In vitro and in vivo Investigations of 4-Substituted 2-Phenylquinazoline derivatives as multipotent ligands for the treatment of Alzheimer's disease

The pathology of Alzheimer's disease (AD) is complex due to its multifactorial nature and single targeting drugs proved inefficient. A series of novel 4-N-substituted-2-phenylquinazoline derivatives was designed and synthesized as potential multi-target directed ligands (MTDLs) through dual inhibition of AChE and MAO-B enzymes along with Aβ42 aggregation inhibition for the treatment of AD. Two compounds in the series, VAV-8 and VAV-19 were found to be the most potent inhibitors of both AChE and MAO-B enzymes and moderate inhibitor of Aβ42, with good thermodynamic stability at the binding pocket of the enzymes. Both the ligands showed moderate ROS inhibition and neuroprotection potential and found to be permeable to the blood-brain barrier. Furthermore, VAV-8 was subjected to toxicity evaluation and in vivo investigation using a zebrafish model. In adult zebrafish, VAV-8 (5 μM, and 10 μM) was found to be effective in reducing cognitive deterioration, neurodegeneration, and oxidative stress induced by scopolamine. Thus, these quinazoline derivatives have the potential to be developed as MTDLs for the treatment of Alzheimer's disease.

Multi-target-directed therapeutic strategies for Alzheimer's disease: controlling amyloid-β aggregation, metal ion homeostasis, and enzyme inhibition

Alzheimer's disease (AD) is the most prevalent neurodegenerative dementia, marked by progressive cognitive decline and memory impairment. Despite advances in therapeutic research, single-target-directed treatments often fall short in addressing the complex, multifactorial nature of AD. This arises from various pathological features, including amyloid-β (Aβ) aggregate deposition, metal ion dysregulation, oxidative stress, impaired neurotransmission, neuroinflammation, mitochondrial dysfunction, and neuronal cell death. This review illustrates their interrelationships, with a particular emphasis on the interplay among Aβ, metal ions, and AD-related enzymes, such as β-site amyloid precursor protein cleaving enzyme 1 (BACE1), matrix metalloproteinase 9 (MMP9), lysyl oxidase-like 2 (LOXL2), acetylcholinesterase (AChE), and monoamine oxidase B (MAOB). We further underscore the potential of therapeutic strategies that simultaneously inhibit Aβ aggregation and address other pathogenic mechanisms. These approaches offer a more comprehensive and effective method for combating AD, overcoming the limitations of conventional therapies.

Identification of potential JNK3 inhibitors through virtual screening, molecular docking and molecular dynamics simulation as therapeutics for Alzheimer's disease

Alzheimer's disease (AD) is a complex neurological disorder and no effective drug is available for its treatment. Numerous pathological conditions are believed to be responsible for the initiation and development of AD including c-Jun N-terminal kinases (JNKs). The JNKs are one of the enzymes from the mitogen-activated protein kinase (MAPK) family that controls the phosphorylation of various transcription factors on serine and threonine residues, and hold significant responsibilities in tasks like gene expression, cell proliferation, differentiation, and apoptosis. Since, JNK3 is primarily expressed in the brain hence its increased levels in the brain are associated with the AD pathology promoting neurofibrillary tangles, senile plaques, neuroinflammation, and nerve cell apoptosis. The current research work is focused on the development of novel JNK inhibitors as therapeutics for AD employing a structure-based virtual screening (SBVS) approach. The ZINC database (14634052 compounds) was investigated after employing pan assay interference (PAINs), drug-likeness, and diversity picking filter to distinguish molecules interacting with JNK3 by following three docking precision criteria: High Throughput Virtual Screening (HTVS), Standard Precision (SP), and Extra Precision (XP) & MMGBSA. Five lead molecules showed a better docking score in the range of -13.091 to -14.051 kcal/mol better than the reference compound (- 11.828 kcal/mol). The lead compounds displayed acceptable pharmacokinetic properties and were subjected to molecular dynamic simulations of 100 ns and binding free energy calculations. All the lead molecules showed stable RMSD and hydrogen bond interactions throughout the trajectory. The ∆GMM/PBSA_total score for the lead compounds ZINC220382956, ZINC147071339, ZINC207081127, ZINC205151456, ZINC1228819126, and CC-930 was calculated and found to be - 31.39, - 42.8, - 37.04, - 39.01, - 36.5, - 34.16 kcal/mol, respectively. Thus, it was concluded that the lead molecules identified in these studies have the potential to be explored as potent JNK3 inhibitors.

