Search

Alzheimer's disease, the most common form of dementia, is characterized by the deposition of amyloid plaques and neurofibrillary tangles in the brain, leading to the loss of neurons and a decline in a person's memory and cognitive function. As a multifactorial disease, Alzheimer's involves multiple pathogenic mechanisms, making its treatment particularly challenging. Current drugs approved for the treatment of Alzheimer's disease only alleviate symptoms but cannot stop the progression. Moreover, these drugs typically target a single pathogenic mechanism, leaving other contributing factors unaddressed. Recent advancements in drug design have led to the development of multi-target-directed ligands (MTDLs), which have gained popularity for their ability to simultaneously target multiple pathogenic mechanisms. This paper focuses on analyzing the activity, mechanism of action, and binding properties of the anti-Alzheimer's MTDLs developed between 2020 and 2024. [ABSTRACT FROM AUTHOR]

Based on the multi-target-directed ligands (MTDLs) approach, two series of tryptanthrin derivatives with benzenesulfonamide substituents were evaluated as multifunctional agents for the treatment of Alzheimer's disease (AD). In vitro biological assays indicated most of the derivatives had good cholinesterase inhibitory activity and neuroprotective properties. Among them, the target compound 4h was considered as a mixed reversible dual inhibitor of acetylcholinesterase (AChE, IC50 = 0.13 ± 0.04 μM) and butyrylcholinesterase (BuChE, IC50 = 6.11 ± 0.15 μM). And it could also potentially prevent the generation of amyloid plaques by inhibiting self-induced Aβ aggregation (63.16 ± 2.33%). Molecular docking studies were used to explore the interactions of AChE, BuChE, and Aβ. Furthermore, possessing significant anti-neuroinflammatory potency (NO, IL-1β, TNF-α; IC50 = 0.62 ± 0.07 μM, 1.78 ± 0.21 μM, 1.31 ± 0.28 μM, respectively) reduced ROS production, and chelated biometals were also found in compound 4h. Further studies showed that 4h had proper blood–brain barrier (BBB) permeability and suitable in vitro metabolic stability. In in vivo study, 4h effectively ameliorated the learning and memory impairment of the scopolamine-induced AD mice model. These findings suggested that 4h may be a promising compound for further development as a multifunctional agent for the treatment of AD. [ABSTRACT FROM AUTHOR]

Prion diseases are fatal neurodegenerative disorders, for which there are no effective therapeutic and diagnostic agents. The main pathological hallmark has been identified as conformational changes of the cellular isoform prion protein (PrPC) to a misfolded isoform of the prion protein (PrPSc). Targeting PrPC and its conversion to PrPSc is still the central dogma in prion drug discovery, particularly in in silico and in vitro screening endeavors, leading to the identification of many small molecules with therapeutic potential. Nonetheless, multiple pathological targets are critically involved in the intricate pathogenesis of prion diseases. In this context, multi-target-directed ligands (MTDLs) emerge as valuable therapeutic approach for their potential to effectively counteract the complex etiopathogenesis by simultaneously modulating multiple targets. In addition, diagnosis occurs late in the disease process, and consequently a successful therapeutic intervention cannot be provided. In this respect, small molecule theranostics, which combine imaging and therapeutic properties, showed tremendous potential to cure and diagnose in vivo prion diseases. Herein, we review the major advances in prion drug discovery, from anti-prion small molecules identified by means of in silico and in vitro screening approaches to two rational strategies, namely MTDLs and theranostics, that have led to the identification of novel compounds with an expanded anti-prion profile. [ABSTRACT FROM AUTHOR]

• Three novel series were designed, synthesized, and evaluated as anti-AD agents. • 4b emerged as a lead candidate against BChE. • 4b has the best neuroprotective potency and better antioxidant compared to hit. • 4b was more effective in inhibiting the levels of IL-1β, IL-6, TNF-α, and NO. • 4b did not exhibit any cytotoxic effect on the PC12 cell line. In the current study, three series of new compounds were designed and synthesized through hit optimization, based on the hit compound with a structure (E)-N-(4-{[benzyl(methyl)amino]methyl}thiazol-2-yl)-3-(3,4-dimethoxyphenyl)prop‑2-enamide, which was found as a potential multifunctional anti-Alzheimer agent in our previous study. Then, the biological activities of synthesized compounds (4a-c, 13a-b and 15a-c) were evaluated. The results indicated that 4b , a 2-phenoxyacetamide derivative, exhibited good multifunctional activities. Namely, compound 4b displayed better BChE inhibition (BChE IC 50 = 2.10 µM) and antioxidant activity (ORAC = 1.18 Trolox equivalents) compared to the hit compound (BChE IC 50 = 14.70 µM, ORAC = 0.5 Trolox equivalents). Additionally, 4b was able to chelate all tested biometals and it also exhibited a neuroprotective effect (63 %), comparable to reference ferulic acid (77 %) while maintaining its safety upon PC12 cell line. When it comes to lowering the levels of TNF-α, NO, IL-1β, and IL-6, 4b performed better activity, relative to the other synthesized compounds. Subsequently, in silico studies such as physicochemical properties, density functional theory (DFT) computational approach and molecular docking studies were performed. [Display omitted] [ABSTRACT FROM AUTHOR]

Alzheimer's disease (AD, also known as dementia) has become a serious global health problem along with population aging, and neuroinflammation is the underlying cause of cognitive impairment in the brain. Nowadays, the development of multitarget anti-AD drugs is considered to be one effective approach. Imidazolylacetophenone oxime ethers or esters (IOEs) were multifunctional agents with neuroinflammation inhibition, metal chelation, antioxidant and neuroprotection properties against Alzheimer's disease. In this study, IOEs derivatives 1 − 8 were obtained by structural modifications of the oxime and imidazole groups, and the SARs showed that (Z)-oxime ether (derivative 2) had stronger anti-neuroinflammatory and neuroprotective ability than (E)-congener. Then, IOEs derivatives 9 − 30 were synthesized based on target-directed ligands and activity-based groups hybridization strategy. In vitro anti-AD activity screening revealed that some derivatives exhibited potentially multifunctional effects, among which derivative 28 exhibited the strongest inhibitory activity on NO production with EC 50 value of 0.49 μM, and had neuroprotective effects on 6-OHDA-induced cell damage and RSL3-induced ferroptosis. The anti-neuroinflammatory mechanism showed that 28 could inhibit the release of pro-inflammatory factors PGE 2 and TNF-α, down-regulate the expression of iNOS and COX-2 proteins, and promote the polarization of BV-2 cells from pro-inflammatory M1 phenotype to anti-inflammatory M2 phenotype. In addition, 28 can dose-dependently inhibit acetylcholinesterase (AChE) and Aβ 42 aggregation. Moreover, the selected nuclide [18F]-labeled 28 was synthesized to explore its biodistribution by micro-PET/CT, of which 28 can penetrate the blood-brain barrier (BBB). These results shed light on the potential of 28 as a new multifunctional candidate for AD treatment. [Display omitted] • Neuroprotective activity of (Z)-oxime ethers is superior to that of (E)-congeners. • 28 displayed strong NO inhibitory activity with EC 50 of 0.49 μM. • 28 increased Arg-1 and IL-10 expressions to promote the microglia polarization. • 28 could inhibit Aβ 42 aggregation and dose-dependently inhibit AChE. • [18F] 28 was successfully synthesized and could penetrate the blood-brain barrier. [ABSTRACT FROM AUTHOR]

