Discovery of New Selective Butyrylcholinesterase (BChE) Inhibitors with Anti-Aβ Aggregation Activity: Structure-Based Virtual Screening, Hit Optimization and Biological Evaluation

Sequential Contrastive and Deep Learning Models to Identify Selective Butyrylcholinesterase Inhibitors

Butyrylcholinesterase (BChE) is a target of interest in late-stage Alzheimer's Disease (AD) where selective BChE inhibitors (BIs) may offer symptomatic treatment without the harsh side effects of acetylcholinesterase (AChE) inhibitors. In this study, we explore multiple machine learning strategies to identify BIs in silico, optimizing for precision over all other metrics. We compare state-of-the-art supervised contrastive learning (CL) with deep learning (DL) and Random Forest (RF) machine learning, across single and sequential modeling configurations, to identify the best models for BChE selectivity. We used these models to virtually screen a vendor library of 5 million compounds for BIs and tested 20 of these compounds in vitro. Seven of the 20 compounds displayed selectivity for BChE over AChE, reflecting a hit rate of 35% for our model predictions, suggesting a highly efficient strategy for modeling selective inhibition.

Sulfonamide Derivatives: Recent Compounds with Potent Anti-alzheimer's Disease Activity

Facile synthetic procedures and broad spectrum of biological activities are special attributes of sulfonamides. Sulfonamide derivatives have demonstrated potential as a class of compounds for the treatment of Alzheimer's disease (AD). Recent sulfonamide derivatives have been reported as prospective anti-AD agents, with a focus on analogues that significantly inhibit the function of acetylcholinesterase (AChE) and butyrylcholinesterase (BChE) enzymes and exhibit remarkable antioxidant and anti-inflammatory properties, all of which are critical for the treatment of AD. Sulfonamide- mediated activation of nuclear factor erythroid 2-related factor 2 (NRF2), a key regulator of the endogenous antioxidant response, has also been suggested as a potential therapeutic approach in AD. Additionally, it has been discovered that a number of sulfonamide derivatives show selectivity for the β- and γ-secretase enzymes and a significant reduction of amyloid B (Aβ) aggregation, which have been implicated in AD. The comparative molecular docking of benzenesulfonamide and donepezil, an AD reference drug showed comparable anti-AD activities. These suggest that sulfonamide derivatives may represent a new class of drugs for the treatment of AD. Thus, the current review will focus on recent studies on the chemical synthesis and evaluation of the anti-AD properties, molecular docking, pharmacological profile, and structure-activity relationship (SAR) of sulfonamide derivatives, as well as their potential anti-AD mechanisms of action. This paper offers a thorough assessment of the state of the art in this field of study and emphasizes the potential of sulfonamide derivatives synthesized during the 2012-2023 period as a new class of compounds for the treatment of AD.

Multi-Target-Directed Cinnamic Acid Hybrids Targeting Alzheimer's Disease

Progressive cognitive decline in Alzheimer's disease (AD) is a growing challenge. Present therapies are based on acetylcholinesterase inhibition providing only temporary relief. Promising alternatives include butyrylcholinesterase (BuChE) inhibitors, multi-target ligands (MTDLs) that address the multi-factorial nature of AD, and compounds that target oxidative stress and inflammation. Cinnamate derivatives, known for their neuroprotective properties, show potential when combined with established AD agents, demonstrating improved efficacy. They are being positioned as potential AD therapeutic leads due to their ability to inhibit Aβ accumulation and provide neuroprotection. This article highlights the remarkable potential of cinnamic acid as a basic structure that is easily adaptable and combinable to different active groups in the struggle against Alzheimer's disease. Compounds with a methoxy substitution at the para-position of cinnamic acid display increased efficacy, whereas electron-withdrawing groups are generally more effective. The effect of the molecular volume is worthy of further investigation.

