Multi-target-directed ligands to combat neurodegenerative diseases

Novel chimeric peptides of endomorphin-2 and the active fragments of ghrelin exhibit blood-brain barrier permeability and central antinociceptive effects with reduced opioid-related side effects

Pharmacological research has showed that multi-targeted drug therapies offer superior efficacy and reduced side effects compared to single-target drug therapies. In this study, we designed and characterized four novel chimeric peptides G (1-5)-EM2, EM2-G (1-5), G (1-9)-EM2 and EM2-G (1-9) which incorporate endomorphin-2 (EM-2) and the active fragments of ghrelin. Calcium mobilization assays revealed that these four chimeric peptides acted as weak mixed agonists for the μ-opioid receptor (MOR), κ-opioid receptor (KOR), and growth hormone secretagogue receptor 1α (GHS-R1α). The results of fluorescence imaging experiments indicated that G (1-5)-EM2 and G (1-9)-EM2 could penetrate the blood-brain barrier (BBB) following intravenous (i.v.) injection. All chimeric peptides induced almost equal antinociceptive effects compared with EM-2 or better antinociceptive effects than EM-2 after intracerebroventricular (i.c.v.) injection in the acute pain in mice. Among them, G (1-5)-EM2 could cross the BBB and enter the brain to induce antinociceptive effect through central opioid receptors after i. v. Injection. Our findings demonstrated that the chimeric peptides produced significant antinociception mainly via MOR, DOR and GHS-R1α without inducing antinociceptive tolerance, or with a lower tendency for antinociceptive tolerance after i. c.v. Injection in the acute pain in mice. Furthermore, the chimeric peptides mitigated or eliminated the digestive side effects associated with EM-2. The collective results highlight G (1-5)-EM2 as the most promising candidate among the chimeric peptides. The chimeric peptides represent a promising class of potential analgesics for clinical pain management. However, further optimization is necessary to maximize their therapeutic potential.

2-(Phenylamino)-7,8-dihydroquinazolin-5(6H)-one, a promising scaffold for MAO-B inhibitors with potential GSK3β targeting

Neurodegenerative disorders, such as Parkinson's disease and Alzheimer's disease, constitute pathological conditions of great relevance on health span and quality of life. The identification of novel therapeutic options, able to modulate the processes involved in the insurgence and progression of neurodegenerative disorders, represents an intriguing challenge of current research. Herein, a library of 36-membered 2-(phenylamino)-7,8-dihydroquinazolinone derivatives was synthesized and biologically evaluated as human MAO inhibitors. Some compounds able to inhibit MAO-B potently and selectively (Ki in the nanomolar range) were identified, and robust structure-activity relationships were drawn, supported by computational studies. Further biological assays revealed a safe profile for all derivatives and, for compounds selected as the best MAO-B inhibitors (4, 5, 13, 14) the following properties also emerged: (i) the ability to inhibit MAO-B activity in whole cells, with an effectiveness comparable or slight lower with respect to the reference safinamide; (ii) physicochemical parameters suggesting drug-likeness properties; (iii) the ability to inhibit, albeit weakly, GSK3β kinase (for compound 4). Within the whole series, compound 4 stood out as a promising lead for future optimization campaigns aimed to obtain useful drugs for the treatment of Alzheimer's and Parkinson's diseases.

In silico molecular modeling and in vitro biological screening of novel benzimidazole-based piperazine derivatives as potential acetylcholinesterase and butyrylcholinesterase inhibitors

New series of benzimidazole incorporating piperazine moieties in single molecular framework has been reported. The structures of the synthesized derivatives were assigned by 1H-NMR, 13C-NMR, and HR-MS techniques. The hybrid derivatives were evaluated for their acetylcholinesterase and butyrylcholinesterase inhibition effect. All the synthesized analogs showed good to moderate inhibitory effect ranging from IC50 value 0.20 ± 0.01 µM to 0.50 ± 0.10 µM for acetylcholinesterase and from IC50 value 0.25 ± 0.01 µM to 0.70 ± 0.10 µM for butyrylcholinesterase except one that showed least potency with IC50 value 1.05 ± 0.1 µM and 1.20 ± 0.1 µM. The differences in inhibitory potential of synthesized compounds were due to the nature and position of substitution attached to the main ring. Additionally, molecular docking study was carried out for most active in order to explore the binding interactions established by ligand (active compounds) with the active residues of targeted AChE & BuChE enzyme.

Synthesizing Unique Triazolo[3,4-b][1,3,4]Thiadiazines as Effective Anti-Alzheimer's Medications: An In Vitro Study

A new class of triazolo[3,4-b][1,3,4]thiadiazines has been developed by combining thiocarbohydrazide and ethyl cyanoacetate, resulting in the formation of a triazole-3-thione derivative. Afterwards, the compound underwent a reaction with 2-bromoacetamide derivative and chloroacetic acid to yield the corresponding triazolo-thiadiazine derivatives, 6-amino-5-(aminomethyl)-3-methyl-N-(5-methylthiazol-2-yl)-5H-[1,2,4]triazolo[3,4-b][1,3,4]thiadiazine-7-carboxamide derivative and 5-(aminomethyl)-3-methyl-5H-[1,2,4]triazolo[3,4-b][1,3,4]- thiadiazin-6(7H)-one derivative which can serve as a precursor in subsequent processes. Furthermore, when α-bromo ketones were treated with triazole derivative, which was prepared by mixing thiocarbohydrazide with 4-hydroxybenzoic acid, 5H-[1,2,4]triazolo[3,4-b][1,3,4]thiadiazin-3-yl)phenol derivatives were produced. To identify each of the produced compounds, advanced spectroscopic techniques such as mass spectrometry, proton nuclear magnetic resonance (1H NMR), carbon-13 NMR (13C NMR), and Fourier-transform infrared spectroscopy were utilized. Most of the newly generated compounds showed significant inhibitory effects in vitro against the acetylcholinesterase enzyme, making them potential candidates for treating Alzheimer's disease. Two compounds in particular, triazole-3-thione derivative, and 4-(6-(benzofuran-2-yl)-5H-[1,2,4]triazolo[3,4-b][1,3,4]thiadiazin-3-yl)phenol showed the most promising therapeutic potential with IC50 values of 14.58 ± 0.45 and 22.53 ± 0.68 µg/mL, respectively.

Synthesis, Molecular Simulation, DFT, and Kinetic Study of Imidazotriazole-Based Thiazolidinone as Dual Inhibitor of Acetylcholinesterase and Butyrylcholinesterase Enzymes

Background: Alzheimer's disease is a complex and multifactorial brain disorder characterized by gradual memory impairment, cognitive disturbance, and severe dementia, and, ultimately, its progression leads to patient death. This research work presents the design, synthesis, and characterization of novel imidazotriazole-based thiazolidinone derivatives (1-14), displaying promising anti-Alzheimer's activity. Methods: These derivatives were synthesized by using 1H-imidazole-2-thiol as a starting reagent. Structural characterization was accomplished by 13C-NMR and 1H-NMR, while the molecular weight was confirmed by HREI-MS. These compounds were investigated for their anti-Alzheimer's potential under an in vitro analysis. Results: These compounds showed a significant to moderate biological potential against AChE and BChE in comparison to donepezil (IC50 = 8.50 µM and 8.90 µM against AChE and BuChE), used as a reference drug. Among these compounds, analog 10 with IC50 values of 6.70 µM and 7.10 µM against AChE and BuChE emerged as the lead compound of the series with promising biological efficacy against targeted enzymes. Molecular docking revealed the interactive nature of active ligands against target enzymes. These compounds were also assessed under dynamic conditions to examine the structural deviation and conformational changes in a protein complex structure. DFT calculations provided the relative stability and reactivity of the lead compounds. An ADMET analysis showed that these compounds have no toxicological profile. Conclusions: This research study paves the way for the further development and optimization of novel and selective imidazotriazole-based thiazolidinone inhibitors as potent anti-Alzheimer's agents.

Mitochondria-targeted nanovesicles for ursodeoxycholic acid delivery to combat neurodegeneration by ameliorating mitochondrial dysfunction

Mitochondria are pivotal in sustaining oxidative balance and metabolic activity within neurons. It is well-established that mitochondrial dysfunction constitutes a fundamental pathogenic mechanism in neurodegeneration, especially in the context of Parkinson's disease (PD), this represents a promising target for therapeutic intervention. Ursodeoxycholic acid (UDCA), a clinical drug used for liver disease, possesses antioxidant and mitochondrial repair properties. Recently, it has gained attention as a potential therapeutic option for treating various neurodegenerative diseases. However, multiple barriers, including the blood-brain barrier (BBB) and cellular/mitochondrial membranes, significantly hinder the efficient delivery of therapeutic agents to the damaged neuronal mitochondria. Macrophage-derived nanovesicles (NVs), which can traverse the BBB in response to brain inflammation signals, have demonstrated promising tools for brain drug delivery. Nevertheless, natural nanovesicles inherently lack the ability to specifically target mitochondria. Herein, artificial NVs are loaded with UDCA and then functionalized with triphenylphosphonium (TPP) molecules, denoted as UDCA-NVs-TPP. These nanovesicles specifically accumulate in damaged neuronal mitochondria, reduce oxidative stress, and enhance ATP production by 42.62%, thereby alleviating neurotoxicity induced by 1-methyl-4-phenylpyridinium (MPP+). Furthermore, UDCA-loaded NVs modified with TPP successfully cross the BBB and accumulate in the striatum of PD mice. These nanoparticles significantly improve PD symptoms, as demonstrated by a 48.56% reduction in pole climb time, a 59.09% increase in hanging ability, and the restoration of tyrosine hydroxylase levels to normal, achieving remarkable therapeutic efficacy. Our work highlights the immense potential of these potent UDCA-loaded, mitochondria-targeting nanovesicles for efficient treatment of PD and other central neurodegenerative diseases.