The conventional treatment of neurodegenerative diseases (NDDs) is based on the "one molecule—one target" paradigm. To combat the multifactorial nature of NDDs, the focus is now shifted toward the development of small-molecule-based compounds that can modulate more than one protein target, known as "multi-target-directed ligands" (MTDLs), while having low affinity for proteins that are irrelevant for the therapy. The in silico approaches have demonstrated a potential to be a suitable tool for the identification of MTDLs as promising drug candidates with reduction in cost and time for research and development. In this study more than 650,000 compounds were screened by a series of in silico approaches to identify drug-like compounds with predicted activity simultaneously towards three important proteins in the NDDs symptomatic treatment: acetylcholinesterase (AChE), histone deacetylase 2 (HDAC2), and monoamine oxidase B (MAO-B). The compounds with affinities below 5.0 µM for all studied targets were additionally filtered to remove known non-specifically binding or unstable compounds. The selected four hits underwent subsequent refinement through in silico blood-brain barrier penetration estimation, safety evaluation, and molecular dynamics simulations resulting in two hit compounds that constitute a rational basis for further development of multi-target active compounds against NDDs. [ABSTRACT FROM AUTHOR]

[Display omitted] • Synthesis of novel MTDLs homodimers inspired by riluzole 2a-c was planned. • Compounds 3a-c and expanded intermediates 4a-c were serendipitously achieved and characterized. • Compound 3b exhibited a concentration-dependent neuroprotective effect. • Derivative 3b induced a multifaceted inhibitory effect on Na+ and K+ currents in SH-SY5Y neurons. • Bioactive compound 3b represented an elegant example of a MTDL. Riluzole, the first clinically approved treatment for amyotrophic lateral sclerosis (ALS), represents a successful example of a drug endowed with a multimodal mechanism of action. In recent years, different series of riluzole-based compounds have been reported, including several agents acting as Multi-Target-Directed Ligands (MTLDs) endowed with neuroprotective effects. Aiming at identical twin structures inspired by riluzole (2a-c), a synthetic procedure was planned, but the reactivity of the system took a different path, leading to the serendipitous isolation of benzo[ b ][1,4]thiazepines 3a-c and expanded intermediates N -cyano-benzo[ b ][1,4]thiazepines 4a-c , which were fully characterized. The newly obtained structures 3a-c , bearing riluzole key elements, were initially tested in an in vitro ischemia/reperfusion injury protocol, simulating the cerebral stroke. Results identified compound 3b as the most effective in reverting the injury caused by an ischemia-like condition, and its activity was comparable, or even higher than that of riluzole, exhibiting a concentration-dependent neuroprotective effect. Moreover, derivative 3b completely reverted the release of Lactate Dehydrogenase (LDH), lowering the values to those of the control slices. Based on its very promising pharmacological properties, compound 3b was then selected to assess its effects on voltage-dependent Na+ and K+ currents. The results indicated that derivative 3b induced a multifaceted inhibitory effect on voltage-gated currents in SH-SY5Y differentiated neurons, suggesting its possible applications in epilepsy and stroke management, other than ALS. Accordingly, brain penetration was also measured for 3b , as it represents an elegant example of a MTDL and opens the way to further ex-vivo and/or in-vivo characterization. [ABSTRACT FROM AUTHOR]

Backgrounds: Alzheimer’s disease (AD) is a multifactorial neurodegenerative disease. The treatment of AD through multiple pathological targets may generate therapeutic efficacy better. The multifunctional molecules that simultaneously hit several pathological targets have been of great interest in the intervention of AD. Methods: Here, we combined the chalcone scaffold with carbamate moiety and 5,6-dimethoxy-indanone moiety to generate a novel multi-target-directed ligand (MTDL) molecule (E)-3-((5,6-dimethoxy-1-oxo-1,3-dihydro-2H-inden-2-ylidene)- methyl)phenylethyl(methyl) carbamate (named AP5). In silico approaches were used to virtually predict the binding interaction of AP5 with AChE, the drug-likeness, and BBB penetrance, and later validated by evaluation of pharmacokinetics (PK) in vivo by LCMS/ MS. Moreover, studies were conducted to examine the potential of AP5 for inhibiting AChE and AChE-induced amyloid-b (Ab) aggregation, attenuating neuroinflammation, and providing neuroprotection in the APP/PS1 model of AD. Results: We found that AP5 can simultaneously bind to the peripheral and catalytic sites of AChE by molecular docking. AP5 exhibited desirable pharmacokinetic (PK) characteristics including oral bioavailability (67.2%), >10% brain penetrance, and favorable drug-likeness. AP5 inhibited AChE activity and AChE-induced Ab aggregation in vivo and in vitro. Further, AP5 lowered Ab plaque deposition and insoluble Ab levels in APP/PS1 mice. Moreover, AP5 exerted anti-inflammatory responses by switching microglia to a disease-associated microglia (DAM) phenotype and preventing A1 astrocytes formation. The phagocytic activity of microglial cells to Ab was recovered upon AP5 treatment. Importantly, chronic AP5 treatment significantly prevented neuronal and synaptic damage and memory deficits in AD mice. Conclusion: Together, our work demonstrated that AP5 inhibited the AChE activity, decreased Ab plaque deposition by interfering Ab aggregation and promoting microglial Ab phagocytosis, and suppressed inflammation, thereby rescuing neuronal and synaptic damage and relieving cognitive decline. Thus, AP5 can be a new promising candidate for the treatment of AD [ABSTRACT FROM AUTHOR]

