Synthesis and In Vitro Screening of Novel Heterocyclic β-d-Gluco- and β-d-Galactoconjugates as Butyrylcholinesterase Inhibitors

Butyrylcholinesterase inhibitors as potential anti-Alzheimer's agents: an updated patent review (2018-present)

INTRODUCTION

Alzheimer's disease (AD) constitutes one of the most complex and devastating diseases, with an extraordinarily high increase expected for the next few years. Despite the numerous efforts accomplished so far there is still no cure but just palliative treatments.

AREAS COVERED

The main topic covered herein has been the development of butyrylcholinesterase (BuChE) inhibitors with the aim of increasing the levels of the neurotransmitter acetylcholine (ACh). Two main groups of compounds have been considered: multitarget and non-multitarget ligands, depending if the structural design is focused or not on other key targets and pathogenic factors of the disease. Seventeen patents regarding multitarget-directed ligands (MTDLs), twelve for not multitarget derivatives, and three for miscellaneous uses have been covered in the period 2018‒2021.

EXPERT OPINION

BuChE is an attractive target in the treatment of AD for many reasons. It is the most prevalent cholinesterase within more advanced stages of the disease, so drugs inhibiting it would be suitable for the treatment of mid- to severe Alzheimer's patients. Moreover, BuChE has been proved to be connected with some other key hallmarks of the disease, like amyloidogenesis; hybridization of a BuChE-targeting pharmacophore with other scaffolds designed for other therapeutic targets is quite a promising design for potential anti-Alzheimer's drugs.

Dimethoxyindoles based thiosemicarbazones as multi-target agents; synthesis, crystal interactions, biological activity and molecular modeling

Alzheimer's disease (AD) is known as one of the most devastating neurodegenerative disease diagnosed for the old-aged people and cholinesterase inhibitors (ChEI) can be used as an effective palliative treatment for AD. A range of novel monomeric and dimeric indole based thiosemicarbazone derivatives 17-28 was synthesized in order to target cholinesterases (ChE). Biological importance of the targeted compounds 17-28 was investigated by employing the acetylcholinesterase (AChE) and butyrylcholinesterase (BChE) enzymes along with three different antioxidant property determination assays, namely DPPH free radical scavenging, ABTS cationic radical decolarization, and CUPRAC cupric reducing antioxidant capacity. The compounds 18 and 19 displayed the best inhibitor activity against BChE with IC₅₀ values of 7.42 and 1.95 μM, respectively. The antioxidant potentials were found to be moderate for DPPH and ABTS assays and the compounds 28 and 18 were the most potent candidates for both antioxidant assays. Cupric reducing capacity was the most promising assay and the compounds 25, 26 and 28 provided better inhibition values than all the standards. Further binding mode and affinity studies performed by molecular docking and molecular dynamics simulations. Accordingly, the compound 19 is the most plausible candidate that can compete with galantamine (GNT), a common pharmaceutics targeting both cholinesterase enzymes.

An overview on the synthesis of carbohydrate-based molecules with biological activity related to neurodegenerative diseases

In the context of the search for multitarget drugs with improved efficacy against neurodegenerative disorders, carbohydrate derivatives have emerged as promising candidates for Alzheimer's therapy. Herein we describe the synthesis and biological evaluation of several classes of sugar-based compounds, where most of them contain heterocyclic aromatic moieties that bear known biological properties and high affinity for the cholinesterase active site. This general idea led to the synthesis of compounds with high inhibitory potency against acetylcholinesterase (AChE) and butyrylcholinesterase (BuChE), enzymatic selectivity and combined properties such as antioxidant and neuroprotection, in addition to the absence of toxicity.

Evidence-based complementary and alternative medicine bioinformatics approach through network pharmacology and molecular docking to determine the molecular mechanisms of Erjing pill in Alzheimer's disease

Erjing pill, a Traditional Chinese Medicine (TCM) formulation composed of Polygonatum sibiricum and Lycium chinense, has an important role in the treatment of Alzheimer's disease (AD). However, the underlying mechanisms of the action of Erjing pill in AD have remained elusive. In the present study, the key ingredients of Erjing pill were investigated and the active components and their mechanisms of action on AD were analyzed based on networks pharmacology. By using the TCM and TCM Systems Pharmacology and databases, the components of Erjing pill were screened and the data were captured using Discovery Studio. The SwissTarget webserver database was used to predict the potential protein targets of Erjing pill components for pathologies related to AD. The data were further analyzed with the disease targets of AD based on analysis of the Online Mendelian Inheritance in Man, DiGSeE and Therapeutic Target Database. Subsequent analysis of mechanistic pathways of the screened components and protein targets allowed us to construct a network by using Gene Ontology and Kyoto Encyclopedia of Genes and Genomes, which revealed potential molecular mechanisms of Erjing pill against AD. Finally, the protective effect of three active components on neurons was verified using an in vitro injury model of PC12 cells induced by Aβ25-35. The results indicated that 65 bioactive components of Erjing pill, including lauric acid and zederone, and 6 targets, including acetylcholinesterase, butylcholinesterase and amyloid protein precursor, were closely associated with the prevention and treatment of AD. The molecular components of Erjing pill were indicated to be involved in various biological signaling processes, mainly in synaptic signal transmission, transsynaptic signal transmission and chemical synaptic transmission. Furthermore, related pathways targeted by Erjing pill in AD included the regulation of neuroactive ligand-receptor interactions, the PI3K-Akt signaling pathway, serotoninergic synapses, calcium signaling pathways and dopaminergic synapses. A cell viability assay indicated that the compounds (polygonatine A, polygonatine C and 4',5-dihydroxyflavone) assessed were able to significantly improve the survival rate and increase the Ca2+ level in a PC12 cell model of AD induced by amyloid-β25-35. The present study revealed that the mechanisms of action of Erjing pill to prevent and treat AD included a multicompound, multitarget and multipathway regulatory network.