Unveiling the multifaceted bioactivity of copper(II)-Schiff base complexes: a comprehensive study of antioxidant, anti-bacterial, anti-inflammatory, enzyme inhibition and cytotoxic potentials with DFT insights

The rise of various diseases demands the development of new agents with antioxidant, antimicrobial, anti-inflammatory, enzyme-inhibiting, and cytotoxic properties. In this study, heterocyclic Schiff base complexes of Cu(II) featuring a benzo[b]thiophene moiety were synthesized and their biological activities evaluated. The complexes were characterized using FT-IR, UV-Vis, and EPR spectroscopy, TG-DTG analysis, magnetic moment measurements, molar conductivity measurements, and elemental analyses. Density functional theory (DFT) calculations were used to optimize the theoretical molecular orbital energies of the copper complexes. The complexes exhibited square pyramidal and square planar geometries. Biological assays demonstrated that these complexes generally outperformed the Schiff base ligands for various activities. The antioxidant capacity, measured via the DPPH assay in methanol, was comparable to those of the BHT and ascorbic acid standards, with 4BNPC showing the lowest IC50 value, which was attributed to the free OH group rather than coordination to the metal center. The anti-bacterial activity was assessed using the agar disc diffusion method against E. coli, P. aeruginosa, B. subtilis, and S. aureus, with BAC showing the largest inhibition zone compared to the others and ciprofloxacin as the reference. The anti-inflammatory activity, evaluated by the HRBC membrane stabilization method, showed that the 4BNPC Cu(II) complex had moderate activity similar to that of diclofenac. Enzyme inhibition studies against α-amylase revealed that the BAC complexes had the highest inhibition values, surpassing those of the Schiff base ligands. Cytotoxicity was assessed using Trypan blue exclusion for DLA and HepG2 cancer cell lines, and the MTT assay for H9c2 human cells. BMPC demonstrated superior cytotoxicity at both high and low concentrations against the normal H9c2 cell line. Among the tested compounds, BNPC showed moderate inhibition against HepG2 cells, while BMPC exhibited the greatest cytotoxicity at higher concentrations, particularly reaching nearly 100% cell death at 200 μg mL-1 in DLA cell lines. This suggests that BMPC is a promising candidate for further pharmacological research, particularly against DLA cells.

Pathway-based network medicine identifies novel natural products for Alzheimer's disease

BACKGROUND

Alzheimer's disease (AD) is the leading cause of dementia, characterized by a complex pathogenesis that complicates the development of effective treatments. Natural products are promising multitarget agents because of their ability to interact with multiple molecular targets. Network-based medicine presents a robust strategy for discovering such agents, which can address the intricate mechanisms underlying AD.

METHODS

In this study, we constructed an AD-related pathway-gene network via text mining and pathway database construction. This network facilitated the identification of natural products that target multiple pathways and genes associated with AD. We evaluated the safety profiles of two selected natural products in C57BL/6J mice through assessments of general behavior, body weight changes, vital organ weight and morphology, and hematological and biochemical parameters. APP/PS1 transgenic mice were subsequently treated with these natural products-either individually or in combination-to assess their therapeutic effects. Cognitive function was evaluated via behavioral tests, such as novel object recognition, Y-maze, and Morris water maze tests. Additionally, immunohistochemical staining and enzyme-linked immunosorbent assays were performed to examine Aβ-associated pathological changes. Transcriptomic analysis and quantitative real-time polymerase chain reaction (qRT-PCR) were employed to elucidate the mechanisms underlying the effects of the natural products.

RESULTS

The constructed AD-related pathway-gene network encompassed three perspectives: (i) Most Studied Pathways (21 pathways with 5325 genes), (ii) Gene-Associated Pathways (26 pathways with 2557 genes), and (iii) Popular Pathways (24 pathways with 3435 genes). Two natural products, (-)-Vestitol and Salviolone, were selected for further validation. Their safety was confirmed in C57BL/6J mice. Notably, the combination of (-)-Vestitol and Salviolone synergistically affected cognitive function in APP/PS1 transgenic mice by reducing Aβ deposition and lowering toxic soluble Aβ levels in the brain. Transcriptomic analysis and qRT-PCR experiments revealed that their combination regulated AD-related pathways and genes more comprehensively, particularly affecting the Neuroactive ligand-receptor interaction and Calcium signaling pathway.

CONCLUSIONS

Our findings demonstrate that screening potential natural products through an AD-related pathway-gene network is a promising strategy for discovering novel therapeutics for AD. The therapeutic potential of (-)-Vestitol and Salviolone as novel candidates for AD treatment is underscored by their synergistic effects, attributed to their comprehensive regulation of AD-associated pathways and genes.

Design, synthesis, and evaluation of novel benzofuran and pyrazole-based derivatives as dual AChE/BuChE inhibitors with antioxidant properties for Alzheimer's disease management

As a complicated neurodegenerative disorder with several clinical hallmarks, Alzheimer's disease (AD) requires multi-target treatment medicines to address multiple elements of disease progression. In this study, we reported two novel series of compounds: benzofuran-based donepezil analogs (9a-i) and their pyrazole-based counterparts (11a-i) as potential dual inhibitors of AChE and BuChE with additional antioxidant properties, aiming to address multiple pathological aspects of AD simultaneously. The design strategy employed bioisosteric replacement, substituting donepezil's indanone motif with a benzofuran ring in series (9a-i) to maintain crucial hydrogen bonding interactions with the Phe295 residue in the enzyme's active site. Subsequently, the benzofuran ring underwent cleavage, yielding pyrazole-tethered hydroxyphenyl derivatives (11a-i). The biological evaluation revealed that benzofuran-based derivative 9g exhibited exceptional efficacy against both AChE and BuChE, with IC50 values of 0.39 and 0.51 μg/ml, respectively, although it lacked antioxidant activity. Compound 11f demonstrated dual inhibition of AChE (IC50 = 1.24 μg/ml) and BuChE (IC50 = 1.85 μg/ml) while also displaying strong DPPH free radical scavenging activity (IC50 = 3.15 μg/ml). In vivo toxicity studies on compound 11f revealed a favorable safety profile, with no signs of toxicity or adverse events in acute oral toxicity tests in male Wistar rats. Chronic administration of 11f resulted in negligible differences in blood profiles, hepatic enzymes, urea, creatinine, and albumin levels compared to the control group. Histopathological examination of hepatic and kidney tissues from treated rats showed normal histology without damage. In silico molecular docking analysis was performed to rationalize the design approaches and support the experimental findings. This study provides valuable insights into the development of multi-target compounds for potential Alzheimer's disease treatment.

Structure-based inhibition of acetylcholinesterase and butyrylcholinesterase with 2-Aryl-6-carboxamide benzoxazole derivatives: synthesis, enzymatic assay, and in silico studies

An important research topic is the discovery of multifunctional compounds targeting different disease-causing components. This research aimed to design and synthesize a series of 2-aryl-6-carboxamide benzoxazole derivatives that inhibit cholinesterases on both the peripheral anionic and catalytic anionic sides. Compounds (7-48) were prepared from 4-amino-3-hydroxybenzoic acid in three steps. The Ellman test, molecular docking with Maestro, and molecular dynamics simulation studies with Desmond were done (Schrodinger, 12.8.117). Compound 36, the most potent compound among the 42 new compounds synthesized, had an inhibitory concentration of IC50 12.62 nM for AChE and IC50 25.45 nM for BChE (whereas donepezil was 69.3 nM and 63.0 nM, respectively). Additionally, compound 36 had docking values ​​of - 7.29 kcal/mol for AChE and - 6.71 kcal/mol for BChE (whereas donepezil was - 6.49 kcal/mol and - 5.057 kcal/mol, respectively). Furthermore, molecular dynamics simulations revealed that compound 36 is stable in the active gorges of both AChE (average RMSD: 1.98 Å) and BChE (average RMSD: 2.2 Å) (donepezil had average RMSD: 1.65 Å and 2.7 Å, respectively). The results show that compound 36 is a potent, selective, mixed-type dual inhibitor of both acetylcholinesterase and butyrylcholinesterase. It does this by binding to both the catalytically active and peripheral anionic sites of cholinesterases at the same time. These findings show that target compounds may be useful for establishing the structural basis for new anti-Alzheimer agents.