The accumulation of tau-containing neurofibrillary tangles and beta-amyloid deposits has been identified as the hallmark of Alzheimer's disease. Alzheimer's disease (AD) is a hereditary and neurological condition that can result in non-amnestic cognitive decline in less common forms and amnestic memory loss in its classic form. While Alzheimer's disease is the most prevalent cause of memory loss in middle-aged and older adults, other neurodegenerative and cerebrovascular disorders can have an impact on the disease's clinical course. Designing multi-target-directed ligands (MTDLs) is a very promising modern approach. This methodology was designed specifically for treating disorders with complex pathological mechanisms. Among these disorders is Alzheimer's disease (AD), which is currently the most prevalent multifactorial neurodegenerative illness. Increased amounts of the amyloid βpeptide (Aβ) and hyperphosphorylated tau protein, together with the loss of neurons and synapses, are linked to Alzheimer's disease (AD). Additionally, there is evidence that the pathophysiology of this condition is influenced by oxidative stress, metal ion dysregulation, inflammation, and failure of the cell cycle regulatory system. Since Alzheimer's disease (AD) is a multi-factor illness, there are many attractive targets for the development of anti-AD medications. These molecules can be useful in treating AD since they are multi-target-directed. This review focuses on the discovery of dual and multi-acting anti-AD drug candidates, especially hybrids made by combining chemically active moieties that function against distinct targets. The first group of substances consists of cholinesterase inhibitors with extra properties or those that function as multiple binding site inhibitors. Natural products also provide numerous options for slowing the progression and symptoms of many diseases, including Alzheimer's Meanwhile, Natural chemical structures with the following characteristics: alkaloids, sterols, triterpenes, tannins, flavonoids, polyphenols, and antioxidants as well as anti-inflammatory and anti-amyloidogenic properties. We provide an overview of Alzheimer's disease pathophysiology and therapy targets in this study. We also show several isolated chemicals and medicinal plants that are used to treat and prevent the symptoms of Alzheimer's disease., (Copyright© Bentham Science Publishers; For any queries, please email at epub@benthamscience.net.)

A new series of N-benzylpiperidine 8-hydroxyquinoline derivatives were synthesized and evaluated as cholinesterase inhibitors, metal ion chelators and calcium channel blockers. It was found that the ethyl cholinesterase inhibition activity could be improved when the linker between N-benzylpiperidine and 8‑hydroxyquinoline groups were extended. Among all derivatives, compound (XIIId) showed best acetyl cholinesterase inhibition activity with an IC50 value of 0.24 ± 0.03 μM. It also showed metal ion chelating activity with a metal-compound ratio of 1 : 2 on copper or zinc ions. The calcium channel blocking property of select compounds were tested and compared by patching clamp on HEK293 cell expressing Cav1.2 calcium channel. Among tested compounds, cholinesterase inhibitor 8c showed mild calcium channel blockade activity with the inhibition ratio of calcium channel of 24.56 ± 2.44% (10 μM). This result suggested that the potential neuroprotective ability of this cholinesterase inhibitor might be partially related to the calcium channel blocking property. [ABSTRACT FROM AUTHOR]

The design of multi-target directed ligands (MTDLs) is a valid approach for obtaining effective drugs for complex pathologies. MTDLs that combine neuro-repair properties and block the first steps of neurotoxic cascades could be the so long wanted remedies to treat neurodegenerative diseases (NDs). By linking two privileged scaffolds with well-known activities in ND-targets, the flavonoid and the N,N-dibenzyl(N-methyl)amine (DBMA) fragments, new CNS-permeable flavonoid – DBMA hybrids (1–13) were obtained. They were subjected to biological evaluation in a battery of targets involved in Alzheimer’s disease (AD) and other NDs, namely human cholinesterases (hAChE/hBuChE), β-secretase (hBACE-1), monoamine oxidases (hMAO-A/B), lipoxygenase-5 (hLOX-5) and sigma receptors (σ1R/σ2R). After a funnel-type screening, 6,7-dimethoxychromone – DBMA (6) was highlighted due to its neurogenic properties and an interesting MTD-profile in hAChE, hLOX-5, hBACE-1 and σ1R. Molecular dynamic simulations showed the most relevant drug-protein interactions of hybrid 6, which could synergistically contribute to neuronal regeneration and block neurodegeneration.

Alzheimer's disease (AD) is one of the most common forms of dementia among elder people, which is a progressive neurodegenerative disease that results from a chronic loss of cognitive activities. It has been observed that AD is multifactorial, hence diverse pharmacological targets that could be followed for the treatment of AD. The Food and Drug Administration has approved two types of medications for AD treatment such as cholinesterase inhibitors (ChEIs) and N-methyl-d-aspartic acid receptor (NMDAR) antagonists. Rivastigmine, donepezil, and galantamine are the ChEIs that have been approved to treat AD. On the other hand, memantine is the only non-competitive NMDAR antagonist approved in AD treatment. As compared with placebo, it has been revealed through clinical studies that many single-target therapies are unsuccessful to treat multifactorial Alzheimer's symptoms or disease progression. Therefore, due to the complex nature of AD pathophysiology, diverse pharmacological targets can be hunted. In this article, based on the entwined link of acetylcholinesterase (AChE) and NMDAR, we represent several multifunctional compounds in the rational design of new potential AD medications. This review focus on the significance of privileged scaffolds in the generation of the multi-target lead compound for treating AD, investigating the idea and challenges of multi-target drug design. Furthermore, the most auspicious elementary units for designing as well as synthesizing hybrid drugs are demonstrated as pharmacological probes in the rational design of new potential AD therapeutics. [ABSTRACT FROM AUTHOR]

The multi-target-directed ligands (MTDLs) strategy is encouraged for the development of novel modulators targeting multiple pathways in the neurodegenerative cascade typical for Alzheimer’s disease (AD). Based on the structure of an in-house irreversible monoamine oxidase B (MAO-B) inhibitor, we aimed to introduce a carbamate moiety on the aromatic ring to impart cholinesterase (ChE) inhibition, and to furnish multifunctional ligands targeting two enzymes that are intricately involved in AD pathobiology. In this study, we synthesized three dual hMAO-B/hBChE inhibitors 13–15, with compound 15 exhibiting balanced, low micromolar inhibition of hMAO-B (IC50 of 4.3 µM) and hBChE (IC50 of 8.5 µM). The docking studies and time-dependent inhibition of hBChE confirmed the initial expectation that the introduced carbamate moiety is responsible for covalent inhibition. Therefore, dual-acting compound 15 represents an excellent starting point for further optimization of balanced MTDLs

Alzheimer's disease (AD) represents a major public health threat and, unfortunately, available therapeutics provide only temporary symptomatic relief. AD is a complex multifactorial disease and failure of single target therapeutics targeting amyloid-β (Aβ) in recent clinical trials suggests that future AD drug development should be focused on simultaneous targeting of several pathological hallmarks of the disease. Recently, we have shown that GMP-1, a 2-(methoxymethyl)pyrimido [1, 2-a] benzimidazol-4-ol, protects mitochondrial function in drosophila and mice models of AD, and improved memory and behavior indicating neuroprotective effect of GMP-1 treatment. Here, we have found that GMP-1 specifically binds to copper and zinc, metals that are dysregulated in AD brain. Addition of GMP-1 does not inhibit metal-dependent enzymatic reactions. Also, binding of Zn(II) and Cu(II) by GMP-1 is weaker than the 8-hydroxyquinoline scaffold compound clioquinol previously tested in AD clinical trials. However, GMP-1 affects Cu(II)-dependent Aβ fibrillization as well as oxidative damage and viability of SH-SY5Y cells upon addition of Cu(II) and Aβ. Our data provide new insight on GMP-1 as a Zn(II) and Cu(II) specific metal chelator of moderate affinity that can be responsible for some of its neuroprotective effects observed in AD animal models. [ABSTRACT FROM AUTHOR]