A decade of pyridine-containing heterocycles in US FDA approved drugs: a medicinal chemistry-based analysis

Heterocyclic scaffolds, particularly, pyridine-containing azaheterocycles, constitute a major part of the drugs approved in the past decade. In the present review, we explored the pyridine ring part of US FDA-approved small molecules (2014-2023). The analysis of the approved drugs bearing a pyridine ring revealed that a total of 54 drugs were approved. Among them, the significant number comprised the anticancer category (18 drugs, 33%), followed by drugs affecting the CNS system (11 drugs, 20%), which include drugs to treat migraines, Parkinsonism disorders, chemotherapeutic-induced nausea, insomnia, and ADHD or as CNS-acting analgesics or sedatives. Next, six drugs (11%) were also approved to treat rare conditions, followed by five drugs that affect the hematopoietic system. The analysis also revealed that drug approval was granted for antibiotics, antivirals, and antifungals, including drugs for the treatment of tropical and sub-tropical diseases. Primary drug targets explored were kinases, and the major metabolizing enzyme was CYP3A4. Further analysis of formulation types revealed that 50% of the approved drugs were tablets, followed by 17% capsules and 15% injections. Elemental analysis showed that most approved drugs contained sulfur, while fluorine was noted in 32 compounds. Therefore, the present review is a concerted effort to cover drugs bearing pyridine rings approved in the last decade and provide thorough discussion and commentary on their pharmacokinetics and pharmacodynamics aspects. Furthermore, in-depth structural and elemental analyses were explored, thus providing comprehensive guidance for medicinal chemists and scientists working in allied science domains.

Phenylstyrylpyrimidine derivatives as potential multipotent therapeutics for Alzheimer's disease

Alzheimer's disease (AD) is a multifactorial neurological disorder that affects millions of people worldwide. Despite extensive research efforts, there are currently no effective disease-modifying therapeutics available for the complete cure of AD. In the current study, we have designed and synthesized a series of phenyl-styryl-pyrimidine derivatives as potential multifunctional agents against different targets of AD. The compounds were evaluated for their ability to inhibit acetylcholinesterase (AChE), monoamine oxidase (MAO) and β amyloid aggregation which are associated with the initiation and progression of the disease. Several compounds in the series exhibited potent inhibitory activity against AChE and MAO-B, with IC50 values in the low micromolar range. In particular, two compounds, BV-12 and BV-14, were found to exhibit a multipotent profile and showed non-competitive inhibition against MAO-B with IC50 values of 4.93 ± 0.38 & 7.265 ± 0.82 μM, respectively and AChE inhibition with IC50 values of 7.265 and 9.291 μM, respectively. BV-12 and BV-14 also displayed β amyloid self-aggregation inhibition of 32.98% and 23.25%, respectively. Furthermore, molecular modelling studies revealed that BV-14 displayed a docking score of -11.20 kcal mol-1 with MAO-B & -6.767 kcal mol-1 with AChE, forming a stable complex with both proteins. It was concluded that phenyl-styryl-pyrimidine derivatives have the potential to be developed as multitarget directed ligands for the treatment of AD.

Exploration of oxadiazole clubbed benzhydrylpiperazine pharmacophoric features as structural feature for antidepressant activity: In vitro, in vivo and in silico analysis

Arylpiperazine clubbed various heterocyclic molecules present potential pharmacophoric structural features for the development of psychoactive drugs. There are various CNS active molecules possessing arylpiperazine moiety in their pharmacophore approved by USFDA. In the current study, we have explored the benzhydrylpiperazine moiety clubbed with various substituted oxadiazole moieties (AP1-12) for their monoamine oxidase (MAO) inhibition and antidepressant potential. Compounds AP3 and AP12 exhibited highly potent and selective MAO-A inhibition with IC50 values of 1.34 ± 0.93 µM and 1.13 ± 0.54 µM, respectively, and a selectivity index of 10- and 13-folds, respectively. Both the compounds displayed reversible binding character at the active site of MAO-A. In further in vivo evaluation, both the compounds AP3 and AP12 displayed potential antidepressant-like character in FST and TST studies via significantly reduced immobility time in comparison to non-treated animals. These compounds displayed no cytotoxicity in SH-SY5Y cell lines, which indicates that these compounds are safe for further evaluation. In silico studies reveal that synthesized compounds possess drug-likeness with minimal to no toxicity. In silico studies were conducted to understand the binding interactions and stability of compounds at the binding pocket of enzyme and observed that both the best compounds fit well at the active site of MAO-A lined by amino acid residues Tyr69, Asn181, Phe208, Ile335, Leu337, Phe352, and Tyr444 similar to standard MAO-A inhibitor clorgiline. The molecular dynamic studies demonstrated that AP3 and AP12 formed quite a stable complex at the active site of MAO-A and did not break under small abruption forces. The favourable binding interactions and appropriate ADMET properties present the benzhydrylpiperazine clubbed oxadiazole pharmacophoric features as a potential structural skeleton for further clinical evaluation and development of a new antidepressant drug molecule.

