM/GBSA). All the computational study confirmed their consensual interaction with AChE justifying the experimental outcome. [Copyright &y& Elsevier]

Graphical abstract Abstract Novel hybrids bearing a 2-aminopyrimidine (2-AP) moiety linked to substituted 1,3,4-oxadiazoles were designed, synthesized and biologically evaluated. Among the developed compounds, 28 noncompetitively inhibited human acetylcholinesterase (hAChE; pIC 50 = 6.52; Ki = 0.17 µM) and showed potential in vitro antioxidant activity (60.0%) when evaluated using the Ellman's and DPPH assays, respectively. Compound 28 competitively displaced propidium iodide (PI) from the peripheral anionic site (PAS) of hAChE (17.6%) and showed high blood-brain barrier (BBB) permeability, as observed in the PAMPA-BBB assay. Additionally, compound 28 inhibited hAChE-induced Aβ aggregation in a concentration-dependent manner according to the thioflavin T assay and was devoid of neurotoxic liability towards SH-SY5Y cell lines, as demonstrated by the MTT assay. The behavioral studies of compound 28 in mice showed a significant reversal of scopolamine-induced amnesia, as observed in Y-maze and passive avoidance tests. Furthermore, compound 28 exhibited significant AChE inhibition in the brain in ex vivo studies. An evaluation of oxidative stress biomarkers revealed the antioxidant potential of 28. Moreover, in silico molecular docking and dynamics simulation studies were used as a computational tool to evaluate the interactions of compound 28 with the active site residues of hAChE. [ABSTRACT FROM AUTHOR]

Graphical abstract Highlights • Biphenyl-3-oxo-1,2,4-triazine linked piperazines were designed and synthesized. • Compound 6g significantly inhibited the AChE and showed good CNS permeability. • In vivo studies showed significant improvement in learning and memory. • Biochemical analysis showed potential antioxidant property by compound 6g. Abstract A series of novel piperazine tethered biphenyl-3-oxo-1,2,4-triazine derivatives were designed, and synthesized. Amongst the synthesized analogs, compound 6g showed significant non-competitive inhibitory potential against acetylcholinesterase (AChE, IC 50 ; 0.2 ± 0.01 μM) compared to standard donepezil (AChE, IC 50 : 0.1 ± 0.002 μM). Compound 6g also exhibited significant displacement of propidium iodide from the peripheral anionic site (PAS) of AChE (22.22 ± 1.11%) and showed good CNS permeability in PAMPA-BBB assay (P e (exp) , 6.93 ± 0.46). The in vivo behavioral studies of compound 6g indicated significant improvement in cognitive dysfunctions against scopolamine-induced amnesia mouse models. Further, ex vivo studies showed a significant AChE inhibition and reversal of the scopolamine-induced oxidative stress by compound 6g. Moreover, molecular docking and dynamics simulations of compound 6g showed a consensual binding affinity and active site interactions with the PAS and active catalytic site (CAS) residues of AChE. [ABSTRACT FROM AUTHOR]

Some promising acetylcholinesterase (AChE) inhibitors with an antioxidant potential were designed, synthesised, and evaluated for their role in treating cognitive dysfunctions. The in silico Gaussian-based quantitative structureactivity relationship (QSAR), virtual screening (VS), QikProp drug-likeliness prediction and docking pose filtration protocols were adapted to design and screen the novel series of diaryl ether derivatives. Further, the selected compounds were investigated for their molecular binding stability using molecular dynamics (MD) simulation analysis and molecular mechanics generalised born surface area (MM-GBSA). The identified hits were synthesised and evaluated for their in vitro AChE inhibition and antioxidant potential. Among all the synthesized compounds, the compound 39 was observed as potent AChE inhibitor (AChE IC50 = 1.30 ± 0.09 μm; Ki = 0.054 ± 0.009 μM), and also the antioxidant potential of compound 39 (52.9%) was observed significantly better than standard donepezil (<10%) and parallel to ascorbic acid (56.6%). Further, compound 39 ameliorated the scopolamine-induced cognitive impairment in the Y-maze and passive avoidance testsin mice models. Ex vivo and biochemical analysis established the brain AChE inhibitory potential and antioxidant properties of compound 39. The results signified compound 39 to be a promising lead for the treatment of cognitive dysfunctions. [ABSTRACT FROM AUTHOR]