The design of multi-target directed ligands (MTDLs) is a valid approach for obtaining effective drugs for complex pathologies. MTDLs that combine neuro-repair properties and block the first steps of neurotoxic cascades could be the so long wanted remedies to treat neurodegenerative diseases (NDs). By linking two privileged scaffolds with well-known activities in ND-targets, the flavonoid and the N,N-dibenzyl(N-methyl)amine (DBMA) fragments, new CNS-permeable flavonoid – DBMA hybrids (1–13) were obtained. They were subjected to biological evaluation in a battery of targets involved in Alzheimer's disease (AD) and other NDs, namely human cholinesterases (hAChE/hBuChE), β-secretase (hBACE-1), monoamine oxidases (hMAO-A/B), lipoxygenase-5 (hLOX-5) and sigma receptors (σ1R/σ2R). After a funnel-type screening, 6,7-dimethoxychromone – DBMA (6) was highlighted due to its neurogenic properties and an interesting MTD-profile in hAChE, hLOX-5, hBACE-1 and σ1R. Molecular dynamic simulations showed the most relevant drug-protein interactions of hybrid 6, which could synergistically contribute to neuronal regeneration and block neurodegeneration. [ABSTRACT FROM AUTHOR]

The development of multitarget compounds against multifactorial diseases, such as Alzheimer's disease, is an area of very intensive research, due to the expected superior therapeutic efficacy that should arise from the simultaneous modulation of several key targets of the complex pathological network. Here we describe the synthesis and multitarget biological profiling of a new class of compounds designed by molecular hybridization of an NMDA receptor antagonist fluorobenzohomoadamantanamine with the potent acetylcholinesterase (AChE) inhibitor 6-chlorotacrine, using two different linker lengths and linkage positions, to preserve or not the memantine-like polycyclic unsubstituted primary amine. The best hybrids exhibit greater potencies than parent compounds against AChE (IC 50 0.33 nM in the best case, 44-fold increased potency over 6-chlorotacrine), butyrylcholinesterase (IC 50 21 nM in the best case, 24-fold increased potency over 6-chlorotacrine), and NMDA receptors (IC 50 0.89 μM in the best case, 2-fold increased potency over the parent benzohomoadamantanamine and memantine), which suggests an additive effect of both pharmacophoric moieties in the interaction with the primary targets. Moreover, most of these compounds have been predicted to be brain permeable. This set of biological properties makes them promising leads for further anti-Alzheimer drug development. Image 1 • A novel class of fluorobenzohomoadamantanamine‒chlorotacrine hybrids was synthesized. • The hybrids are up to 44-fold more potent than 6-chlorotacrine for hAChE inhibition. • The hybrids are up to 24-fold more potent than 6-chlorotacrine for hBChE inhibition. • The hybrids are up to 2-fold more potent than memantine for NMDA antagonism. • Most of the hybrids are brain permeable, according to the PAMPA-BBB assay. [ABSTRACT FROM AUTHOR]

The identification of a valid therapeutic treatment for Alzheimer's disease (AD) represents nowadays an urgent and still unmet medical need, since currently available anti-AD drugs only relieve symptoms and show a modest efficacy. Recent evidence indicates that multi-target-directed ligands (MTDLs) can potentially provide an effective strategy to develop innovative therapies directed towards the onset and progression of this multifactorial neurodegenerative disorder. In this work we designed, synthesized and evaluated a new series of MTDLs bearing the rivastigmine skeleton (ChE-inhibitor) linked to known metal-chelating moieties with linkers of different length. For all the novel derivatives, AChE/BuChE inhibitory activity, ROS scavenging activity and potential cytotoxicity have been assessed. For the best compound (4), copper chelating properties and neuroprotective effects were also evaluated. Our data demonstrated that hybrid derivative 4 is able to effectively inhibit AChE and BuChE and to chelate copper, showing a protective action on neurons. These results, although preliminary, indicate that compound 4 can be considered as a possible hit molecule for the development of new anti-AD MTDLs. Image 1 • A new series of MTDLs bearing the rivastigmine skeleton linked to known metal-chelating moieties has been synthesised. • The hybrid 4 showed a Cu-chelating activity evaluated with UV-vis spectrometry. • The MTDL compound 4 inhibits cholinesterase's activity and decreases ROS level, exerting an overall neuroprotective effect. [ABSTRACT FROM AUTHOR]

Abstract Tacrine was the first drug approved for the treatment of Alzheimer's disease (AD) in 1993, which was withdrawn in 2013 due to its hepatotoxicity. However, new, non-hepatotoxic tacrine derivatives have been constantly searched for. In this context, since 1997, we have prepared a number of diversely functionalized tacrines by changing the benzene ring present in tacrine to five- or six-membered aromatic ring cores that could present anticholinesterasic activity and additional pharmacological properties. The new compounds were designed as juxtaposed structures between tacrine and the well-known Ca2+ antagonists 1,4-dihydropyridines, with the goal of obtaining multi-target directed ligands for AD. In this account, we present our results on the PyridoTacrine (PyrTac) family of tacrine analogues, resulting from the substitution of the benzene ring by a pyridine. We highlight their pharmacological profile and review similar analogues in the literature. A first set of PyrTac showed inhibitory activity of cholinesterases (ChE) and a blocking profile of voltage-gated Ca2+ channels (VGCC). A second family with improved ChE inhibition lost VGCC blocking activity. However, the lead compound of this family (5f) presented an activating profile of the phosphatase 2A (PP2A) and showed interesting outcomes in experimental in vivo models of AD and stroke. We have identified the PyrTac ethyl 5-amino-2-methyl-6,7,8,9-tetrahydrobenzo[ b ] [1,8]naphthyridine-3-carboxylate (5f), which presents additional pharmacological properties beyond the mere cholinergic improvement. These new properties warrant attention to 5f and its further development as a new potential therapeutic agent for AD therapy. Graphical abstract Image 1 Highlights • Tacrine is a good scaffold to design multitarget drugs for Alzheimer's disease. • Pyridotacrines are derivatives from the replacement of the benzene-fused ring by pyridine. • Pyridotacrines avoid toxic metabolism and allow the design of multitarget compounds. • Among contributions by others, we described several families of Pyridotacrines. • Our compounds presented new biological activities of relevance for Alzheimer's disease. [ABSTRACT FROM AUTHOR]