Calcium channel blockers' contribution to overcoming Current drug discovery challenges in Alzheimer's disease

INTRODUCTION

Alzheimer's disease (AD) is a progressive, irreversible, and multifactorial brain disorder that gradually and insidiously destroys individual's memory, thinking, and other cognitive abilities.

AREAS COVERED

In this perspective, the authors examine the complex and multifactorial nature of Alzheimer's disease and believe that the best approach to develop new drugs is the MTDL strategy, which obviously faces several challenges. These challenges include identifying the key combination of targets and their suitability for coordinated actions, as well as developing an acceptable pharmacokinetic and toxicological profile to deliver a drug candidate.

EXPERT OPINION

Since calcium plays a crucial role in the pathology of AD, a polypharmacological approach with calcium channel blockers reinforced by activities targeting other factors involved in AD is a serious option in our opinion. This is exemplified by a phase III clinical trial using a drug combination approach with Losartan, Amlodipine (a calcium channel blocker), and Atorvastatin, as well as several MTDL-based calcium channel blockade approaches with a promising in vitro and in vivo profile.

Multicomponent reactions as a privileged tool for multitarget-directed ligand strategies in Alzheimer's disease therapy

Among neurodegenerative pathologies affecting the older population, Alzheimer's disease is the most common type of dementia and leads to neurocognitive and behavioral disorders. It is a complex and progressive age-related multifactorial disease characterized by a series of highly interconnected pathophysiological processes. Within the last decade, the multitarget-directed ligand strategy has emerged as a viable approach to developing complex molecules that exhibit several pharmacophores which can target the different enzymes and receptors involved in the pathogenesis of the disease. Herein, we focus on using multicomponent reactions such as Hantzsch, Biginelli and Ugi to develop these biologically active multitopic ligands.

Design, Synthesis, and Pharmacological Evaluation of N-Propargylated Diphenylpyrimidines as Multitarget Directed Ligands for the Treatment of Alzheimer's Disease

Alzheimer's disease (AD), a multifactorial complex neural disorder, is categorized with progressive memory loss and cognitive impairment as main clinical features. The multitarget directed ligand (MTDL) strategy is explored for the treatment of multifactorial diseases such as cancer and AD. Herein, we report the synthesis and screening of 24 N-propargyl-substituted diphenylpyrimidine derivatives as MTDLs against acetylcholine/butyrylcholine esterases and monoamine oxidase enzymes. In this series, VP1 showed the most potent MAO-B inhibitory activity with an IC₅₀ value of 0.04 ± 0.002 μM. VP15 with an IC₅₀ value of 0.04 ± 0.003 μM and a selectivity index of 626 (over BuChE) displayed the most potent AChE inhibitory activity in this series. In the reactive oxygen species (ROS) inhibition studies, VP1 reduced intercellular ROS levels in SH-SY5Y cells by 36%. This series of compounds also exhibited potent neuroprotective potential against 6-hydroxydopamine-induced neuronal damage in SH-SY5Y cells with up to 90% recovery. In the in vivo studies in the rats, the hydrochloride salt of VP15 was orally administered and found to cross the blood-brain barrier and reach the target site. VP15·HCl significantly attenuated the spatial memory impairment and improved the cognitive deficits in the mice. This series of compounds were found to be irreversible inhibitors and showed no cytotoxicity against neuronal cells. In in silico studies, the compounds attained thermodynamically stable orientation with complete occupancy at the active site of the receptors. Thus, N-propargyl-substituted diphenylpyrimidines displayed drug-like characteristics and have the potential to be developed as MTDLs for the effective treatment of AD.

