Synthesis, in vitro assays, molecular docking, theoretical ADMET prediction, and evaluation of 4-methoxy-phenylthiazole-2-amine derivatives as acetylcholinesterase inhibitors

Recent advances in the therapeutic insights of thiazole scaffolds as acetylcholinesterase inhibitors

Suppression of the acetylcholinesterase (AChE) enzyme is a prevalent strategy for curing diverse mental disorders, including Alzheimer's disease (AD) and the chronic autoimmune disease Myasthenia gravis. Acetylcholinesterase inhibitors promote cholinergic transmission via blocking AChE, which is implicated in the degradation and deficiency of acetylcholine. Various studies proved that the lack of cholinergic neurons in the central nervous system is the substantial reason for the behavioral abnormalities and cognitive retogradation that distinguish mental diseases such as dementia and AD. Moreover, thiazole scaffolds have emerged as prominent pharmacophores in drug discovery owing to their numerous outstanding therapeutic efficacy, comprising anti-acetylcholinesterase efficacy. This review presents various thiazole-based AChE inhibitors in the recent decade. In addition, the various interactions of thiazole derivatives within the active pocket of AChE have been highlighted. Also, structure-activity relationship (SAR) has been discussed.

An insight into the mechanisms of action of selected bioactive compounds against epigenetic targets of prostate cancer: implications on histones modifications

Prostate cancer is a leading cause of morbidity and mortality among men globally. In this study, we employed an in silico approach to predict the possible mechanisms of action of selected novel compounds reported against prostate cancer epigenetic targets and their derivatives, exhausting through ADMET profiling, drug-likeness, and molecular docking analyses. The selected compounds: sulforaphane, silibinin, 3, 3'-diindolylmethane (DIM), and genistein largely conformed to ADMET and drug-likeness rules including Lipinski's. Docking studies revealed strong binding energy of sulforaphane with HDAC6 (- 4.2 kcal/ mol), DIM versus HDAC2 (- 5.2 kcal/mol), genistein versus HDAC6 (- 4.1 kcal/mol), and silibinin against HDAC1 (- 7.0 kcal/mol) coupled with improved binding affinities and biochemical stabilities after derivatization. Findings from this study may provide insight into the potential epigenetic reprogramming mechanisms of these compounds against prostate cancer and could pave the way toward more success in prostate cancer phytotherapy.

Synthesis, anticholinesterase activity, molecular docking, and molecular dynamic simulation studies of 1,3,4-oxadiazole derivatives

Two new series of 1,3,4-oxadiazoles bearing pyridine and thiazole heterocycles (4a-h and 5a-h) were synthesized (2,5-disubstituted-1,3,4-oxadiazoles). The structures of these newly synthesized compounds were confirmed by ¹ H nuclear magnetic resonance (NMR), ¹³ C NMR, high-resolution mass spectrometric and Fourier transform infrared spectroscopic methods. All these compounds were evaluated for their enzyme inhibitory activities against two cholinesterase enzymes, acetylcholinesterase (AChE) and butyrylcholinesterase (BChE). From the studies, we identified compounds 4a, 4h, 5a, 5d, and 5e as selective AChE inhibitors, with IC₅₀ values ranging from 0.023 to 0.037 μM. Furthermore, docking studies of these compounds were performed at the active sites of their target enzymes. The molecular docking study showed that 5e possessed an ideal docking pose with interactions inside AChE.

Molecular design, molecular docking and ADMET study of cyclic sulfonamide derivatives as SARS-CoV-2 inhibitors

Severe acute respiratory syndrome coronavirus type 2 (SARS-CoV-2) continues to spread globally with more than 172 million confirmed cases and 3.57 million deaths. Cyclic sulfonamide derivative is identified as a successful compound and showed anti-SARS-CoV-2 activity. In this study, the structure and activity relationships of 35 cyclic sulfonamide compound inhibitors are investigated by using three-dimensional quantitative structure-activity relationship (3D-QSAR) and holographic quantitative structure-activity relationship (HQSAR). Two models with good statistical parameters and reliable predictive ability are obtained from the same training set, including Topomer CoMFA (q2= 0.623,r2= 0.938,rpred2= 0.893) model and HQSAR (q2= 0.704,r2= 0.958,rpred2=0.779) model. The established models not only have good stability, but also show good external prediction ability for the test set. The contour and color code maps of the models provide a lot of useful information for determining the structural requirements which might affect the activity; this information paves the way for the design of four novel cyclic sulfonamide compounds, and predictes their pIC₅₀ values. We explore the interaction between the newly designed molecule and SARS-CoV-2 3CLpro by molecular docking. The docking results show that GLU166, GLN192, ALA194, and VAL186 may be the potential active residues of the SARS-CoV-2 inhibitor evaluated in this study. Finally, the oral bioavailability and toxicity of the newly designed cyclic sulfonamide compounds are evaluated and the results show that the four newly designed cyclic sulfonamide compounds have major ADMET properties and can be used as reliable inhibitors against COVID-19. These results may provide useful insights for the design of effective SARS-CoV-2 inhibitors.

Design, Synthesis, and Structure-Activity Relationships of Thiazole Analogs as Anticholinesterase Agents for Alzheimer's Disease

Dementia is a neurological condition commonly correlated with Alzheimer's disease (AD), and it is seen with many other central nervous system (CNS) disorders. The restricted number of medications is not appropriate to offer enough relief to enhance the quality of life of patients suffering from this symptom; thus, all therapeutic choices should be carefully assessed. In this study, new thiazolylhydrazone derivatives (2a-2l) were designed and synthesized based on the cholinergic hypothesis. Their chemical structures were confirmed by 1H NMR, 13C NMR, and HRMS spectrometric techniques. The ADME (absorption, distribution, metabolism, elimination) parameters of the synthesized compounds were predicted by using QikProp 4.8 software. It was concluded that all compounds presented satisfactory drug-like characteristics. Furthermore, their inhibitory activities against acetylcholinesterase (AChE) and butyrylcholinesterase (BChE) in vitro were also tested by modified the Ellman spectrophotometric method. According to the results, all compounds showed a weak inhibitory effect on BChE. On the other hand, most of the compounds (2a, 2b, 2d, 2e, 2g, 2i, and 2j) had a certain AChE inhibitory activity, and the IC50 values of them were calculated as 0.063 ± 0.003, 0.056 ± 0.002, 0.147 ± 0.006, 0.040 ± 0.001, 0.031 ± 0.001, 0.028 ± 0.001, and 0.138 ± 0.005 µM, respectively. Among these derivatives, compound 2i was found to be the most active agent in the series with an IC50 value of 0.028 ± 0.001 µM, which indicated an inhibition profile at a similar rate as the reference drug, donepezil. The potential binding modes of compounds 2a, 2b, 2e, 2g, and 2i with AChE were investigated and compared with each other by the molecular docking studies. The results showed that these compounds were strongly bound up with the AChE enzyme active site with the optimal conformations.