Graphical abstract The medicinal chemistry and pharmacological properties of the lead molecules of 92 hybrids published since 1998-Dec 2017 have been reviewed. Abstract Alzheimer's disease (AD) is a genetically complex, progressive and irreversible neurodegenerative disorder of the brain which involves multiple associated etiological targets. The complex pathogenesis of AD gave rise to multi-target-directed ligands (MTDLs) principle to combat this dreaded disease. Within this approach, the design and synthesis of hybrids prevailed greatly because of their capability to simultaneously target the intertwined pathogenesis components of the disease. The hybrids include pharmacophoric hybridization of two or more established chemical scaffolds endowed with the desired pharmacological properties into a single moiety. In AD, the primary foundation of medication therapy and drug design strategies includes the inhibition of cholinesterase (ChE) enzymes. Hence the development of ChE inhibition based hybrids is the central choice of AD medicinal chemistry research. To illustrate the progress of ChE inhibition based hybrids and novel targets, we reviewed the medicinal chemistry and pharmacological properties of the multi-target molecules published since 1998-December 2018. We hope that this article will allow the readers to easily follow the evolution of this prominent medicinal chemistry approach to develop a more efficient inhibitor. [ABSTRACT FROM AUTHOR]

Parkinson's disease is a neurodegenerative disorder characterized by the progressive loss of dopaminergic neurons in the midbrain. Current treatments provide limited symptomatic relief without halting disease progression. A multi-targeting approach has shown potential benefits in treating neurodegenerative diseases. In this study, we employed in silico approaches to explore the COCONUT natural products database and identify novel drug candidates with multi-target potential against relevant Parkinson's disease targets. QSAR models were developed to screen for potential bioactive molecules, followed by a hybrid virtual screening approach involving pharmacophore modeling and molecular docking against MAO-B, AA 2A R, and NMDAR. ADME evaluation was performed to assess drug-like properties. Our findings revealed 22 candidates that exhibited the desired pharmacophoric features. Particularly, two compounds: CNP0121426 and CNP0242698 exhibited remarkable binding affinities, with energies lower than -10 kcal/mol and promising interaction profiles with the chosen targets. Furthermore, all the ligands displayed desirable pharmacokinetic properties for brain-targeted drugs. Lastly, molecular dynamics simulations were conducted on the lead candidates, belonging to the dihydrochalcone and curcuminoid class, to evaluate their stability over a 100 ns timeframe and compare their dynamics with reference complexes. Our findings revealed the curcuminoid CNP0242698 to have an overall better stability with the three targets compared to the dihydrochalcone, despite the high ligand RMSD, the curcuminoid CNP0242698 showed better protein stability, implying ligand exploration of different orientations. Similarly, AA 2A R exhibited higher stability with CNP0242698 compared to the reference complex, despite the high initial ligand RMSD due to the bulkier active site. In NMDAR, CNP0242698 displayed good stability and less fluctuations implying a more restricted conformation within the smaller active site of NMDAR. These results may serve as lead compounds for the development and optimization of natural products as multi-target disease-modifying natural remedies for Parkinson's disease patients. However, experimental assays remain necessary to validate these findings.Communicated by Ramaswamy H. Sarma.

Graphical abstract Highlights • Compounds 7f exhibits potent HDAC6 inhibitory activity and ebselen-related pharmacological effects. • Compound 7f has significant protective effects against damage induced by H 2 O 2. • Compound 7f prevents ROS accumulation in PC12 cells. Abstract A series of hybrids containing the pharmacophores of the histone deacetylase (HDAC) inhibitor, SAHA, and the antioxidant ebselen were designed and synthesized as multi-target-directed ligands against Alzheimer's disease. An in vitro assay indicated that some of these molecules exhibit potent HDAC inhibitory activity and ebselen-related pharmacological effects. Specifically, the optimal compound 7f was found to be a potent HDAC inhibitor (IC 50 = 0.037 μM), possessing rapid hydrogen peroxide scavenging activity and glutathione peroxidase-like activity (ν 0 = 150.0 μM min−1) and good free oxygen radical absorbance capacity (value of ORAC: 2.2). Furthermore, compound 7f showed significant protective effects against damage induced by H 2 O 2 and the ability to prevent ROS accumulation in PC12 cells. [ABSTRACT FROM AUTHOR]

Abstract There has been a substantial research effort to design multi-target ligands for the treatment of Alzheimer's disease (AD), an approach that is moved by the knowledge that AD is a complex and multifactorial disease affecting many linked to pathological pathways. Accordingly, we have devoted efforts to develop multi-target ligands based on the chromone scaffold. As a result, a small library of chromone derivatives was synthesized and screened towards human cholinesterases and monoamine oxidases. Compounds 2-(dimethylamino)ethyl (E)-3-(4-oxo-2-(p -methylphenlcarbamoyl)-4 H -chromen-6-yl)acrylate (9a) and 2-(dimethylamino)ethyl (E)-3-(4-oxo-3-(phenylcarbamoyl)-4 H -chromen-6-yl)acrylate (23a) were identified as the most promising multi-target inhibitors of the series. Compound 9a acted as a potent, selective and bifunctional AChEI (IC 50 = 0.21 μM, K i = 0.19 μM) and displayed dual h MAO inhibitory activity (h MAO-A IC 50 = 0.94 μM, K i = 0.057 μM and h MAO-B IC 50 = 3.81 μM, K i = 0.48 μM). Compound 23a acted as a selective IMAO-B (IC 50 = 0.63 μM, K i = 0.34 μM) while still displaying h ChE inhibitory and bifunctional activity in the low micromolar range. Overall, these two compounds stand out as reversible multi-target inhibitors with favourable permeability, toxicological and drug-like profiles, thus being valid candidates for subsequent optimization and pre-clinical studies. Graphical abstract Image 1 Highlights • Successfully BBB permeable chromone-based multi-target compounds targeting human ChEs and MAOs were developed. • Compound 9a acted as a bifunctional h AChE inibitor also possessing dual h MAO inhibitory activity. • Compound 23a acted as a selective h MAO-B inhibitor displaying h ChE inhibitory activity in the low micromolar range. • Compounds showed limited cytotoxicity in differentiated SH-SY5Y and HepG2 cells. [ABSTRACT FROM AUTHOR]

A new series of structurally rigid donepezil analogues was designed, synthesized and evaluated as potential multi-target-directed ligands (MTDLs) against neurodegenerative diseases. The investigated compounds 10 – 13 displayed dual AChE and BACE-1 inhibitory activities in comparison to donepezil, the FDA-approved drug. The hybrid compound 13 bearing 2-aminoquinoline scaffold exhibited potent AChE inhibition (IC 50 value of 14.7 nM) and BACE-1 inhibition (IC 50 value of 13.1 nM). Molecular modeling studies were employed to reveal potential dual binding mode of 13 to AChE and BACE-1. The effect of the investigated compounds on the viability of SH-SY5Y neuroblastoma cells and their ability to cross the blood-brain barrier (BBB) in PAMPA-BBB assay were further studied. [ABSTRACT FROM AUTHOR]