A Review on the Arylpiperazine Derivatives as Potential Therapeutics for the Treatment of Various Neurological Disorders

Abstract:

Neurological disorders are disease conditions related to the neurons and central nervous system (CNS). Any kind of structural, electrical, biochemical and functional abnormalities in neurons can lead to various types of disorders like Alzheimer’s disease (AD), depression, Parkinson’s disease (PD), epilepsy, stroke, etc. Currently available medicines are symptomatic and do not treat the disease state. Thus, novel CNS active agents with the potential of complete treatment of an illness are highly desired. A range of small organic molecules are being explored as potential drug candidates for the cure of different neurological disorders. In this context, arylpiperazine has been found to be a versatile scaffold and indispensable pharmacophore in many CNS active agents. A number of molecules with arylpiperazine nucleus have been developed as potent leads for the treatment of AD, PD, depression and other disorders. The arylpiperazine nucleus can be optionally substituted at different chemical structures and offer flexibility for the synthesis of large number of derivatives. In the current review article, we have explored the role of various arylpiperazine containing scaffolds against different neurological disorders, including AD, PD, and depression. The structure-activity relationship studies were conducted for recognizing potent lead compounds. This review article may provide important clues on the structural requirements for the design and synthesis of effective molecules as curative agents for different neurological disorders.

Multi-Target-Directed Ligands as an Effective Strategy for the Treatment of Alzheimer's Disease

Alzheimer's disease (AD) is a complex neurological disorder, and multiple pathological factors are believed to be involved in the genesis and progression of the disease. A number of hypotheses, including Acetylcholinesterase, Monoamine oxidase, β-Amyloid, Tau protein, etc., have been proposed for the initiation and progression of the disease. At present, acetylcholine esterase inhibitors and memantine (NMDAR antagonist) are the only approved therapies for the symptomatic management of AD. Most of these single-target drugs have miserably failed in the treatment or halting the progression of the disease. Multi-factorial diseases like AD require complex treatment strategies that involve simultaneous modulation of a network of interacting targets. Since the last few years, Multi-Target-Directed Ligands (MTDLs) strategy, drugs that can simultaneously hit multiple targets, is being explored as an effective therapeutic approach for the treatment of AD. In the current review article, the authors have briefly described various pathogenic pathways associated with AD. The importance of Multi-Target-Directed Ligands and their design strategies in recently reported articles have been discussed in detail. Potent leads are identified through various structure-activity relationship studies, and their drug-like characteristics are described. Recently developed promising compounds have been summarized in the article. Some of these MTDLs with balanced activity profiles against different targets have the potential to be developed as drug candidates for the treatment of AD.

Anti-proliferative potential of triphenyl substituted pyrimidines against MDA-MB-231, HCT-116 and HT-29 cancer cell lines

A series of triphenyl substituted pyrimidines as analogous of colchicine and combretastatin A-4 was synthesized and evaluated for the antiproliferative potential. The compounds were screened against MDA-MB-231, HCT-116 and HT-29 cell lines using MTT assay. Most of the compounds displayed antiproliferative activity in low to sub micro molar concentration. Amongst the synthesized derivatives, compounds HK-2, HK-10 and HK-13 were found to be effective against all the three cancer cell lines. HK-2 exhibited IC₅₀ values of 3.39 µM, 4.78 µM and 4.23 µM, HK-10 showed IC₅₀ values of 0.81 µM, 5.89 µM, 4.96 µM and HK-13 showed IC₅₀ values 3.24 µM, 4.93 µM and 4.73 µM against MDA-MB-231, HCT-116 and HT-29 cancer cell lines, respectively. HK-10 was found to be the most potent compound in the series with IC₅₀ values of 0.81 µM against MDA-MB-231. In the cell cycle analysis, HK-2 and HK-10 showed cell arrest at G2/M phase of the cell cycle while HK-13 inhibited cell growth at the G1/G0 phase. All the three compounds showed cell death induced through apoptosis. In the docking studies, HK-2, HK-10 and HK-13 were found to fit well in the colchicine binding site of the tubulin. Some of the compounds in the current series were found to be promising against all the three cancer cell lines and may act as potent leads for further development.

Synthesis, Molecular Docking and α-Glucosidase Inhibitory Activity Study of 2,4,6-triaryl Pyrimidine Derivatives

Background:

α-Glucosidase inhibitors hinder the carbohydrate digestion and play an important role in the treatment of diabetes mellitus. α-glucosidase inhibitors available on the market are acarbose, miglitol, and voglibose. However, the use of acarbose is diminishing due to related side effects like diarrhea, bloating and abdominal distension.

Objectives:

This study aimed to synthesize 2,4,6-triaryl pyrimidines derivatives, screen their α- glucosidase inhibitory activity, perform kinetic and molecular docking studies.