Ellagic Acid: A Green Multi-Target Weapon That Reduces Oxidative Stress and Inflammation to Prevent and Improve the Condition of Alzheimer's Disease

Oxidative stress (OS), generated by the overrun of reactive species of oxygen and nitrogen (RONS), is the key cause of several human diseases. With inflammation, OS is responsible for the onset and development of clinical signs and the pathological hallmarks of Alzheimer's disease (AD). AD is a multifactorial chronic neurodegenerative syndrome indicated by a form of progressive dementia associated with aging. While one-target drugs only soften its symptoms while generating drug resistance, multi-target polyphenols from fruits and vegetables, such as ellagitannins (ETs), ellagic acid (EA), and urolithins (UROs), having potent antioxidant and radical scavenging effects capable of counteracting OS, could be new green options to treat human degenerative diseases, thus representing hopeful alternatives and/or adjuvants to one-target drugs to ameliorate AD. Unfortunately, in vivo ETs are not absorbed, while providing mainly ellagic acid (EA), which, due to its trivial water-solubility and first-pass effect, metabolizes in the intestine to yield UROs, or irreversible binding to cellular DNA and proteins, which have very low bioavailability, thus failing as a therapeutic in vivo. Currently, only UROs have confirmed the beneficial effect demonstrated in vitro by reaching tissues to the extent necessary for therapeutic outcomes. Unfortunately, upon the administration of food rich in ETs or ETs and EA, URO formation is affected by extreme interindividual variability that renders them unreliable as novel clinically usable drugs. Significant attention has therefore been paid specifically to multitarget EA, which is incessantly investigated as such or nanotechnologically manipulated to be a potential "lead compound" with protective action toward AD. An overview of the multi-factorial and multi-target aspects that characterize AD and polyphenol activity, respectively, as well as the traditional and/or innovative clinical treatments available to treat AD, constitutes the opening of this work. Upon focus on the pathophysiology of OS and on EA's chemical features and mechanisms leading to its antioxidant activity, an all-around updated analysis of the current EA-rich foods and EA involvement in the field of AD is provided. The possible clinical usage of EA to treat AD is discussed, reporting results of its applications in vitro, in vivo, and during clinical trials. A critical view of the need for more extensive use of the most rapid diagnostic methods to detect AD from its early symptoms is also included in this work.

De novo generation of dual-target compounds using artificial intelligence

Drugs that interact with multiple therapeutic targets are potential high-value products in polypharmacology-based drug discovery, but the rational design remains a formidable challenge. Here, we present artificial intelligence (AI)-based methods to design the chemical structures of compounds that interact with multiple therapeutic target proteins. The molecular structure generation is performed by a fragment-based approach using a genetic algorithm with chemical substructures and a deep learning approach using reinforcement learning with stochastic policy gradients in the framework of generative adversarial networks. Using the proposed methods, we designed the chemical structures of compounds that would interact with two therapeutic targets of bronchial asthma, i.e., adenosine A2a receptor (ADORA2A) and phosphodiesterase 4D (PDE4D). We then synthesized 10 compounds and evaluated their bioactivities via the binding assays of 39 target human proteins, including ADORA2A and PDE4D. Three of the 10 synthesized compounds successfully interacted with ADORA2A and PDE4D with high specificity.

Multipotent Effect of Clozapine on Lipopolysaccharide-Induced Acetylcholinesterase, Cyclooxygenase-2,5-Lipoxygenase, and Caspase-3: In Vivo and Molecular Modeling Studies

Dual inhibition of cyclooxygenase-2 (COX-2) and lipoxygenase (LOX) is a recognized strategy for enhanced anti-inflammatory effects in small molecules, offering potential therapeutic benefits for individuals at risk of dementia, particularly those with neurodegenerative diseases, common cancers, and diabetes type. Alzheimer's disease (AD) is the most common cause of dementia, and the inhibition of acetylcholinesterase (AChE) is a key approach in treating AD. Meanwhile, Caspase-3 catalyzes early events in apoptosis, contributing to neurodegeneration and subsequently AD. Structure-based virtual screening of US-FDA-approved molecules from the ZINC15 database identified clozapine (CLOZ) as the dual inhibitor of COX-2 and AChE, with significant binding affinity. Further molecular docking of CLOZ in the active site of LOX and Caspase-3 also showed significant binding potential. Further, the results from molecular docking were validated using molecular dynamics simulation (MDS) studies, confirming the results from molecular docking. The results from MDS showed good binding potential and interactions with key residues. The CLOZ was further assessed using lipopolysaccharide (LPS)-challenged rats treated for thirty days at doses of 5 and 10 mg/kg, p.o. The results demonstrated modulation of COX-2, 5-LOX, AChE, Caspase-3, and MDA in LPS-induced brains. Additionally, the expression level of IL-10 was also measured. Our results showed a significant decrease in the levels of COX-2, 5-LOX, AChE, Caspase-3, and MDA. Our results also showed a significant decrement in the pro-inflammatory markers NF-κB, TNF-α, and IL-6 and an improvement in the levels of anti-inflammatory markers IL-10 and TGF-β1. Overall, the findings indicate that CLOZ has potential for neuroprotective effects against LPS-treated rats and can be explored.

Neurotoxic Effect of Myricitrin in Copper-Induced Oxidative Stress Is Mediated by Increased Intracellular Ca2+ Levels and ROS/p53/p38 Axis

Although commonly appreciated for their anti-oxidative and neuroprotective properties, flavonoids can also exhibit pro-oxidative activity, potentially reducing cell survival, particularly in the presence of metal ions. Disrupted copper homeostasis is a known contributor to neuronal dysfunction through oxidative stress induction. This study investigated the effects of myricitrin (1-20 μg/mL) on copper-induced toxicity (0.5 mM CuSO4) in the neuroblastoma SH-SY5Y cell line. At non-toxic concentrations, myricitrin exacerbated copper's toxic effects. The myricitrin-induced decrease in survival was accompanied with increased reactive oxygen species (ROS) production, reduced superoxide dismutase activity, and a lower GSH/GSSG ratio. In combination with copper, myricitrin also activated caspase-3/7, promoted nuclear chromatin changes, and compromised membrane integrity. At the protein level, myricitrin upregulated p53 and PUMA expression. The toxic effects of myricitrin were alleviated by the p38 inhibitor SB203580, the intracellular calcium chelator BAPTA-AM, and the NMDA receptor blocker MK-801, highlighting the significant role of the ROS/p53/p38 axis in cell death and the critical involvement of calcium ions in apoptosis induction. The atomic force microscopy was used to assess the surface morphology and nanomechanical properties of SH-SY5Y cells, revealing changes following myricitrin treatment. This research highlights the toxic potential of myricitrin and emphasizes the need for caution when considering flavonoid supplementation in conditions with elevated copper levels.

Multi-target directed ligands inspired natural products as an effective approach for the treatment of complex chronic health disorders

Complex diseases involve multifaceted etiological components, which limit the effectiveness of conventional targeted therapies. Therefore, standard medicinal treatments often face significant challenges and failures when addressing these disease conditions. Furthermore, the growing interest in multidrug resistance (MDR), the occurrence of adverse drug reactions related to use traditional approaches, and the limited clinical efficacy of single-target drug therapy have increased the demand for innovative drug treatments. In this rapidly evolving era, the exploration of multi-target directed ligands (MTDLs) derived from natural products has granted us access to a wide range of compounds with medicinal properties. The allure of these MTDLs lies in their unique ability to minimize side effects from using two medicinal agents, establishing them as the preferred choice for drug developers. MTDLs have been recognized for their extraordinary capacity to collectively hinder multiple pathways implicated in the development of intricate diseases by merging or linking active molecules obtained from these sources. This review delves into promising MTDLs derived from natural products, which modulates diverse biological pathways implicated in complex diseased conditions particularly Alzheimer's disease, diabetes, cardiac disorders and inflammatory conditions.

Novel chimeric peptides based on endomorphins and ghrelin receptor antagonist produced supraspinal antinociceptive effects with reduced acute tolerance in mice

It is widely recognized that developing bi- or multifunctional opioid compounds could offer a valuable approach to pain management with fewer side effects compared to single-target compounds. In this study, we designed and characterized two novel chimeric peptides, EM-1-DLS and EM-2-DLS, incorporating endomorphins (EMs) and the ghrelin receptor antagonist [D-Lys3]-GHRP-6 (DLS). Functional assays demonstrated that EM-1-DLS and EM-2-DLS acted as κ-opioid receptor (κ-OR)-preferring agonists, weak μ-opioid receptors (μ-OR) and ghrelin receptor (GHSR) agonists. Upon intracerebroventricular (i.c.v.) administration in mice, both EM-1-DLS and EM-2-DLS exhibited dose- and time-dependent antinociceptive effects in the tail withdrawal test. EM-1-DLS demonstrated the highest antinociceptive potency among the peptides, with an ED50 approximately 8-fold greater than EM-1, while EM-2-DLS showed comparable effects to EM-2. The antinociceptive actions of EM-1-DLS involved activation of GHS-R1α, μ-OR, and κ-OR, whereas EM-2-DLS acted via GHS-R1α, δ-OR, and κ-OR pathways. Additionally, acute antinociceptive tolerance was investigated, revealing that EM-1-DLS induced a tolerance ratio of 2.33-fold, significantly lower than the 5.19-fold ratio induced by EM-1. Cross-tolerance ratios between the chimeric peptides and EMs ranged from 0.92 to 1.76, indicating reduced tolerance compared to EMs alone. These findings highlight the potential of these chimeric peptides to mitigate pain with diminished tolerance development, suggesting a promising strategy for the development of new analgesic therapies with improved safety profiles.