The limited clinical efficacy of current symptomatic treatment and minute effect on progression of Alzheimer's disease has shifted the research focus from single targets towards multi-target-directed ligands. Here, a potent selective inhibitor of human butyrylcholinesterase was used as the starting point to develop a new series of multifunctional ligands. A focused library of derivatives was designed and synthesised that showed both butyrylcholinesterase inhibition and good antioxidant activity as determined by the DPPH assay. The crystal structure of compound 11 in complex with butyrylcholinesterase revealed the molecular basis for its low nanomolar inhibition of butyrylcholinesterase ( Ki  = 1.09 ± 0.12 nM). In addition, compounds 8 and 11 show metal-chelating properties, and reduce the redox activity of chelated Cu 2+ ions in a Cu-ascorbate redox system. Compounds 8 and 11 decrease intracellular levels of reactive oxygen species, and are not substrates of the active efflux transport system, as determined in Caco2 cells. Compound 11 also protects neuroblastoma SH-SY5Y cells from toxic Aβ 1–42 species. These data indicate that compounds 8 and 11 are promising multifunctional lead ligands for treatment of Alzheimer's disease. [ABSTRACT FROM AUTHOR]

Alzheimer’s disease (AD), a complex chronic progressive central nervous system degenerative disease and a public health problem of the world, often characters cognitive dysfunction accompaning aggression and depression, and may lead to death. More attentions should be paid on it because there is no modified strategy against AD till now. AD is featured with the loss of cholinergic neurons, the amyloid-beta peptide (A β ) plaques and the neurofibrillary tangles and several hypotheses were established to explain the pathogenesis of AD. Hydroxycinnamic acids, including caffeic acid (CA) and ferulic acid (FA) are widely distributed in natural plants and fruits. CA and FA exert various pharmacological activities, including anti-inflammatory, antioxidant, neuroprotection, anti-amyloid aggregation and so on. All these pharmacological activities are associated with the treatment of AD. Here we summarized the pharmacological activities of CA and FA, and their hybrids as multi-target-directed ligands (MTDLs) against AD. The future application of CA and FA was also discussed, hoping to provide beneficial information for the development of CA- and FA-based MTDLs against AD. [ABSTRACT FROM AUTHOR]

[Display omitted] • Novel multi-target-directed ligands (MTDLs) against Alzheimer's disease have been developed. • The new hybrids have been obtained by linking tacrines with 4-methylquinoline-2,5,8(1 H)-trione, as juglone replacement. • The most interesting hybrid 3 inhibited cholinesterase enzymes and modulated Aβ self-aggregation. • Hybrid 3 showed antioxidant effects and lower hepatoxicity. Multi-target drug discovery is one of the most active fields in the search for new drugs against Alzheimer's disease (AD). This is because the complexity of AD pathological network might be adequately tackled by multi-target-directed ligands (MTDLs) aimed at modulating simultaneously multiple targets of such a network. In a continuation of our efforts to develop MTDLs for AD, we have been focusing on the molecular hybridization of the acetylcholinesterase inhibitor tacrine with the aim of expanding its anti-AD profile. Herein, we manipulated the structure of a previously developed tacrine-quinone hybrid (1). We designed and synthesized a novel set of MTDLs (2 – 6) by replacing the naphthoquinone scaffold of 1 with that of 2,5,8-quinolinetrione. The most interesting hybrid 3 inhibited cholinesterase enzymes at nanomolar concentrations. In addition, 3 exerted antioxidant effects in menadione-induced oxidative stress of SH-SY5Y cells. Importantly, 3 also showed low hepatotoxicity and good anti-amyloid aggregation properties. Remarkably, we uncovered the potential of the quinolinetrione scaffold, as a novel anti-amyloid aggregation and antioxidant motif to be used in further anti-AD MTDL drug discovery endeavors. [ABSTRACT FROM AUTHOR]

A series of novel compounds with phosphoramide mustard functionality incorporated into the quinazoline scaffold of EGFR/HER2 inhibitors were designed and synthesized as multi-target-directed ligands against tumor cells. In vitro assays showed that tumor cell lines with high HER2 level were more sensitive to the compounds than tumor cells with low HER2 level. Compound 10d (EMB-3) was one of the most potent inhibitors with IC 50 of 7.4 nM and 82 nM against EGFR and HER2, respectively. The mechanism studies were also supported by the effect of 10d -induced DNA damage in MDA-MB-468 cells. In vivo efficacy study showed that 10d could significantly inhibit H522 tumor xenograft model with a TGI of 68% at dose of 100 mg/kg (QDx28, p.o.) and no significant body weight loss was observed. MTD study indicated that compound 10d had no acute toxicity to mice at doses up to 900 mg/kg (single dose). [ABSTRACT FROM AUTHOR]

The development of short-peptide-based inhibitors to prevent HIV-1 entry into the host cell has been rewarded with limited success. Herein, we report a multitarget-directed ligand strategy to generate a series of short-peptide HIV-1 entry inhibitors that integrated the pharmacological activities of a peptide fusion inhibitor able to disrupt HIV-1 gp41 glycoprotein hexameric coiled-coil assembly and a small-molecule CCR5 antagonist that blocks the interaction between HIV-1 and its coreceptor. Among these inhibitors, dual-target 23-residue peptides SP12T and SP12L displayed dramatically increased inhibitory activities against HIV-1 replication as compared to the marketed 36-residue peptide T20. Moreover, results suggested that SP12T and SP12L successfully performed a dual-targeting mechanism. It can be concluded that these short-peptide-based HIV-1 entry inhibitors have potential for further development as candidates for a novel multitarget therapy to treat HIV-1 infection. [Display omitted] • Short peptide HIV entry inhibitors were designed via a multi-target design strategy. • Chimeras were obtained by linking together a CCR5 antagonist and a short-peptide SP22. • Dual-target inhibitors showed improved anti-HIV activity than parental inhibitors. • Dual-target short peptides had dramatically increased anti-HIV potency than T20. [ABSTRACT FROM AUTHOR]

Alzheimer's disease (AD), the most common form of adult onset dementia, is an age-related neurodegenerative disorder characterized by progressive memory loss, decline in language skills and other cognitive impairments. Although its etiology is not completely known, several factors including deficits of acetylcholine, β-amyloid deposits, τ-protein phosphorylation, oxidative stress and neuroinflammation are considered to play significant roles in the pathophysiology of this disease. For a long time, AD patients have been treated with acetylcholinesterase inhibitors such as donepezil (Aricept®) but with limited therapeutic success. This might be due to the complex multifactorial nature of AD, a fact that has prompted the design of new Multi-Target-Directed Ligands (MTDL) based on the one molecule, multiple targets paradigm. Thus, in this context, different series of novel multifunctional molecules with antioxidant, anti-amyloid, anti-inflammatory and metal-chelating properties able to interact with multiple enzymes of therapeutic interest in AD pathology including acetylcholinesterase, butyrylcholinesterase and monoamine oxidases A and B have been designed and assessed biologically. This review describes the multiple targets, the design rationale and an in-house MTDL library, bearing the N-benzylpiperidine motif present in donepezil, linked to different heterocyclic ring systems (indole, pyridine or 8-hydroxyquinoline) with special emphasis on compound ASS234, an N-propargylindole derivative. The description of the in vitro biological properties of the compounds and discussion of the corresponding structure-activity-relationships allows us to highlight new issues for the identification of more efficient MTDL for use in AD therapy.