Methods:

A series of 2,4,6-triaryl pyrimidine derivatives were synthesized and their α-glucosidase inhibitory activity was screened in vitro. Pyrimidine derivatives 4a-m were synthesized via a twostep reaction with a yield between 49 and 93%. The structure of the synthesized compounds was confirmed by different spectroscopic techniques (IR, NMR and MS). The in vitro α-glucosidase inhibition activities of the synthesized compounds 4a-m was also evaluated against Saccharomyces cerevisiae α-glucosidase.

Results and Discussion:

The majority of synthesized compounds had α-glucosidase inhibitory activity. Particularly compounds 4b and 4g were the most active compounds with an IC50 value of 125.2± 7.2 and 139.8 ± 8.1 μM respectively. The kinetic study performed for the most active compound 4b revealed that the compound was a competitive inhibitor of Saccharomyces cerevisiae α-glucosidase with Ki of 122 μM. The molecular docking study also revealed that the two compounds have important binding interactions with the enzyme active site.

Conclusion:

2,4,6-triarylpyrimidine derivative 4a-m were synthesized and screened for α- glucosidase inhibitory activity. Most of the synthesized compounds possess α-glucosidase inhibitory activity, and compound 4b demonstrated the most significant inhibitory action as compared to acarbose.

Self-Inclusion and Dissociation of a Bridging β-Cyclodextrin Triplet

To understand the self-inclusion and the dissociation in a branched β-cyclodextrin (CD) system, we designed and synthesized a β-CD trimer in which each CD group is connected to one of bridging arms of a planar triphenylbenzene core through a CuAAC click reaction. Only one rather than two or all of the three host CDs was demonstrated to be in a self-including state in water, while no self-inclusion was observed to occur in dimethylsulfoxide (DMSO) via the characterization of ¹H and NOESY NMR spectra. The configuration structures of the CD groups in the self-included state were evaluated, and the dissociation to free state in water was investigated under various conditions like heating, increased acidity, and discharging versus the addition of competitive guests. While raised temperature and increased acidity did not break the self-inclusion, two adamantane guest molecules were found to show capability in driving the equilibrium to get back to free state against the self-inclusion. The inclusion process of the added guests was believed to involve in the dissociation of the self-inclusion and the occupation of the guests in CD cavity. The results of host-guest interaction study indicated that the stable combination of guests was favorable for blocking the structural overturning of glucose toward trapping the bridging group into the cavity.

Design, Synthesis and Biological Evaluation of New Antioxidant and Neuroprotective Multitarget Directed Ligands Able to Block Calcium Channels

We report herein the design, synthesis and biological evaluation of new antioxidant and neuroprotective multitarget directed ligands (MTDLs) able to block Ca²⁺ channels. New dialkyl 2,6-dimethyl-4-(4-(prop-2-yn-1-yloxy)phenyl)-1,4-dihydropyridine-3,5-dicarboxylate MTDLs 3a–t, resulting from the juxtaposition of nimodipine, a Ca²⁺ channel antagonist, and rasagiline, a known MAO inhibitor, have been obtained from appropriate and commercially available precursors using a Hantzsch reaction. Pertinent biological analysis has prompted us to identify the MTDL 3,5-dimethyl-2,6–dimethyl–4-[4-(prop–2–yn–1-yloxy)phenyl]-1,4-dihydro- pyridine- 3,5-dicarboxylate (3a), as an attractive antioxidant (1.75 TE), Ca²⁺ channel antagonist (46.95% at 10 μM), showing significant neuroprotection (38%) against H₂O₂ at 10 μM, being considered thus a hit-compound for further investigation in our search for anti-Alzheimer’s disease agents.

Chromenones as Multineurotargeting Inhibitors of Human Enzymes

The complex nature of multifactorial diseases, such as Morbus Alzheimer, has produced a strong need to design multitarget-directed ligands to address the involved complementary pathways. We performed a purposive structural modification of a tetratarget small-molecule, that is contilisant, and generated a combinatorial library of 28 substituted chromen-4-ones. The compounds comprise a basic moiety which is linker-connected to the 6-position of the heterocyclic chromenone core. The syntheses were accomplished by Mitsunobu- or Williamson-type ether formations. The resulting library members were evaluated at a panel of seven human enzymes, all of which being involved in the pathophysiology of neurodegeneration. A concomitant inhibition of human acetylcholinesterase and human monoamine oxidase B, with IC₅₀ values of 5.58 and 7.20 μM, respectively, was achieved with the dual-target 6-(4-(piperidin-1-yl)butoxy)-4H-chromen-4-one (7).