Hydroxyl chalcone derivative DK02 as a multi-target-directed ligand for Alzheimer's disease: A preclinical study in zebrafish

BACKGROUND AND PURPOSE

Alzheimer's disease (AD) is a widespread neurodegenerative condition characterized by amyloid-beta (Aβ) plaques and tau protein aggregates, leading to significant cognitive decline. Existing treatments primarily offer symptomatic relief, underscoring the urgent need for novel therapies that address multiple AD pathways. This study evaluates the efficacy of DK02, a hydroxyl chalcone derivative, in a scopolamine-induced dementia model in zebrafish, hypothesizing that it targets several neurodegenerative mechanisms simultaneously.

EXPERIMENTAL APPROACH

We employed a blend of experiments, including in silico docking, in vitro enzyme inhibition assays and in vivo zebrafish models, to assess therapeutic effects of DK02. Methods included molecular docking to forecast interaction sites, acetylcholinesterase (AChE) inhibition testing, and various behavioural and histopathological analyses to gauge DK02's cognitive and neuroprotective impacts.

KEY RESULTS

DK02 emerged as a potent AChE inhibitor via virtual screening, and significantly enhanced cognitive functions in zebrafish, by improving memory retention and reducing anxiety-like behaviours. DK02 also displayed strong antioxidant properties, reducing oxidative stress-induced neuronal damage. Histopathological analysis confirmed its neuroprotective effects by showing decreased amyloid plaque burden and mitigated structural brain damage.

CONCLUSION AND IMPLICATIONS

DK02 shows promise as a multi-target-directed ligand for AD, offering a new therapeutic path by simultaneously addressing cholinergic, oxidative and amyloid pathways. Its potential to enhance cognitive functions and curtail neurodegeneration suggests advantages over current symptomatic treatments. Further research into DK02 mechanisms and long-term impacts is essential for its development in AD therapy.

Neuroprotective Assessment of Nutraceutical (Betanin) in Neuroblastoma Cell Line SHSY-5Y: An in-Vitro and in-Silico Approach

The cognitive dysfunction in the brain cause severe pathological consequences such as Alzheimer's disease (AD), Parkinson's disease. The current treatments are cost expensive and also cause negative side effects. Therefore it is inevitable to develop natural phyto-compounds as a drug like molecules to treat neurodegenerative diseases. In this context, we have assayed the neuroprotective effects of betanin, an indole derivative, in the neuroblastoma cell line SHSY-5Y cells. The neuroprotective effect was investigated in the β-amyloid (Aβ) - induced SHSY-5Y cells; betanin (25 µg) protected the SHSY-5Y cells from the toxic effects and maintained the cell viability. Moreover, the acridine orange and ethidum Bromide staining decipher that treatment of betanin in the Aβ-induced SHSY-5Y cells maintain the cell viablity sustainably. The Reactive Oxygen Species (ROS) assay infers that betanin quenches the generation of free radicals progressively in the Aβ-induced SHSY-5Y cells. In addition, the autophagy determination by flow cytometry revealed that betanin induces autophagy to remove the neurodegenerated cells. Further, we examined the docking and simulation patterns with the angiotensin-converting enzyme (ACE), TNF-α converting enzyme (TACE), glycogen synthase kinase 3 (GK3), and acetylcholinesterase enzymes (AChE) and amyloid precursor protein (APP). The insilico docking analysis denotes that betanin had a significant docking score with the target molecules. Thus, from the invitro and insilico studies, betanin strongly inhibit the toxic effects of Aβand protect the cells from degeneration.

Dual-target inhibitors based on acetylcholinesterase: Novel agents for Alzheimer's disease

Alzheimer's disease (AD) is the most common form of dementia among the elderly, accounting for 60 %-70 % of cases. At present, the pathogenesis of this condition remains unclear, but the hydrolysis of acetylcholine (ACh) is thought to play a role. Acetylcholinesterase (AChE) can break down ACh transmission from the presynaptic membrane and stop neurotransmitters' excitatory effect on the postsynaptic membrane, which plays a key role in nerve conduction. Acetylcholinesterase inhibitors (AChEIs) can delay the hydrolysis of acetylcholine (ACh), which represents a key strategy for treating AD. Due to its complex etiology, AD has proven challenging to treat. Various inhibitors and antagonists targeting key enzymes and proteins implicated in the disease's pathogenesis have been explored as potential therapeutic agents. These include Glycogen Synthase Kinase 3β (GSK-3β) inhibitors, β-site APP Cleaving Enzyme (BACE-1) inhibitors, Monoamine Oxidase (MAO) inhibitors, Phosphodiesterase inhibitors (PDEs), N-methyl--aspartic Acid (NMDA) antagonists, Histamine 3 receptor antagonists (H3R), Serotonin receptor subtype 4 (5-HT4R) antagonists, Sigma1 receptor antagonists (S1R) and soluble Epoxide Hydrolase (sEH) inhibitors. The drug development strategy of multi-target-directed ligands (MTDLs) offers unique advantages in the treatment of complex diseases. On the one hand, it can synergistically enhance the therapeutic efficacy of single-target drugs. On the other hand, it can also reduce the side effects. In this review, we discuss the design strategy of dual inhibitors based on acetylcholinesterase and the structure-activity relationship of these drugs.

Discovery of new 4-aminoquinoline derivatives containing an amine or hydroxamic acid terminal as multifunctional agents for the treatment of Alzheimer's disease

Due to the multifactorial nature of Alzheimer's disease (AD), effective multi-targeted directed ligands (MTDLs) are urgently needed for its treatment as single-target drugs currently encounter therapeutic challenges. Two series of new 4-aminoquinoline derivatives containing an amine or hydroxamic acid terminal were designed, synthesized and evaluated for their cholinesterase inhibition, antioxidant and metal-ion chelation properties. Among them, hydroxamic acid-containing compounds 7r and 7f exhibited the best inhibitor activity against acetylcholinesterase (AChE) and butyrylcholinesterase (BuChE), respectively, with the corresponding IC50 values of 0.41 and 1.06 μM, which were superior to those of rivastigmine (IC50 = 5.26, 2.02 μM, respectively). Moreover, compounds 7r and 7f presented excellent ABTS radical scavenging efficiency and selective metal-ion chelation ability such as Cu2+ and Fe2+. Both molecular docking and enzyme kinetic analysis revealed that compound 7r was a mixed-type inhibitor of AChE. Additionally, the ADME prediction indicated that compounds 7r and 7f have suitable pharmacokinetic and drug-like properties. Furthermore, they demonstrated good safety and blood-brain barrier permeability in cytotoxicity assays and in vivo experiments, respectively. These findings strongly suggest that the 4-aminoquinoline derivatives containing a hydroxamic acid terminal have great potential as promising MTDLs for the treatment of AD, opening new avenues for future therapeutic strategies.

Coumarin Derivative Hybrids: Novel Dual Inhibitors Targeting Acetylcholinesterase and Monoamine Oxidases for Alzheimer's Therapy

Multi-target-directed ligands (MTDLs) represent a promising frontier in tackling the complexity of multifactorial pathologies like Alzheimer's disease (AD). The synergistic inhibition of MAO-B, MAO-A, and AChE is believed to enhance treatment efficacy. A novel coumarin-based molecule substituted with O-phenylpiperazine via three- and four-carbon linkers at the 5- and 7-positions, has been identified as an effective MTDL against AD. Employing a medicinal chemistry approach, combined with molecular docking, molecular dynamic simulation, and ΔGbind estimation, two series of derivatives emerged as potent MTDLs: 8-acetyl-7-hydroxy-4-methylcoumarin (IC50: 1.52-4.95 μM for hAChE, 6.97-7.65 μM for hMAO-A) and 4,7-dimethyl-5-hydroxycoumarin (IC50: 1.88-4.76 μM for hMAO-B). They displayed binding free energy (ΔGbind) of -76.32 kcal/mol (11) and -70.12 kcal/mol (12) against AChE and -66.27 kcal/mol (11) and -62.89 kcal/mol (12) against MAO-A. It is noteworthy that compounds 11 and 12 demonstrated efficient binding to both AChE and MAO-A, while compounds 3 and 10 significantly reduced MAO-B and AChE aggregation in vitro. These findings provide structural templates for the development of dual MAO and AChE inhibitors for the treatment of neurodegenerative diseases.