As currently postulated, a complex treatment may be key to an effective therapy for Alzheimer's disease (AD). Recent clinical trials in patients with moderate AD have shown a superior effect of the combination therapy of donepezil (a selective acetylcholinesterase inhibitor) with idalopirdine (a 5-HT 6 receptor antagonist) over monotherapy with donepezil. Here, we present the first report on the design, synthesis and biological evaluation of a novel class of multifunctional ligands that combines a 5-HT 6 receptor antagonist with a cholinesterase inhibitor. Novel multi-target-directed ligands (MTDLs) were designed by combining pharmacophores directed against the 5-HT 6 receptor (1-(phenylsulfonyl)-4-(piperazin-1-yl)-1 H -indole) and cholinesterases (tacrine or N -benzylpiperidine analogues). In vitro evaluation led to the identification of tacrine derivative 12 with well-balanced potencies against the 5-HT 6 receptor ( K b = 27 nM), acetylcholinesterase and butyrylcholinesterase (IC 50 h AChE = 12 nM, IC 50 h BuChE = 29 nM). The compound also showed good in vitro blood-brain-barrier permeability (PAMPA-BBB assay), which was confirmed in vivo (open field study). Central cholinomimetic activity was confirmed in vivo in rats using a scopolamine-induced hyperlocomotion model. A novel class of multifunctional ligands with compound 12 as the best derivative in a series represents an excellent starting point for the further development of an effective treatment for AD. [ABSTRACT FROM AUTHOR]

A series of benzoates (or phenylacetates or cinnamates) – tacrine hybrids (7 a - o ) were designed, synthesized and evaluated as multi-potent anti-Alzheimer drug candidates. The screening results showed that most of them exhibited a significant ability to inhibit ChEs, certain selectivity for AChE over BuChE and strong potency inhibitory of self-induced β-amyloid (Aβ) aggregation. All IC 50 values of biological activity were at the nanomolar range. Especially, compound 7c displayed the greatest ability to inhibit AChE with an IC 50 value of 5.63 nM and the highest selectivity with ratio of BuChE/AChE value of 64.6. Moreover, it also exhibited a potent inhibitory of Aβ aggregation with an IC 50 value of 51.81 nM. A Lineweaver–Burk plot and molecular modeling study showed that compound 7c targeted both the CAS and PAS of ChEs. A structure–activity relationship analysis suggested that the electron density of aromatic ring which was linked with tacrine through acetyl group played a significant role in determining the inhibitory activity. [ABSTRACT FROM AUTHOR]

Alzheimer's disease (AD), the most common form of adult onset dementia, is an age-related neurodegenerative disorder characterized by progressive memory loss, decline in language skills, and other cognitive impairments. Although its etiology is not completely known, several factors including deficits of acetylcholine, b-amyloid deposits, t-protein phosphorylation, oxidative stress, and neuroinflammation are considered to play significant roles in the pathophysiology of this disease. For a long time, AD patients have been treated with acetylcholinesterase inhibitors such as donepezil (Aricept®) but with limited therapeutic success. This might be due to the complex multifactorial nature of AD, a fact that has prompted the design of new Multi- Target-Directed Ligands (MTDL) based on the "one molecule, multiple targets" paradigm. Thus, in this context, different series of novel multifunctional molecules with antioxidant, anti-amyloid, anti-inflammatory, and metal-chelating properties able to interact with multiple enzymes of therapeutic interest in AD pathology including acetylcholinesterase, butyrylcholinesterase, and monoamine oxidases A and B have been designed and assessed biologically. This review describes the multiple targets, the design rationale and an in-house MTDL library, bearing the N-benzylpiperidine motif present in donepezil, linked to different heterocyclic ring systems (indole, pyridine, or 8-hydroxyquinoline) with special emphasis on compound ASS234, an N-propargylindole derivative. The description of the in vitro biological properties of the compounds and discussion of the corresponding structure-activity-relationships allows us to highlight new issues for the identification of more efficient MTDL for use in AD therapy. [ABSTRACT FROM AUTHOR]

The need for developing real disease-modifying drugs against neurodegenerative syndromes, particularly Alzheimer’s disease (AD), shifted research towards reliable drug discovery strategies to unveil clinical candidates with higher therapeutic efficacy than single-targeting drugs. By following the multi-target approach, we designed and synthesized a novel class of dual acetylcholinesterase (AChE)-monoamine oxidase B (MAO-B) inhibitors through the decoration of the 2H-chromen-2-one skeleton. Compounds bearing a propargylamine moiety at position 3 displayed the highest in vitro inhibitory activities against MAO-B. Within this series, derivative 3h emerged as the most interesting hit compound, being a moderate AChE inhibitor (IC50 = 8.99 μM) and a potent and selective MAO-B inhibitor (IC50 = 2.8 nM). Preliminary studies in human neuroblastoma SH-SY5Y cell lines demonstrated its low cytotoxicity and disclosed a promising neuroprotective effect at low doses (0.1 μM) under oxidative stress conditions promoted by two mitochondrial toxins (oligomycin-A and rotenone). In a Madin-Darby canine kidney (MDCK)II-MDR1 cell-based transport study, Compound 3h was able to permeate the BBB-mimicking monolayer and did not result in a glycoprotein-p (P-gp) substrate, showing an efflux ratio = 0.96, close to that of diazepam. [ABSTRACT FROM AUTHOR]

The multifactorial pathogenesis of Alzheimer’s disease (AD) implicates that multi-target-directed ligands (MTDLs) intervention may represent a promising therapy for AD. Amyloid-β (Aβ) aggregation and oxidative stress, two prominent neuropathological hallmarks in patients, play crucial roles in the neurotoxic cascade of this disease. In the present study, a series of novel (−)-meptazinol–melatonin hybrids were designed, synthesized and biologically characterized as potential MTDLs against AD. Among them, hybrids 7 – 7c displayed higher dual inhibitory potency toward cholinesterases (ChEs) and better oxygen radical absorbance capacity (ORAC) than the parental drugs. Furthermore, compound 7c could effectively inhibit Aβ self-aggregation, showed favorable safety and the blood–brain barrier (BBB) permeability. Therefore, 7c may serve as a valuable candidate that is worthy of further investigations in the treatment of AD. [ABSTRACT FROM AUTHOR]