Enzyme ChE, cholinergic therapy and molecular docking: Significant considerations and future perspectives

Enzyme Che plays an essential role in cholinergic and non-cholinergic functions. It is present in the fertilized/unfertilized eggs and sperm of different species. Inclusion criteria for data collection from electronic databases NCBI and Google Scholar are enzyme AChE/BChE, cholinergic therapy, genomic organization and gene transcription, enzyme structure, biogenesis, transport, processing and localization, molecular signaling and biological function, polymorphism and influencing factors. Enzyme Che acts as a signaling receptor during hematopoiesis, protein adhesion, amyloid fiber formation, neurite outgrowth, bone development, and maturation, explaining the activity out of synaptic neurotransmission. Polymorphism in the Che genes correlates to various diseases and diverse drug responses. In particular, change accompanies cancer, neurodegenerative, and cardiovascular disease. Literature knowledge indicates the importance of Che inhibitors that influence biochemical and molecular pathways in disease treatment, genomic organization, gene transcription, structure, biogenesis, transport, processing, and localization of Che enzyme. Enzyme Che polymorphism changes indicate the possibility of efficient and new inhibitor drug target mechanisms in diverse research areas.

Development of Potential Multi-Target Inhibitors for Human Cholinesterases and Beta-Secretase 1: A Computational Approach

Alzheimer's disease causes chronic neurodegeneration and is the leading cause of dementia in the world. The causes of this disease are not fully understood but seem to involve two essential cerebral pathways: cholinergic and amyloid. The simultaneous inhibition of AChE, BuChE, and BACE-1, essential enzymes involved in those pathways, is a promising therapeutic approach to treat the symptoms and, hopefully, also halt the disease progression. This study sought to identify triple enzymatic inhibitors based on stereo-electronic requirements deduced from molecular modeling of AChE, BuChE, and BACE-1 active sites. A pharmacophore model was built, displaying four hydrophobic centers, three hydrogen bond acceptors, and one positively charged nitrogen, and used to prioritize molecules found in virtual libraries. Compounds showing adequate overlapping rates with the pharmacophore were subjected to molecular docking against the three enzymes and those with an adequate docking score (n = 12) were evaluated for physicochemical and toxicological parameters and commercial availability. The structure exhibiting the greatest inhibitory potential against all three enzymes was subjected to molecular dynamics simulations (100 ns) to assess the stability of the inhibitor-enzyme systems. The results of this in silico approach indicate ZINC1733 can be a potential multi-target inhibitor of AChE, BuChE, and BACE-1, and future enzymatic assays are planned to validate those results.

Dual functional antioxidant and butyrylcholinesterase inhibitors for the treatment of Alzheimer's disease: Design, synthesis and evaluation of novel melatonin-alkylbenzylamine hybrids

Here, we have designed and synthesized a series of melatonin-alkylbenzylamine hybrids as multitarget agents for the treatment of Alzheimer's disease (AD). Most of them exhibited a potent multifunctional profile involving cholinesterase inhibition and antioxidant effects. Among these compounds, compound 5 was most the potent antioxidant (ORAC = 5.13) and also an excellent selective inhibitor of BuChE (huBuChE IC₅₀ = 1.20 μM, huAChE IC₅₀ = 177.49 μM, SI = 147.91). Moreover, kinetic study indicated compound 5 was a mixed-type inhibitor for huBuChE. Furthermore, it could induce expression of the Nrf2 as well as its downstream markers at the protein level in cells. More importantly, compound 5 display no acute toxicity in mice at doses up to 2500 mg/kg. And we found compound 5 could improve memory function of scopolamine-induced amnesia mice. These results highlighted compound 5 as a possible hit molecule for further investigation of new anti-AD drugs.