Therapeutic Options in Alzheimer's Disease: From Classic Acetylcholinesterase Inhibitors to Multi-Target Drugs with Pleiotropic Activity

Alzheimer's disease (AD) is a complex/multifactorial brain disorder involving hundreds of defective genes, epigenetic aberrations, cerebrovascular alterations, and environmental risk factors. The onset of the neurodegenerative process is triggered decades before the first symptoms appear, probably due to a combination of genomic and epigenetic phenomena. Therefore, the primary objective of any effective treatment is to intercept the disease process in its presymptomatic phases. Since the approval of acetylcholinesterase inhibitors (Tacrine, Donepezil, Rivastigmine, Galantamine) and Memantine, between 1993 and 2003, no new drug was approved by the FDA until the advent of immunotherapy with Aducanumab in 2021 and Lecanemab in 2023. Over the past decade, more than 10,000 new compounds with potential action on some pathogenic components of AD have been tested. The limitations of these anti-AD treatments have stimulated the search for multi-target (MT) drugs. In recent years, more than 1000 drugs with potential MT function have been studied in AD models. MT drugs aim to address the complex and multifactorial nature of the disease. This approach has the potential to offer more comprehensive benefits than single-target therapies, which may be limited in their effectiveness due to the intricate pathology of AD. A strategy still unexplored is the combination of epigenetic drugs with MT agents. Another option could be biotechnological products with pleiotropic action, among which nosustrophine-like compounds could represent an attractive, although not definitive, example.

β-d-Ribofuranose as a Core with a Phosphodiester Moiety as the Enzyme Recognition Site for Codrug Development

An ideal codrug design should be able to control drug release, offer selectivity during drug delivery, and break down into non-toxic fragments after biodegradation. Our design incorporates d-ribofuranose as the core, with carbamate and carbonate groups as linking joints, a phosphodiester moiety as an enzyme recognition site, and lenalidomide and paclitaxel as the constituent drugs. The codrug synthesis involves seven steps with a 33% overall yield. The target codrug increases its water solubility 685 times versus paclitaxel.

Sertraline as a Multi-Target Modulator of AChE, COX-2, BACE-1, and GSK-3β: Computational and In Vivo Studies

Alzheimer's disease (AD) is a neurodegenerative disorder associated with the dysregulation of several key enzymes, including acetylcholinesterase (AChE), cyclooxygenase-2 (COX-2), glycogen synthase kinase 3β (GSK-3β), β-site amyloid precursor protein cleaving enzyme 1 (BACE-1), and caspase-3. In this study, machine learning algorithms such as Random Forest (RF), Gradient Boost (GB), and Extreme Gradient Boost (XGB) were employed to screen US-FDA approved drugs from the ZINC15 database to identify potential dual inhibitors of COX-2 and AChE. The models were trained using molecules obtained from the ChEMBL database, with 5039 molecules for AChE and 3689 molecules for COX-2. Specifically, 1248 and 3791 molecules were classified as active and inactive for AChE, respectively, while 858 and 2831 molecules were classified as active and inactive for COX-2. The three machine learning models achieved prediction accuracies ranging from 92% to 95% for both AChE and COX-2. Virtual screening of US-FDA drugs from the ZINC15 database identified sertraline (SETL) as a potential dual inhibitor of AChE and COX-2. Further docking studies of SETL in the active sites of AChE and COX-2, as well as BACE-1, GSK-3β, and caspase-3, revealed strong binding affinities for all five proteins. In vivo validation was conducted using a lipopolysaccharide (LPS)-induced rat model pretreated with SETL for 30 days. The results demonstrated a significant decrease in the levels of AChE (p < 0.001), BACE-1 (p < 0.01), GSK-3β (p < 0.05), and COX-2 (p < 0.05). Additionally, the downstream effects were evaluated, showing significant decreases in the apoptosis marker caspase-3 (p < 0.05) and the oxidative stress marker malondialdehyde (MDA) (p < 0.001), indicating that SETL is clinically localized in its effectiveness, mitigating both enzymatic activity and the associated pathological changes of cognitive impairment and AD.

Role and Interplay of Different Signaling Pathways Involved in Sciatic Nerve Regeneration

Regeneration of the sciatic nerve is a sophisticated process that involves the interplay of several signaling pathways that orchestrate the cellular responses critical to regeneration. Among the key pathways are the mitogen-activated protein kinase (MAPK), phosphatidylinositol 3-kinase (PI3K)/AKT, cyclic adenosine monophosphate (cAMP), and Janus kinase/signal transducers and transcription activators (JAK/STAT) pathways. In particular, the cAMP pathway modulates neuronal survival and axonal regrowth. It influences various cellular behaviors and gene expression that are essential for nerve regeneration. MAPK is indispensable for Schwann cell differentiation and myelination, whereas PI3K/AKT is integral to the transcription, translation, and cell survival processes that are vital for nerve regeneration. Furthermore, GTP-binding proteins, including those of the Ras homolog gene family (Rho), regulate neural cell adhesion, migration, and survival. Notch signaling also appears to be effective in the early stages of nerve regeneration and in preventing skeletal muscle fibrosis after injury. Understanding the intricate mechanisms and interactions of these pathways is vital for the development of effective therapeutic strategies for sciatic nerve injuries. This review underscores the need for further research to fill existing knowledge gaps and improve therapeutic outcomes.

Novel pyrrole based triazole moiety as therapeutic hybrid: synthesis, characterization and anti-Alzheimer potential with molecular mechanism of protein ligand profile

As a springboard to explore novel potent inhibitors of cholinesterase enzymes (AChE and BChE) responsible for causing Alzheimer disorder, the current study was conducted to synthesize pyrrole derived triazole based Schiff base scaffolds by facile synthetic route. These compounds were validated by 1HNMR, 13CNMR and HREI-MS. All these scaffolds (1-16) were examined for their inhibitory activity against AChE and BChE in contrast to Donepezil (10.20 ± 0.10 and 10.80 ± 0.20 µM) and Allanzanthone (12.40 ± 0.10 and 13.10 ± 0.10 µM). All pyrrole derived triazole based Schiff base scaffolds (1-16) showed varied range of inhibitory potentials against acetylcholinesterase and butyrylcholinesterase enzymes with lowest inhibition concentration values ranging from 5.10 ± 0.40-27.10 ± 0.10 µM (for AChE) and 5.60 ± 0.30-28.40 ± 0.30 µM (for BChE). SAR analysis of these derivatives revealed analog 7 as lead molecule against targeted enzyme, while analog 6 and 11 were ranked as second and third most potent scaffolds. Binding affinity and selectivity of potent molecules against targeted enzymes were examined by molecular docking and obtained results showed that potent molecule have versatile significant binding interactions with stated enzymes. Furthermore, safety profiles of potent analogues were predicted via ADMET protocols.

Advances in drug design and therapeutic potential of selective or multitarget 5-HT1A receptor ligands

5-HT1A receptor (5-HT1A-R) is a serotoninergic G-protein coupled receptor subtype which contributes to several physiological processes in both central nervous system and periphery. Despite being the first 5-HT-R identified, cloned and studied, it still represents a very attractive target in drug discovery and continues to be the focus of a myriad of drug discovery campaigns due to its involvement in numerous neuropsychiatric disorders. The structure-activity relationship studies (SAR) performed over the last years have been devoted to three main goals: (i) design and synthesis of 5-HT1A-R selective/preferential ligands; (ii) identification of 5-HT1A-R biased agonists, differentiating pre- versus post-synaptic agonism and signaling cellular mechanisms; (iii) development of multitarget compounds endowed with well-defined poly-pharmacological profiles targeting 5-HT1A-R along with other serotonin receptors, serotonin transporter (SERT), D2-like receptors and/or enzymes, such as acetylcholinesterase and phosphodiesterase, as a promising strategy for the management of complex psychiatric and neurodegenerative disorders. In this review, medicinal chemistry aspects of ligands acting as selective/preferential or multitarget 5-HT1A-R agonists and antagonists belonging to different chemotypes and developed in the last 7 years (2017-2023) have been discussed. The development of chemical and pharmacological 5-HT1A-R tools for molecular imaging have also been described. Finally, the pharmacological interest of 5-HT1A-R and the therapeutic potential of ligands targeting this receptor have been considered.

Phytoactive drugs used in the treatment of Alzheimer's disease and dementia

The prevalence of Alzheimer's disease and other forms of dementia is increasing worldwide, and finding effective treatments for these conditions is a major public health challenge. Natural bioactive drugs have been identified as a promising source of potential treatments, due to their ability to target multiple pathways and their low toxicity. This paper reviews the current state of research on natural bioactive drugs used in the treatment of Alzheimer's disease and other dementias. The paper summarizes the findings of studies on various natural compounds, including curcumin, resveratrol, caffeine, genistein, quercetin, GinkoBiloba, Withaniasomnifera, Ginseng Brahmi, Giloy, and huperzine, and their effects on cognitive function, neuroinflammation, and amyloid-beta accumulation. In this review, we discuss the mechanism of action involved in the treatment of Alzheimer's disease. The paper also discusses the challenges associated with developing natural bioactive drugs for dementia treatment, including issues related to bioavailability and standardization. Finally, the paper suggests directions for future research in this area, including the need for more rigorous clinical trials and the development of novel delivery systems to improve the efficacy of natural bioactive drugs. Overall, this review highlights the potential of natural bioactive drugs as a promising avenue for the development of safe and effective treatments for Alzheimer's disease and other dementias.

