Synthesis, characterization, in vitro cholinesterase and hRBCs hemolysis assay and computational evaluation of novel 2,3,4,5-tetrahydrobenzothiazepine appended α-aminophosphonates

Synthesis and anti-Alzheimer potential of novel α-amino phosphonate derivatives and probing their molecular interaction mechanism with acetylcholinesterase

Pleiotropic interference may be a prerequisite for the efficient limitation of the progression of multi-factorial diseases such as Alzheimer's disease (AD). Concept of designing the single chemical entity acting on two or more targets of interest has potential advantage in AD therapy. In line with this, rational design and synthesis of frame work of hybrids bearing 2,3-disubstituted quinazolinone, vanillin and α-amino phosphonate scaffolds (5a─v) were carried out. A congeneric set of twenty-two synthetic derivatives (5a─v) were evaluated for their cholinesterase inhibitory, antioxidant, DNA nicking, DNA protection, neuroprotective and Aβ aggregation modulatory activities. Amongst tested activities, the most significant and worth mentioning is that the analogues 5m, 5p and 5u were found to be the most potent, selective, and mixed type inhibitors of EeAChE with IC₅₀ values of 0.296 ± 0.030, 0.289 ± 0.027, and 0.306 ± 0.028 μM, respectively. Further, the biophysical approaches indicated that the compounds 5m, 5p, and 5u have a strong binding affinity towards AChE. Kinetic and Molecular docking studies have revealed that the most active congeners were well oriented in the AChE active site by interacting with both catalytic active site (CAS) and peripheral anionic site (PAS). A few parameters derived from molecular dynamics (MD) simulation trajectories emphasized the stability of AChE-5p and 5m complexes throughout the 100 ns simulations, and the local conformational changes of the residues of AChE validate the stability of AChE-5p and 5m complexes. Further, these derivatives significantly impacted ABTS radical scavenging capacities and maximal DNA protection activity. Importantly, Thioflavin T (ThT) assay and FE-SEM study demonstrated compounds 5m, 5p and 5u as effective Aβ_1-42 fibril modulators at molecular level by the formation of micro size co-assembled mature structures, thus efficiently abolishing the cytotoxicity of Aβ_1-42. Finally, these active compounds are determined to be non-toxic and highly neuroprotective against H₂O₂-induced cell death in SK-N-SH cell lines. Furthermore, in silico ADMET prediction studies have revealed that the targeted analogues satisfied most of the characteristics of CNS acting drugs. These multi-functional efficacies indicated worthiness of these α-amino phosphonate derivatives being chosen for further pharmacokinetics, toxicity, and behavioral research to test their potential for AD treatment.

Synthesis and Biological Studies of Novel Aminophosphonates and Their Metal Carbonyl Complexes (Fe, Ru)

The quest to find new inhibitors of biologically relevant targets is considered an important strategy to introduce new drug candidates for the treatment of neurodegenerative diseases. A series of (aminomethyl)benzylphosphonates 8a–c and their metallocarbonyl iron 9a–c and ruthenium 10a–c complexes were designed, synthesized, and evaluated for their inhibitory potentials against acetylcholinesterase (AChE) and butyrylcholinesterase (BuChE) by determination of IC₅₀. Metallocarbonyl derivatives, in general, did not show significant inhibition activity against these enzymes, the most potent inhibitor was the (aminomethyl)benzylphosphonate 8a (IC₅₀ = 1.215 µM against AChE). Molecular docking analysis of AChE and (aminomethyl)benzylphosphonates 8a–c showed the strongest interactions of 8a and AChE compared to isomers 8b and 8c. Cytotoxicity studies of synthesized compounds towards the V79 cell line were also performed and discussed.

Synthesis, characterization, molecular docking, dynamics simulations, and in silico absorption, distribution, metabolism, and excretion (ADME) studies of new thiazolylhydrazone derivatives as butyrylcholinesterase inhibitors

In this study, two novel series of thiazolylhydrazone derivatives containing 4-ethylpiperazine (3a–3f) and 4-methoxyphenylpiperazine (3g–3l) side chains were synthesized and their structures were characterized by spectral (1H NMR, 13C NMR, and MS spectra) analyses. In vitro inhibitory activities of synthesized compounds against acetylcholinesterase (AChE) and butyrylcholinesterase (BChE) were determined by Ellman method. According to the results, all compounds showed a weak inhibitory effect on AChE, while promising results were obtained on BChE. Among the synthesized compounds, the activities of the derivatives carrying 4-ethylpiperazine (3a–3f) structure were found to be more effective than the compounds carrying 4-methoxyphenyl piperazine (3g–3l) derivatives. Especially, compound 3f bearing the nitro substituent was found to be the most promising compound on BChE in the series. The absorption, distribution, metabolism, and excretion (ADME) parameters of the synthesized compounds were predicted by using the SwissADME server. The potential binding mode and stability of compound 3f with BChE were investigated by the molecular docking and dynamics simulations. The results showed that 3f was strongly bound up with BChE with the optimal conformation; in addition, their binding free energy reached −167.936 ± 13.109 kJ/mol.