Therapeutic potential of quinazoline derivatives for Alzheimer's disease: A comprehensive review

Quinazolines are considered as a promising class of bioactive heterocyclic compounds with broad properties. Particularly, the quinazoline scaffold has an impressive role in the design and synthesis of new CNS-active drugs. The drug-like properties and pharmacological characteristics of quinazoline could lead to different drugs with various targets. Among CNS disorders, Alzheimer's disease (AD) is a progressive neurodegenerative disorder with memory loss, cognitive decline and language dysfunction. AD is a complex and multifactorial disease therefore, the need for finding multi-target drugs against this devastative disease is urgent. A literature survey revealed that quinazoline derivatives have diverse therapeutic potential for AD as modulators/inhibitors of β-amyloid, tau protein, cholinesterases, monoamine oxidases, and phosphodiesterases as well as other protective effects. Thus, we describe here the most relevant and recent studies about anti-AD agents with quinazoline structure which can further aid the development and discovery of new anti-AD agents.

Discovery, biological evaluation and molecular dynamic simulations of butyrylcholinesterase inhibitors through structure-based pharmacophore virtual screening

Aim: Butyrylcholinesterase (BChE) is a crucial therapeutic target because it is associated with multiple pathological elements of Alzheimer's disease (AD). An integrated computational strategy was employed to exploit effective BChE inhibitors. Methods & results: Ten compounds derived from the Enamine database by structure-based pharmacophore virtual screening were further evaluated for biological activity; out of the ten, only five had an IC₅₀ of less than 100 μM. Among these five compounds, a new molecule, 970180, presented the most potency against BChE, with an IC₅₀ of 4.24 ± 0.16 μM, and acted as a mixed-type inhibitor. Molecular dynamic simulations and absorption, distribution, metabolism and excretion prediction further confirmed its high potential as a good candidate of BChE inhibitor. Furthermore, cytotoxicity of molecule 970180 was not observed at concentrations up to 50 μM, and the molecule also showed a prominent neuroprotective effect compared with tacrine at 25 and 50 μM. Conclusion: This study provides an effective structure-based pharmacophore virtual screening method to discover BChE inhibitors and provide new choices for the development of BChE inhibitors, which may be beneficial for AD patients.

Novel BuChE-IDO1 inhibitors from sertaconazole: Virtual screening, chemical optimization and molecular modeling studies

In our effort towards the identification of novel BuChE-IDO1 dual-targeted inhibitor for the treatment of Alzheimer's disease (AD), sertaconazole was identified through a combination of structure-based virtual screening followed by MM-GBSA rescoring. Preliminary chemical optimization was performed to develop more potent and selective sertaconazole analogues. In consideration of the selectivity and the inhibitory activity against target proteins, compounds 5c and 5d were selected for the next study. Further modification of compound 5c led to the generation of compound 10g with notably improved selectivity towards BuChE versus AChE. The present study provided us with a good starting point to further design potent and selective BuChE-IDO1 inhibitors, which may benefit the treatment of late stage AD.

Structure and therapeutic uses of butyrylcholinesterase: Application in detoxification, Alzheimer's disease, and fat metabolism

Structural information of butyrylcholinesterase (BChE) and its variants associated with several diseases are discussed here. Pure human BChE has been proved safe and effective in treating organophosphorus (OPs) poisoning and has completed Phase 1 and 2 pharmacokinetic (PK) and safety studies. The introduction of specific mutations into native BChE to endow it a self-reactivating property has gained much progress in producing effective OPs hydrolases. The hydrolysis ability of native BChE on cocaine has been confirmed but was blocked to clinical application due to poor PK properties. Several BChE mutants with elevated cocaine hydrolysis activity were published, some of which have shown safety and efficiency in treating cocaine addiction of human. The increased level of BChE in progressed Alzheimer's disease patients made it a promising target to elevate acetylcholine level and attenuate cognitive status. A variety of selective BChE inhibitors with high inhibitory activity published in recent years are reviewed here. BChE could influence the weight and insulin secretion and resistance of BChE knockout (KO) mice through hydrolyzing ghrelin. The BChE-ghrelin pathway could also regulate aggressive behaviors of BChE-KO mice.