An insight into allele-selective approaches to lowering mutant huntingtin protein for Huntington's disease treatment

Huntington's disease (HD), a monogenic neurodegenerative disorder, stems from a CAG repeat expansion within the mutant huntingtin gene (HTT). This leads to a detrimental gain-of-function of the mutated huntingtin protein (mHTT). As of now, there exist no efficacious therapies to alter the disease progression. In view of the monogenetic mutation nature and an indispensable role of wild-type HTT in healthy neurodevelopment and cellular functions, the developing strategy of allele-selectively deleting/silencing mutant HTT as well as only inactivating mHTT without altering wild-type HTT or wild-type huntingtin protein (wtHTT) comes highly recommended, and may offer a promising treatment option for HD. Here, we reviewed the therapeutic approaches that allele-selective lowering mHTT expression by targeting only mutant HTT DNA, RNA and mHTT along with recent preclinical and clinical outcomes and challenges, in anticipation of some novel ideas to be introduced into HD therapeutic research.

Combining Data-Driven and Structure-Based Approaches in Designing Dual PARP1-BRD4 Inhibitors for Breast Cancer Treatment

Poly(ADP-ribose) polymerase 1 (PARP1) inhibitors have revolutionized the treatment of many cancers with DNA-repairing deficiencies via synthetic lethality. Advocated by the polypharmacology concept, recent evidence discovered that a significantly synergistic effect in increasing the death of cancer cells was observed by simultaneously perturbating the enzymatic activities of bromodomain-containing protein 4 (BRD4) and PARP1. Here, we developed a novel cheminformatics approach combined with a structure-based method aiming to facilitate the design of dual PARP1-BRD4 inhibitors. Instead of linking pharmacophores, the developed approach first identified merged pharmacophores (a pool of amide-containing ring systems), from which phenanthridin-6(5H)-one was further prioritized. Based on this starting point, several small molecules were rationally designed, among which HF4 exhibited low micromolar inhibitory activity against BRD4 and PARP1, particularly exhibiting strong inhibition of BRD4 BD1 with an IC50 value of 204 nM. Furthermore, it demonstrated potent antiproliferative effects against breast cancer gene-deficient and proficient breast cancer cell lines by arresting cell cycle progression and impeding DNA damage repair. Collectively, our systematic efforts to design lead-like molecules have the potential to open doors for the exploration of dual PARP1-BRD4 inhibitors as a promising avenue for breast cancer treatment. Furthermore, the developed approach can be extended to systematically design inhibitors targeting PARP1 and other related targets.

Synthesis and Biological Activity Assessment of 2-Styrylbenzothiazoles as Potential Multifunctional Therapeutic Agents

A current trend in healthcare research is to discover multifunctional compounds, able to interact with multiple biological targets, in order to simplify multi-drug therapies and improve patient compliance. The aim of this work was to outline the growing demand for innovative multifunctional compounds, achieved through the synthesis, characterisation and SAR evaluation of a series of 2-styrylbenzothiazole derivatives. The six synthesised compounds were studied for their potential as photoprotective, antioxidant, antiproliferative, and anti-inflammatory agents. In order to profile antioxidant activity against various radical species, in vitro DPPH, FRAP and ORAC assays were performed. UV-filtering activity was studied, first in solution and then in formulation (standard O/W sunscreen containing 3% synthesised molecules) before and after irradiation. Compound BZTst6 proved to be photostable, suitable for broad-spectrum criteria, and is an excellent UVA filter. In terms of antioxidant activity, only compound BZTst4 can be considered a promising candidate, due to the potential of the catechol moiety. Both also showed exceptional inhibitory action against the pro-inflammatory enzyme 5-lipoxygenase (LO), with IC50 values in the sub-micromolar range in both activated neutrophils and under cell-free conditions. The results showed that the compounds under investigation are suitable for multifunctional application purposes, underlining the importance of their chemical scaffolding in terms of different biological behaviours.

Novel multitarget directed ligands inspired by riluzole: A serendipitous synthesis of substituted benzo[b][1,4]thiazepines potentially useful as neuroprotective agents

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.

Design of Multi-Target drugs of HDACs and other Anti-Alzheimer related Targets: Current strategies and future prospects in Alzheimer's diseases therapy

Alzheimer disease (AD) is the most prevalent form of dementia that develops spontaneously in the elderly. It's worth mentioning that as people age, the epigenetic profile of the central nervous system cells changes, which may speed up the development of various neurodegenerative disorders including AD. Histone deacetylases (HDACs) are a class of epigenetic enzymes that can control gene expression without altering the gene sequence. Moreover, a promising strategy for multi-target hybrid design was proposed to potentially improve drug efficacy and reduce side effects. These hybrids are monocular drugs that contain various pharmacophore components and have the ability to bind to different targets at the same time. The HDACs ability to synergistically boost the performance of other anti-AD drugs, as well as the ease with which HDACs inhibitor cap group, can be modified. This has prompted numerous medicinal chemists to design a novel generation of HDACs multi-target inhibitors. Different HDACs inhibitors and other ones such as acetylcholinesterase, butyryl-cholinesterase, phosphodiesterase 9, phosphodiesterase 5 or glycogen synthase kinase 3β inhibitors were merged into hybrids for treatment of AD. This review goes over the scientific rationale for targeting HDACs along with several other crucial targets in AD therapy. This review presents the latest hybrids of HDACs and other AD target pharmacophores.

Design, classification, and adverse effects of NSAIDs: A review on recent advancements

Inflammation is a hallmark of many diseases, including cancer, neurodegenerative diseases like Alzheimer's, type II diabetes, rheumatoid arthritis, and asthma. Nonsteroidal anti-inflammatory drugs (NSAIDs) have been a cornerstone in the management of various inflammatory, pain, and fever-related conditions. As a result, NSAIDs have found their applications in new therapeutic areas. NSAIDs are known to act by inhibiting the cyclooxygenase (COX) pathway. In recent years, new strategies have been proposed to counter inflammation and develop safer COX inhibitors. This review discusses the design of new COX inhibitors, the derivatization of conventional NSAIDs, and their biological applications. The review also presents an integrated classification of NSAIDs incorporating both traditional chemical-based and function-based approaches, including a brief overview of the NSAIDs of natural origins. Additionally, the review addresses adverse effects associated with different NSAIDs, including effects associated with cardiovascular, renal, and hepatic complications emphasizing the need for the development of new and safer COX inhibitors.

Intrathecal administration of MCRT produced potent antinociception in chronic inflammatory pain models via μ-δ heterodimer with limited side effects

An important goal in the opioid field is to discover effective analgesic drugs with minimal side effects. MCRT demonstrated potent antinociceptive effects with limited side effects, making it a promising candidate. However, its pharmacological properties and how it minimizes side effects remain unknown. Various mouse pain and opioid side effect models were used to evaluate the antinociceptive properties and safety at the spinal level. The targets of MCRT were identified through cAMP measurement, isolated tissue assays, and pharmacological experiments. Immunofluorescence was employed to visualize protein expression. MCRT displayed distinct antinociceptive effects between acute and chronic inflammatory pain models due to its multifunctional properties at the μ opioid receptor (MOR), µ-δ heterodimer (MDOR), and neuropeptide FF receptor 2 (NPFFR2). Activation of NPFFR2 reduced MOR-mediated antinociception, leading to bell-shaped response curves in acute pain models. However, activation of MDOR produced more effective antinociception in chronic inflammatory pain models. MCRT showed limited tolerance and opioid-induced hyperalgesia in both acute and chronic pain models and did not develop cross-tolerance to morphine. Additionally, MCRT did not exhibit addictive properties, gastrointestinal inhibition, and effects on motor coordination. Mechanistically, peripheral chronic inflammation or repeated administration of morphine and MCRT induced an increase in MDOR in the spinal cord. Chronic administration of MCRT had no apparent effect on microglial activation in the spinal cord. These findings suggest that MCRT is a versatile compound that provides potent antinociception with minimal opioid-related side effects. MDOR could be a promising target for managing chronic inflammatory pain and addressing the opioid crisis.

Enhanced Recognition Memory through Dual Modulation of Brain Carbonic Anhydrases and Cholinesterases

This study introduces a novel multitargeting strategy that combines carbonic anhydrase (CA) activators and cholinesterase (ChE) inhibitors to enhance cognitive functions. A series of tacrine-based derivatives with amine/amino acid moieties were synthesized and evaluated for their dual activity on brain CA isoforms and ChEs (AChE and BChE). Several derivatives, notably compounds 26, 30, 34, and 40, demonstrated potent CA activation, particularly of hCA II and VII, and strong ChE inhibition with subnanomolar to low nanomolar IC50 values. In vivo studies using a mouse model of social recognition memory showed that these derivatives significantly improved memory consolidation at doses 10-100 times lower than the reference compounds (either alone or in combination). Molecular modeling and ADMET predictions elucidated the compound binding modes and confirmed favorable pharmacokinetic and safety profiles. The findings suggest that dual modulation of CA and ChE activities is a promising strategy for treating cognitive deficits associated with neurodegenerative and psychiatric disorders.