Synthesis and anticonvulsant activity of 6-methyl-2-((2-oxo-2-arylethyl)thio)pyrimidin-4(3 H)-one derivatives and products of their cyclization

The alkylation of 6-methyl-2-thioxo-2,3-dihydro-1H-pyrimidine-4-one phenacyl bromides under different conditions was investigated. It was found that during the reaction in the medium of DMF/K2CO3 a mixture of 2-(2-aryl-2-oxoethyl)thio-6-methyl-pyrimidine-4(3H)-one and 3-hydroxy-3-aryl-7-methyl-2,3-dihydro-5H-thiazolo[3,2-a]pyrimidine-5-one was formed. The holding of the resulting mixture in the concentrated sulphuric acid leads to the formation of cyclization products - derivatives of 3-aryl-7-methyl-5H-thiazolo[3,2-a]pyrimidin-5-one with high yields. Individual S-alkylated derivatives – 2-(2-aryl-2-oxoethyl)thio-6-methyl-pyrimidine-4(3H)-one - were obtained by reacting in methanol in the presence of sodium methoxide. Pharmacological screening of synthesized compounds for anticonvulsant activity on the model of pentylenetetrazole seizures in rats was carried out and some regularity “structure-activity” was established.

Novel approaches to the discovery of selective human monoamine oxidase-B inhibitors: is there room for improvement?

Introduction: Selective monoamine oxidase-B (MAO-B) inhibitors are currently used as coadjuvants for the treatment of early motor symptoms in Parkinson's disease. They can, based on their chemical structure and mechanism of inhibition, be categorized into reversible and irreversible agents. Areas covered: This review provides a comprehensive update on the development state of selective MAO-B inhibitors describing the results, structures, structure-activity relationships (SARs) and Medicinal chemistry strategies as well as the related shortcomings over the past five years. Expert opinion: Researchers have explored and implemented new and old chemical scaffolds achieving high inhibitory potencies and isoform selectivity. Most of them were characterized and proposed as multitarget agents able to act at different levels (including AChE inhibition, H3R or A_2AR antagonism, antioxidant and chelating properties, Aβ_1-42 aggregation reduction) in the network of aetiologies of neurodegenerative disorders. These results can also be used to avoid 'cheese-reaction' effects and the occurrence of serotonergic syndrome in patients.

4,6-Diphenylpyrimidine Derivatives as Dual Inhibitors of Monoamine Oxidase and Acetylcholinesterase for the Treatment of Alzheimer's Disease

Alzheimer's disease (AD) is a neurodegenerative disorder with multifactorial pathogenesis. Monoamine oxidase (MAO) and acetylcholinesterase enzymes (AChE) are potential targets for the treatment of AD. A total of 15 new propargyl containing 4,6-diphenylpyrimidine derivatives were synthesized and screened for the MAO and AChE inhibition activities along with ROS production inhibition and metal-chelation potential. All the synthesized compounds were found to be selective and potent inhibitors of MAO-A and AChE enzymes at nanomolar concentrations. VB1 was found to be the most potent MAO-A and BuChE inhibitor with IC₅₀ values of 18.34 ± 0.38 nM and 0.666 ± 0.03 μM, respectively. It also showed potent AChE inhibition with an IC₅₀ value of 30.46 ± 0.23 nM. Compound VB8 was found to be the most potent AChE inhibitor with an IC₅₀ value of 9.54 ± 0.07 nM and displayed an IC₅₀ value of 1010 ± 70.42 nM against the MAO-A isoform. In the cytotoxic studies, these compounds were found to be nontoxic to the human neuroblastoma SH-SY5Y cells even at 25 μM concentration. All the compounds were found to be reversible inhibitors of MAO-A and AChE enzymes. In addition, these compounds also showed good neuroprotective properties against 6-OHDA- and H₂O₂-induced neurotoxicity in SH-SY5Y cells. All the compounds accommodate nicely to the hydrophobic cavity of MAO-A and AChE enzymes. In the molecular dynamics simulation studies, both VB1 and VB8 were found to be stable in the respective cavities for 30 ns. Thus, 4,6-diphenylpyrimidine derivatives can act as promising leads in the development of dual-acting inhibitors targeting MAO-A and AChE enzymes for the treatment of Alzheimer's disease.