Discovery of a Selective 6-Hydroxy-1, 4-Diazepan-2-one Containing Butyrylcholinesterase Inhibitor by Virtual Screening and MM-GBSA Rescoring

Alzheimer disease (AD) is the most common form of dementia characterized by the loss of cognitive abilities through the death of central neuronal cells. In this study, structure-based virtual screens of 2 central nervous system-targeted libraries followed by molecular mechanics/generalized born surface area rescoring were performed to discover novel, selective butyrylcholinesterase (BChE) inhibitors, which are one of the most effective therapeutic strategies for the treatments in late-stage AD. Satisfyingly, compound 5 was identified as a highly selective low micromolar inhibitor of BChE (BChE IC₅₀ = 1.4 μM). The binding mode prediction and kinetic analysis were performed to obtain detailed information about compound 5. Besides, a preliminary structure–activity relationship investigation of compound 5 was carried out for further development of the series. The present results provided a valuable chemical template with a novel scaffold for the development of selective BChE inhibitors.

Bromophenols from Symphyocladia latiuscula Target Human Monoamine Oxidase and Dopaminergic Receptors for the Management of Neurodegenerative Diseases

Progressive degeneration of dopaminergic neurons in the substantia nigra is the characteristic feature of Parkinson's disease (PD) and the severity accelerates with aging. Therefore, improving dopamine level or dopamine receptor signaling is a standard approach for PD treatment. Herein, our results demonstrate that bromophenols 2,3,6-tribromo-4,5-dihydroxybenzyl alcohol (1), 2,3,6-tribromo-4,5-dihydroxybenzyl methyl ether (2), and bis-(2,3,6-tribromo-4,5-dihydroxybenzyl) ether (3) from red alga Symphyocladia latiuscula are moderate-selective human monoamine oxidase-A inhibitors and good dopamine D₃/D₄ receptor agonists. Bromophenol 3 showed a promising D₄R agonist effect with a low micromole 50% effective concentration (EC₅₀) value. All of the test ligands were docked against a three-dimensional (3D) model of hD₃R and hD₄R, and the result demonstrated strong binding through interaction with prime interacting residues-Asp110, Cys114, and His349 on hD₃R and Asp115 and Cys119 on hD₄R. Overall, the results demonstrated natural bromophenols, especially 1 and 3, from Symphyocladia latiuscula as multitarget ligands for neuroprotection, especially in PD and schizophrenia.

Propargylamine-derived multi-target directed ligands for Alzheimer's disease therapy

Current options for the treatment of Alzheimeŕs disease have been restricted to prescription of acetylcholinesterase inhibitors or N-methyl-d-aspartate receptor antagonist, memantine. Propargylamine-derived multi-target directed ligands, such as ladostigil, M30, ASS234 and contilisant, involve different pathways. Apart from acting as inhibitors of both cholinesterases and monoamine oxidases, they show improvement of cognitive impairment, antioxidant activities, enhancement of iron-chelating activities, protect against tau hyperphosphorylation, block metal-associated oxidative stress, regulate APP and Aβ expression processing by the non-amyloidogenic α-secretase pathway, suppress mitochondrial permeability transition pore opening, and coordinate protein kinase C signaling and Bcl-2 family proteins. Other hybrid propargylamine derivatives are also reported.

Discovery of Selective Butyrylcholinesterase (BChE) Inhibitors through a Combination of Computational Studies and Biological Evaluations

As there are increased levels and activity of butyrylcholiesterase (BChE) in the late stage of Alzheimer’s disease (AD), development of selective BChE inhibitors is of vital importance. In this study, a workflow combining computational technologies and biological assays were implemented to identify selective BChE inhibitors with new chemical scaffolds. In particular, a pharmacophore model served as a 3D search query to screen three compound collections containing 3.0 million compounds. Molecular docking and cluster analysis were performed to increase the efficiency and accuracy of virtual screening. Finally, 15 compounds were retained for biological investigation. Results revealed that compounds 8 and 18 could potently and highly selectively inhibit BChE activities (IC₅₀ values < 10 μM on human BChE, selectivity index BChE > 30). These active compounds with novel scaffolds provided us with a good starting point to further design potent and selective BChE inhibitors, which may be beneficial for the treatment of AD.