Recent development and strategies towards target interactions: Synthesis, characterization and in silico analysis of benzimidazole based thiadiazole as potential anti-Alzheimer agents

In the current research study, we aim to design and synthesize highly potent hybrid analogs of benzimidazole derived thiadiazole based Schiff base derivatives which can combat the cholinesterase enzymes (acetylcholinesterase and butyrylcholinesterase) accountable for developing Alzheimer's disease. In this context, we have synthesized 15 analogs of benzimidazole based thiadiazole derivatives, which were subsequently confirmed through spectroscopic techniques including 1H NMR, 13C NMR and HREI-MS. Biological investigation of all the analogs revealed their varied acetylcholinesterase inhibitory potency covering a range between 3.20 ± 0.10 μM to 20.50 ± 0.20 μM as well as butyrylcholinesterase inhibitory potential with a range of 4.30 ± 0.50 μM to 20.70 ± 0.50 μM when compared with the standard drug Donepezil having IC50 = 6.70 ± 0.20 μM for AChE and 7.90 ± 0.10 μM for BuChE. The promising inhibition by the analogs was evaluated in SAR analysis, where analog-1 (IC50 = 3.20 ± 0.10 μM for AChE and 4.30 ± 0.50 μM for BuChE), analog-4 (IC50 = 4.30 ± 0.30 μM for AChE and 5.50 ± 0.20 μM for BuChE) and analog-5 (IC50 = 4.10 ± 0.30 μM for AChE and 4.60 ± 0.40 μM for BuChE) were found as the lead candidates. Moreover, molecular docking and ADME analysis were conducted to explore the better binding interactions and drugs likeness respectively.

Synthesis, biological and computational evaluation of benzoxazole hybrid analogs as potential anti-Alzheimer's agents

Aim: Current study aims exploration of bis-benzoxazole bearing bis-Schiff base scaffolds (1-16) as anti-Alzheimer's agents.Materials & methods: 2-aminophenol is used as starting materials which react with different reagents in different step to give us bis-benzoxazole bearing bis-Schiff base analogs. NMR and HREI-MS techniques were used for characterization. All derivatives demonstrated varied range of activities with IC50 values 1.10 ± 0.40-24.50 ± 0.90 μM against acetylcholinesterase (AChE) and 1.90 ± 0.70-28.60 ± 0.60 μM against butyrylcholinesterase (BuChE) in contrast to donepezil. In both cases, analog-3 was found most potent. Molecular docking explored modes of interactions between scaffolds and receptor sites of targeted enzymes.Conclusion: This study offering promising approach for optimization and development of potent inhibitors of cholinesterase enzymes.

New insights into butyrylcholinesterase: Pharmaceutical applications, selective inhibitors and multitarget-directed ligands

Butyrylcholinesterase (BChE), also known as pseudocholinesterase and serum cholinesterase, is an isoenzyme of acetylcholinesterase (AChE). It mediates the degradation of acetylcholine, especially under pathological conditions. Proverbial pharmacological applications of BChE, its mutants and modulators consist of combating Alzheimer's disease (AD), influencing multiple sclerosis (MS), addressing cocaine addiction, detoxifying organophosphorus poisoning and reflecting the progression or prognosis of some diseases. Of interest, recent reports have shed light on the relationship between BChE and lipid metabolism. It has also been proved that BChE is going to increase abnormally as a compensator for AChE in the middle and late stages of AD, and BChE inhibitors can alleviate cognitive disorders and positively influence some pathological features in AD model animals, foreboding favorable prospects and potential applications. Herein, the selective BChE inhibitors and BChE-related multitarget-directed ligands published in the last three years were briefly summarized, along with the currently known pharmacological applications of BChE, aiming to grasp the latest research directions. Thereinto, some emerging strategies for designing BChE inhibitors are intriguing, and the modulators based on target combination of histone deacetylase and BChE against AD is unprecedented. Furthermore, the involvement of BChE in the hydrolysis of ghrelin, the inhibition of low-density lipoprotein (LDL) uptake, and the down-regulation of LDL receptor (LDLR) expression suggests its potential to influence lipid metabolism disorders. This compelling prospect likely stimulates further exploration in this promising research direction.

Advances in dual-targeting inhibitors of HDAC6 for cancer treatment

Histone Deacetylase 6 (HDAC6) is an essential regulator of histone acetylation processes, exerting influence on a multitude of cellular functions such as cell motility, endocytosis, autophagy, apoptosis, and protein trafficking through its deacetylation activity. The significant implications of HDAC6 in diseases such as cancer, neurodegenerative disorders, and immune disorders have motivated extensive investigation into the development of specific inhibitors targeting this enzyme for therapeutic purposes. Single targeting drugs carry the risk of inducing drug resistance, thus prompting exploration of dual targeting therapy which offers the potential to impact multiple signaling pathways simultaneously, thereby lowering the likelihood of resistance development. While pharmacological studies have exhibited promise in combined therapy involving HDAC6, challenges related to potential drug interactions exist. In response to these challenges, researchers are investigating HDAC6 hybrid molecules which enable the concomitant targeting of HDAC6 and other key proteins, thus enhancing treatment efficacy while mitigating side effects and reducing the risk of resistance compared to traditional combination therapies. The published design strategies for dual targeting inhibitors of HDAC6 are summarized and discussed in this review. This will provide some valuable insights into more novel HDAC6 dual targeting inhibitors to meet the urgent need for innovative therapies in oncology and other related fields.

Alzheimer's disease approaches - Focusing on pathology, biomarkers and clinical trial candidates

The strategy for the development of new drugs for Alzheimer's disease (AD) recognizes that an effective therapy requires early therapeutic intervention and a multifactorial approach that considers the individual initiators of AD development. Current knowledge of AD includes the understanding of pathophysiology, risk factors, biomarkers, and the evolving patterns of biomarker abnormalities. This knowledge is essential in identifying potential molecular targets for new drug development. This review summarizes promising AD drug candidates, many of which are currently in phase 2 or 3 clinical trials. New agents are classified according to the Common Alzheimer's Disease Research Ontology (CADRO). The main targets of new drugs for AD are processes related to amyloid beta and tau neurotoxicity, neurotransmission, inflammation, metabolism and bioenergetics, synaptic plasticity, and oxidative stress. These interventions are aimed at preventing disease onset and slowing or eliminating disease progression. The efficacy of pharmacotherapy may be enhanced by combining these drugs with other treatments, antioxidants, and dietary supplements. Ongoing research into AD pathophysiology, risk factors, biomarkers, and the dynamics of biomarker abnormalities may contribute to the understanding of AD and offer hope for effective therapeutic strategies in the near future.

Design, Synthesis, and Biological Evaluation of Ferulic Acid-Piperazine Derivatives Targeting Pathological Hallmarks of Alzheimer's Disease

Alzheimer's disease (AD) is the most prevalent cause of dementia and is characterized by low levels of acetyl and butyrylcholine, increased oxidative stress, inflammation, accumulation of metals, and aggregations of Aβ and tau proteins. Current treatments for AD provide only symptomatic relief without impacting the pathological hallmarks of the disease. In our ongoing efforts to develop naturally inspired novel multitarget molecules for AD, through extensive medicinal chemistry efforts, we have developed 13a, harboring the key functional groups to provide not only symptomatic relief but also targeting oxidative stress, able to chelate iron, inhibiting NLRP3, and Aβ1-42 aggregation in various AD models. 13a exhibited promising anticholinesterase activity against AChE (IC50 = 0.59 ± 0.19 μM) and BChE (IC50 = 5.02 ± 0.14 μM) with excellent antioxidant properties in DPPH assay (IC50 = 5.88 ± 0.21 μM) over ferulic acid (56.49 ± 0.62 μM). The molecular docking and dynamic simulations further corroborated the enzyme inhibition studies and confirmed the stability of these complexes. Importantly, in the PAMPA-BBB assay, 13a turned out to be a promising molecule that can efficiently cross the blood-brain barrier. Notably, 13a also exhibited iron-chelating properties. Furthermore, 13a effectively inhibited self- and metal-induced Aβ1-42 aggregation. It is worth mentioning that 13a demonstrated no symptom of cytotoxicity up to 30 μM concentration in PC-12 cells. Additionally, 13a inhibited the NLRP3 inflammasome and mitigated mitochondrial-induced reactive oxygen species and mitochondrial membrane potential damage triggered by LPS and ATP in HMC-3 cells. 13a could effectively reduce mitochondrial and cellular reactive oxygen species (ROS) in the Drosophila model of AD. Finally, 13a was found to be efficacious in reversing memory impairment in a scopolamine-induced AD mouse model in the in vivo studies. In ex vivo assessments, 13a notably modulates the levels of superoxide, catalase, and malondialdehyde along with AChE and BChE. These findings revealed that 13a holds promise as a potential candidate for further development in AD management.