Alzheimer’s disease is a fatal neurodegenerative disorder with a complex etiology. Because the available therapy brings limited benefits, the effective treatment for Alzheimer’s disease remains the unmet challenge. Our aim was to develop a new series of donepezil-based compounds endowed with inhibitory properties against cholinesterases and β-amyloid aggregation. We designed the target compounds as dual binding site acetylcholinesterase inhibitors with N -benzylamine moiety interacting with the catalytic site of the enzyme and an isoindoline-1,3-dione fragment interacting with the peripheral anionic site of the enzyme. The results of pharmacological evaluation lead us to identify a compound 3b as the most potent and selective human acetylcholinesterase inhibitor ( h AChE IC 50 = 0.361 μM). Kinetic studies revealed that 3b inhibited acetylcholinesterase in non-competitive mode. The result of the parallel artificial membrane permeability assay for the blood–brain barrier indicated that the compound 3b would be able to cross the blood–brain barrier and reach its biological targets in the central nervous system. The selected compound 3b represents a potential lead structure for further development of anti-Alzheimer’s agents. [ABSTRACT FROM AUTHOR]

The presented study describes the synthesis, pharmacological evaluation (AChE and BuChE inhibition, beta amyloid anti-aggregation effect and neuroprotective effect), molecular modeling and crystallographic studies of a novel series of isoindoline-1,3-dione derivatives. The target compounds were designed as dual binding site acetylcholinesterase inhibitors with an arylalkylamine moiety binding at the catalytic site of the enzyme and connected via an alkyl chain to a heterocyclic fragment, capable of binding at the peripheral anionic site of AChE. Among these molecules, compound 15b was found to be the most potent and selective AChE inhibitor (IC 50 Ee AChE = 0.034 μM). Moreover, compound 13b in addition to AChE inhibition (IC 50 EeAChE = 0.219 μM) possesses additional properties, such as the ability to inhibit Aβ aggregation (65.96% at 10 μM) and a neuroprotective effect against Aβ toxicity at 1 and 3 μM. Compound 13b emerges as a promising multi-target ligand for the further development of the therapy for age-related neurodegenerative disorders. [ABSTRACT FROM AUTHOR]

[Display omitted] • 33 novel carbamate-based N -salicyloyl tryptamine derivatives was synthesized for the systematical structure–activity relationship studies. • The BChE inhibition of H327 exceeds that of rivastigmine, and the comprehensive enzyme kinetics study was conducted. • H327 possesses neuroprotection, antioxidation, and anti-neuroinflammation efficacy. • H327 was able to cross the blood–brain barrier in vivo. • H327 could effectively improve scopolamine-induced cognitive impairment. In this work, based on the potential anti-AD molecule previously studied by our group, we continue to introduce different substituents at different positions to improve both drug-like properties and on target activities. 33 N -salicyloyl tryptamine-carbamate hybrids were designed, synthesized and evaluated as cholinesterase inhibitors. H327 was the most potent BChE inhibitor (eq BChE IC 50 = 0.057 ± 0.005 μM), and showed threefold improved inhibitory potency than the positive drug rivastigmine (eq BChE IC 50 = 0.19 ± 0.001 μM). In addition, H327 as a pseudo-irreversible BChE inhibitor was endowed with neuroprotective, antioxidative and anti-neuroinflammatory properties. Cytotoxicity and acute toxicity tests confirmed the safety of compound H327. The pharmacokinetics study showed that compound H327 had a longer T 1/2 time and higher bioavailability than the lead compound 1 g. Compound H327 was able to cross the blood–brain barrier (BBB) in vivo. Moreover, the behavioral tests showed that compound H327 could significantly improve scopolamine-induced cognitive impairment in vivo. Overall, these results demonstrated that compound H327 is a promising multi-target agent for the treatment of AD. [ABSTRACT FROM AUTHOR]

Alzheimer's disease is a chronic and progressive brain neurodegenerative disease affecting over 30 million people globally. Currently, no effective treatment is available due to multiple factors involved in the progression of AD. Given that the numerous AD-related targets in the disease network, the multi-target-directed ligands (MTDLs) strategy are considered as the promising strategy to treat AD. Herein, the multi-target compounds with/without ChEs are in clinical and in progress are reviewed. To further characterize the drug-likeness, and ADME properties are calculated using the Qikprop. This review will provide highlights for the treatment of AD. [Display omitted] • This work reviews multi-target strategies with ChEs inhibition. • This work reviews multi-target strategies without ChEs inhibition. • This work predicts ADME properties of the candidate compounds. [ABSTRACT FROM AUTHOR]

Selective drugs directed at a single biological target often prove ineffective in the treatment of diseases with a complex pathomechanism, e.g. Alzheimer’s disease (AD). This situation prompts researchers to design multi-target-directed ligands (MTDLs), capable of interacting with a number of selected biological targets. The paper outlines the concept of the multi-targetdirected ligand design and examples of its use in the search of a cure for AD. In the knowledgebased approach for designing MTDLs, selective ligands of different targets are combined in one molecule. In the screening-based approach, libraries of compounds are screened against selected targets, which allows one to find molecules with a desirable pharmacological profile. It is also possible to obtain multifunctional ligands by performing optimization of a drug with known side activity and transforming it into the main activity, with a simultaneous decrease or complete removal of the original activity. The type of biological targets and applied MTDL design strategy affect the physicochemical and pharmacokinetic properties of the resulting molecules. AD is a multifactorial neurodegenerative disease of the central nervous system associated with the formation of neurofibrillary tangles within neurons, formed by the hyperphosphorylated τ proteins, and extracellular β-amyloid deposits (senile plaques). Current AD therapy comprises symptomatic drugs that enhance cholinergic neurotransmission or inhibit glutamate receptors. The literature provides numerous examples of compounds which proved in in vitro tests to be multifunctional ligands. Most of them are derivatives of cholinesteraseinhibiting drugs, also capable of inhibiting the aggregation of Aβ and showing neuroprotective effects in Aβ-induced cytotoxicity assays. [ABSTRACT FROM AUTHOR]

In recent years, the multi-target-directed ligand concept has been used to design a variety of molecules hitting different biological targets for Alzheimer's disease. We have sought to combine, in the same molecule, the neuroprotective action of N-methyl- d-aspartate receptor antagonism with the symptomatic relief offered by cholinergic activity through acetylcholinesterase inhibition. This strategy could potentially maintain the positive outcomes of memantine-acetylcholinesterase inhibitor combinations, but with the benefits of a single molecule therapy. Herein, we discuss selected examples of multifunctional compounds, which we rationally designed to simultaneously modulate these targets. We also examine the intertwined relationship between acetylcholinesterase, N-methyl- d-aspartate receptors, and other active players in the neurotoxic cascade. [ABSTRACT FROM AUTHOR]

Abstract: The currently available therapies for Alzheimer’s disease (AD) and related forms of dementia are limited by modest efficacy, adverse side effects, and the fact that they do not prevent the relentless progression of the illness. The purpose of the studies described here was to investigate the neuroprotective effects of the nicotine metabolite cotinine as well as a small series of cotinine and nicotine analogs (including stereoisomers) and to compare their effects to the four clinically prescribed AD therapies. [Copyright &y& Elsevier]