Synthesis and biological evaluation of 3-arylbenzofuranone derivatives as potential anti-Alzheimer's disease agents

Validation of Acetylcholinesterase Inhibition Machine Learning Models for Multiple Species

Acetylcholinesterase (AChE) is an important enzyme and target for human therapeutics, environmental safety, and global food supply. Inhibitors of this enzyme are also used for pest elimination and can be misused for suicide or chemical warfare. Adverse effects of AChE pesticides on nontarget organisms, such as fish, amphibians, and humans, have also occurred as a result of biomagnifications of these toxic compounds. We have exhaustively curated the public data for AChE inhibition data and developed machine learning classification models for seven different species. Each set of models were built using up to nine different algorithms for each species and Morgan fingerprints (ECFP6) with an activity cutoff of 1 μM. The human (4075 compounds) and eel (5459 compounds) consensus models predicted AChE inhibition activity using external test sets from literature data with 81% and 82% accuracy, respectively, while the reciprocal cross (76% and 82% percent accuracy) was not species-specific. In addition, we also created machine learning regression models for human and eel AChE inhibition to return a predicted IC₅₀ value for a queried molecule. We did observe an improved species specificity in the regression models, where a human support vector regression model of human AChE inhibition (3652 compounds) predicted the IC₅₀s of the human test set to a better extent than the eel regression model (4930 compounds) on the same test set, based on mean absolute percentage error (MAPE = 9.73% vs 13.4%). The predictive power of these models certainly benefits from increasing the chemical diversity of the training set, as evidenced by expanding our human classification model by incorporating data from the Tox21 library of compounds. Of the 10 compounds we tested that were predicted active by this expanded model, two showed >80% inhibition at 100 μM. This machine learning approach therefore offers the ability to rapidly score massive libraries of molecules against the models for AChE inhibition that can then be selected for future in vitro testing to identify potential toxins. It also enabled us to create a public website, MegaAChE, for single-molecule predictions of AChE inhibition using these models at megaache.collaborationspharma.com.

Photobiomodulation for Hypertension and Alzheimer's Disease

Although the cause(s) of Alzheimer's disease in the majority of cases remains elusive, it has long been associated with hypertension. In animal models of the disease, hypertension has been shown to exacerbate Alzheimer-like pathology and behavior, while in humans, hypertension during mid-life increases the risk of developing the disease later in life. Unfortunately, once individuals are diagnosed with the disease, there are few therapeutic options available. There is neither an effective symptomatic treatment, one that treats the debilitating cognitive and memory deficits, nor, more importantly, a neuroprotective treatment, one that stops the relentless progression of the pathology. Further, there is no specific preventative treatment that offsets the onset of the disease. A key factor or clue in this quest for an effective preventative and therapeutic treatment may lie in the contribution of hypertension to the disease. In this review, we explore the idea that photobiomodulation, the application of specific wavelengths of light onto body tissues, can reduce the neuropathology and behavioral deficits in Alzheimer's disease by controlling hypertension. We suggest that treatment with photobiomodulation can be an effective preventative and therapeutic option for this neurodegenerative disease.

Recent Updates in Development of Small Molecules as Potential Clinical Candidates for Alzheimer's Disease: A Review

Alzheimer's disease (AD) is one of the prominent causes for disability and lowered quality of life worldwide in elderly population. It has fostered immense burden to AD patients, families and society. Burgeoning progress in the field of pathogenesis over last two decades has persuaded the investigation of novel pharmacological therapeutics that focuses towards the pathophysiological events of AD. Miscellaneous clinical trials, development and testing of interventions aimed at various targets, such as anti-tau and anti-amyloid interventions, neurotransmitter modification, neuroprotection and anti-neuroinflammation interventions, cognitive enhancement, and interventions to palliate behavioral symptoms have been carried out. Despite massive efforts to find disease modifying therapies there lingers a vital need for continuing the advancement in progress of the AD research. This review features the new developments of small molecule compounds that will be beneficial in evolution of new AD therapies. In particular, this review briefly describes summary of mechanistic causes chiefly associated with AD and focuses on medicinal approach via small molecule inhibitors that can manage cognitive impairment and dysfunction and may combat Alzheimer's development.

Polyphenolic compounds: Synthesis, assessment of antimicrobial effect and enzymes inhibition against important medicinal enzymes with computational details

Phenolic compounds mainly benefit human health and have many biological activities. Their activities are related to their structure, which allows them to interact with enzymes. The inhibition potencies of synthesized polyphenolic compounds (3a and 3b) were investigated on cholinesterases, α‑Gly, and tyrosinase activities. The structures of 3a and 3b were determined based on spectral data (NMR, UV-vis, XRD pattern, SEM, and EDX). The compounds have effective inhibitory potential with IC₅₀ value between 2.25 ± 0.35-5.66 ± 0.75 µM and Ki values 2.95 ± 0.37-14.86 ± 4.99 µM for AChE, BChE, and tyrosinase. It was determined that the synthesized compounds have biological activities by the MIC and cytotoxicity tests, and they have IC₅₀ values of 16.15 µg/mL and 12.16 µg/mL for the PC-3 cell line, respectively. According to the calculated molecular docking results, these compounds showed the highest binding energy against AChE and tyrosinase enzymes (-11.3 and -10.4 kcal/mol, respectively). The compounds have synthetic accessibility scores of 2.75 and 4.55 based on the drug-likeness properties.

New therapeutics beyond amyloid-β and tau for the treatment of Alzheimer's disease

As the population ages, Alzheimer's disease (AD), the most common neurodegenerative disease in elderly people, will impose social and economic burdens to the world. Currently approved drugs for the treatment of AD including cholinesterase inhibitors (donepezil, rivastigmine, and galantamine) and an N-methyl-D-aspartic acid receptor antagonist (memantine) are symptomatic but poorly affect the progression of the disease. In recent decades, the concept of amyloid-β (Aβ) cascade and tau hyperphosphorylation leading to AD has dominated AD drug development. However, pharmacotherapies targeting Aβ and tau have limited success. It is generally believed that AD is caused by multiple pathological processes resulting from Aβ abnormality, tau phosphorylation, neuroinflammation, neurotransmitter dysregulation, and oxidative stress. In this review we updated the recent development of new therapeutics that regulate neurotransmitters, inflammation, lipid metabolism, autophagy, microbiota, circadian rhythm, and disease-modified genes for AD in preclinical research and clinical trials. It is to emphasize the importance of early diagnosis and multiple-target intervention, which may provide a promising outcome for AD treatment.

Vitamin B3-Based Biologically Active Compounds as Inhibitors of Human Cholinesterases

We evaluated the potential of nine vitamin B3 scaffold-based derivatives as acetylcholinesterase (AChE) and butyrylcholinesterase (BChE) inhibitors, as a starting point for the development of novel drugs for treating disorders with cholinergic neurotransmission-linked pathology. As the results indicate, all compounds reversibly inhibited both enzymes in the micromolar range pointing to the preference of AChE over BChE for binding the tested derivatives. Molecular docking studies revealed the importance of interactions with AChE active site residues Tyr337 and Tyr124, which dictated most of the observed differences. The most potent inhibitor of both enzymes with K_i of 4 μM for AChE and 8 μM for BChE was the nicotinamide derivative 1-(4′-phenylphenacyl)-3-carbamoylpyridinium bromide. Such a result places it within the range of several currently studied novel cholinesterase inhibitors. Cytotoxicity profiling did not classify this compound as highly toxic, but the induced effects on cells should not be neglected in any future detailed studies and when considering this scaffold for drug development.