Unveiling the potential of novel indol-3-yl-phenyl allylidene hydrazine carboximidamide derivatives as AChE/BACE 1 dual inhibitors: a combined in silico, synthesis and in vitro study

Considering the failure of many enzyme inhibitors for Alzheimer's disease (AD), research is now focused on multi-target directed drug discovery. In this paper, inhibition of two essential enzymes implicated in AD pathologies, acetylcholinesterase (AChE) and BACE 1 (Beta-site APP Cleaving Enzyme), has been explored. Taking clues from our previous work, 41 novel indol-3-yl phenyl allylidene hydrazine carboximidamide derivatives were synthesized. The results indicated that compounds inhibited both enzymes in micromolar concentrations. Compound 1l is proposed as the most active. In silico, it was seen to occupy the binding pocket of AChE and BACE 1. The ADME predictions showed that these compounds have acceptable physicochemical characteristics. This study provides new leads for the assessment of AChE and BACE 1 dual inhibition as a promising strategy for AD treatment.

Stepwise Structural Simplification of the Dihydroxyanthraquinone Moiety of a Multitarget Rhein-Based Anti-Alzheimer Lead to Improve Drug Metabolism and Pharmacokinetic Properties

Multitarget compounds have emerged as promising drug candidates to cope with complex multifactorial diseases, like Alzheimer's disease (AD). Most multitarget compounds are designed by linking two pharmacophores through a tether chain (linked hybrids), which results in rather large molecules that are particularly useful to hit targets with large binding cavities, but at the expense of suffering from suboptimal physicochemical/pharmacokinetic properties. Molecular size reduction by removal of superfluous structural elements while retaining the key pharmacophoric motifs may represent a compromise solution to achieve both multitargeting and favorable physicochemical/PK properties. Here, we report the stepwise structural simplification of the dihydroxyanthraquinone moiety of a rhein-huprine hybrid lead by hydroxy group removal-ring contraction-ring opening-ring removal, which has led to new analogs that retain or surpass the potency of the lead on its multiple AD targets while exhibiting more favorable drug metabolism and pharmacokinetic (DMPK) properties and safety profile. In particular, the most simplified acetophenone analog displays dual nanomolar inhibition of human acetylcholinesterase and butyrylcholinesterase (IC50 = 6 nM and 13 nM, respectively), moderately potent inhibition of human BACE-1 (48% inhibition at 15 µM) and Aβ42 and tau aggregation (73% and 68% inhibition, respectively, at 10 µM), favorable in vitro brain permeation, higher aqueous solubility (18 µM) and plasma stability (100/96/86% remaining in human/mouse/rat plasma after 6 h incubation), and lower acute toxicity in a model organism (zebrafish embryos; LC50 >> 100 µM) than the initial lead, thereby confirming the successful lead optimization by structural simplification.

Novel multifunctional tacrine-donepezil hybrids against Alzheimer's disease: Design synthesis and bioactivity studies

A series of tacrine-donepezil hybrids were synthesized as potential multifunctional anti-Alzheimer's disease (AD) compounds. For this purpose, tacrine and the benzylpiperidine moiety of donepezil were fused with a hydrazone group to achieve a small library of tacrine-donepezil hybrids. In agreement with the design, all compounds showed inhibitory activity toward both acetylcholinesterase (AChE) and butyrylcholinesterase (BChE) with IC50 values in the low micromolar range. Kinetic studies on the most potent cholinesterase (ChE) inhibitors within the series showed a mixed-type inhibition mechanism on both enzymes. Also, the docking studies indicated that the compounds inhibit ChEs by dual binding site (DBS) interactions. Notably, tacrine-donepezil hybrids also exhibited significant neuroprotection against H2O2-induced cell death in a differentiated human neuroblastoma (SH-SY5Y) cell line at concentrations close to their IC50 values on ChEs and showed high to medium blood-brain barrier (BBB) permeability on human cerebral microvascular endothelial cells (HBEC-5i). Besides, the compounds do not cause remarkable toxicity in a human hepatocellular carcinoma cell line (HepG2) and SH-SY5Y cells. Additionally, the compounds were predicted to also have good bioavailability. Among the tested compounds, H4, H16, H17, and H24 stand out with their biological profile. Taken together, the proposed novel tacrine-donepezil scaffold represents a promising starting point for the development of novel anti-ChE multifunctional agents against AD.

Systematic Investigation of Dual-Target-Directed Ligands

Multitarget-directed ligands (MTDLs) are compounds rationally designed to affect multiple targets, aiming for a better therapeutic profile. For over 20 years, MTDLs have garnered increasing attention, the idea being that their full potential would have been achieved, thanks to unprecedented target combinations and advanced medicinal chemistry strategies. This study presents a literature mining effort resulting in a data set of dual-target-directed ligands (DTDLs), the fundamental example of MTDLs. We used this data set to evaluate the rationale behind target selection and the chemical novelty of DTDLs targeting specific protein combinations. Our analysis focused on DTDL targets in terms of biological function, disease association, structure, and chemogenomic traits. We also compared DTDLs with single-target compounds. We found that well-known target pathology associations often guide DTDL design, leveraging existing chemical scaffolds and binding pocket similarities. These findings highlight the current state of the field and suggest substantial untapped potential for rational polypharmacology.

Current therapy in amyotrophic lateral sclerosis (ALS): A review on past and future therapeutic strategies

Amyotrophic lateral sclerosis (ALS) is a fatal neurodegenerative disease that affects the first and second motoneurons (MNs), associated with muscle weakness, paralysis and finally death. The exact etiology of the disease still remains unclear. Currently, efforts to develop novel ALS treatments which target specific pathomechanisms are being studied. The mechanisms of ALS pathogenesis involve multiple factors, such as protein aggregation, glutamate excitotoxicity, oxidative stress, mitochondrial dysfunction, apoptosis, inflammation etc. Unfortunately, to date, there are only two FDA-approved drugs for ALS, riluzole and edavarone, without curative treatment for ALS. Herein, we give an overview of the many pathways and review the recent discovery and preclinical characterization of neuroprotective compounds. Meanwhile, drug combination and other therapeutic approaches are also reviewed. In the last part, we analyze the reasons of clinical failure and propose perspective on the treatment of ALS in the future.

Design, synthesis, in vitro and in silico evaluations of new isatin-triazine- aniline hybrids as potent anti- Alzheimer multi-target directed lead compounds

Multi target directed ligands (MTDLs) are one of the promising tools for treatment of complex disease like Alzheimer's disease (AD). In this study, using rational design, we synthesized new 15 hybrids of the s-triazine, isatin and aniline derivatives as anti- AD compounds. The design was as way as that new compounds could had anti cholinesterase (ChE), antioxidant and biometal chelation ability. In vitro biological evaluation against ChE enzymes showed that these molecules were excellent inhibitors with IC50 values ranging from 0.2 nM to 734.5 nM for acetylcholinesterase (AChE), and 0.02 μM to 1.92 μM for butyrylcholinesterase (BChE). Among these compounds, 8 l with IC50 AChE = 0.7 nM, IC50 BChE = 0.09 μM and 8n with IC50 AChE = 0.2 nM, IC50 BChE = 0.03 μM were the most potent compounds. In silico studies showed that these molecules had key and effective interactions with the corresponding enzymes residues. The molecules with hydroxyl group on aniline moiety had also good antioxidant activity with EC50 values ranging from 64.2 μM to 103.6 μM. The UV-Vis spectroscopy study revealed that molecule 8n was also able to chelate biometals such as Zn2+, Cu2+and Fe2+ properly. It was concluded that these molecules could be excellent lead compounds for future studies.

Impact of GSK-3β and CK-1δ on Wnt signaling pathway in alzheimer disease: A dual target approach

Alzheimer's disease (AD) is an enigmatic neurological illness that offers few treatment options. Recent exploration has highlighted the crucial connection of the Wnt signaling pathway in AD pathogenesis, shedding light on potential therapeutic targets. The present study focuses on the dual targeting of glycogen synthase kinase-3β (GSK-3β) and casein kinase-1δ (CK-1δ) within the framework of the Wnt signaling pathway as a possible technique for AD intervention. GSK-3β and CK-1δ are multifunctional kinases known for their roles in tau hyperphosphorylation, amyloid processing, and synaptic dysfunction, all of which are major hallmarks of Alzheimer's disease. They are intricately linked to Wnt signaling, which plays a pivotal part in sustaining neuronal function and synaptic plasticity. Dysregulation of the Wnt pathway in AD contributes to cognitive decline and neurodegeneration. This review delves into the molecular mechanisms by which GSK-3β and CK-1δ impact the Wnt signaling pathway, elucidating their roles in AD pathogenesis. We discuss the potential of small-molecule inhibitors along with their SAR studies along with the multi-targetd approach targeting GSK-3β and CK-1δ to modulate Wnt signaling and mitigate AD-related pathology. In summary, the dual targeting of GSK-3β and CK-1δ within the framework of the Wnt signaling pathway presents an innovative and promising avenue for future AD therapies, offering new hope for patients and caregivers in the quest to combat this challenging condition.