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Background: Alzheimer's disease (AD) is a neurodegenerative disease characterized by beta-amyloid (Aβ) deposition and increased acetylcholinesterase (AchE) enzyme activities. Indole 3 carbinol (I3C) and diindolylmethane (DIM) are reported to have neuroprotective activities against various neurological diseases, including ischemic stroke, Parkinson's disease, neonatal asphyxia, depression, stress, neuroinflammation, and excitotoxicity, except for AD. In the present study, we have investigated the anti-AD effects of I3C and DIM. Methods: Docking and molecular dynamic studies against AchE enzyme and network pharmacological studies were conducted for I3C and DIM. I3C and DIM's neuroprotective effects against self and AchE-induced Aβ aggregation were investigated. The neuroprotective effects of I3C and DIM against Aβ-induced neurotoxicity were assessed in SH-S5Y5 cells by observing cell viability and ROS. Results: Docking studies against AchE enzyme with I3C and DIM show binding efficiency of −7.0 and −10.3, respectively, and molecular dynamics studies revealed a better interaction and stability between I3C and AchE and DIM and AchE. Network pharmacological studies indicated that I3C and DIM interacted with several proteins involved in the pathophysiology of AD. Further, I3C and DIM significantly inhibited the AchE (IC50: I3C (18.98 µM) and DIM (11.84 µM)) and self-induced Aβ aggregation. Both compounds enhanced the viability of SH-S5Y5 cells that are exposed to Aβ and reduced ROS. Further, I3C and DIM show equipotential neuroprotection when compared to donepezil. Conclusions: Our findings indicate that both I3C and DIM show anti-AD effects by inhibiting the Aβ induced neurotoxicity and AchE activities. [ABSTRACT FROM AUTHOR]

Alzheimer's disease (AD) is a complex, degenerative condition linked to memory loss and cognitive degradation. The phenyl sulfonyl‐pyrimidine derivatives containing dimethoxy‐chloro substituent (BS‐10 and BS‐22) were previously recognized as multitarget‐directed ligands (MTDLs) due to their ability to inhibit acetylcholinesterase (AChE) at low nanomolar concentrations (IC50=47.33±0.02 and 51.36±0.04 nM respectively) while also reducing amyloid beta (Aβ) aggregation. In the current investigation, we investigated the in vivo and ex‐vivo effects of BS‐10 and BS‐22 chemicals on cognition and the cholinergic system. We have used scopolamine and Aβ1‐42 models of cognitive impairment which were measured during Y‐maze and passive avoidance apparatus. Results showed that BS‐10 at 10 mg/kg compared to BS‐22 at 20 mg/kg rescued memory impairment more significantly. Moreover, ex‐vivo and biochemical studies exhibited both compounds improved the hippocampal acetylcholine (Ach) level by reducing AChE activity as well as antioxidant properties. In addition, BS‐10 and BS‐22 attenuated Aβ1‐42 induced cognitive deficiency in rats during Y‐maze tests and significantly restored mitochondrial membrane potential and reduced the tau protein level in rats (p<0.05). In summary, our results indicated that MTDLs BS‐10 and BS‐22 would be a promising therapeutic approach in AD. [ABSTRACT FROM AUTHOR]

Vasicine is a pyrroloquinazoline alkaloid, which has been isolated from the plant Adhatoda vasica. Naturally inspired semi-synthetic transformations were prepared using vasicine as a synthetic precursor to overcome Alzheimer's disease (AD). These semi-synthetic analogs exhibited stable interactions and were well resided at AChE and BChE active sites in in-silico studies. Further, in-vitro experiments were performed to assess the cholinesterase inhibitory activity and reduction of amyloid-beta (Aβ 1-42) plaques potency, PAMPA assay permeability, and antioxidant activity, these findings suggested that compound VA10 can be a lead molecule among all the synthesized analogs. The compound VA10 binds towards AChE peripheral anionic site (PAS) property was established through propidium iodide displacement assay. Moreover, VA10 showed no notable cytotoxicity and exhibited neuroprotective nature on Aβ 1-42 treated SH-SY5Y cell line. In addition, VA10 was found to be safe in rats, which was confirmed by acute oral toxicity studies. Furthermore, i n-vivo studies suggested that compound VA10 (10 mg/kg, p.o) ameliorated the memory and cognition impairment in scopolamine-induced amnesia model and Aβ 1-42 induced Alzheimer rat model. Ex-vivo studies of compound VA10 demonstrate improved ACh levels by inhibiting AChE activity in rat brain. Moreover, histopathological observations on rats brain sections indicate VA10 (10 mg/kg, p.o) recovered the neuronal cells at hippocampus region (DG, CA3, and CA1). These positive experimental data from in-silico , in-vitro and in-vivo studies, suggested that compound VA10 can be a lead compound for further preclinical development studies as a naturally derived alkaloid for anti-AD. [Display omitted] • Discovery of multi-target directed ligands from alkaloid vasicine through semi synthesis. • Compounds VA01-VA25, well resided at AChE and BChE active site in in-silico studies. • In in-vitro experiments, VA10 effectively inhibited the AChE, BChE, and Aβ 1-42. • VA10 ameliorated the memory and cognitive dysfunctions by inhibiting AChE activity. • In hippocampus region, cell density was recovered in VA10 10 mg/kg treatment group. [ABSTRACT FROM AUTHOR]

Amyloid fibrils and hyperphosphorylated tau tangles are widely acceptable histological and biochemical pathogenic markers in Alzheimer's Disease (AD). Detecting these markers at an early stage could be beneficial for differentiating AD from other neuronal anomalies. Herein, a series of rhodanine (acceptor) based dyes in conjugation with a coumarin or carbostyril (donor) were synthesized and tested their ability to detect these biomarkers. The lead probe 19 displayed staining affinity for Aβ fibrils and tau tangles with little or no interaction with abundant plasma protein (BSA). Minimal cytotoxicity, brain accessibility, biocompatibility, and fluorescence sustainability across physiological pHs rendering it suitable for in-vivo imaging. Dual staining of histological samples validated affinity of probe 19 for Aβ plaques and tau tangles in AD brain tissue specimens via immunofluorescence, ThT (aggregated Aβ specific dye), and Tau-1 (tau filament-specific dye). Moreover, live in-vivo fluorescence imaging in mice and ocular labeling of Aβ in AD Drosophila models extend the preclinical applicability of probe 19 for screening purposes. On behalf of the following data, we assume that probe 19 can successfully detect pathological AD biomarkers in investigational studies. [Display omitted] • Newly developed Probe 19 detects Aβ plaques and tau tangles with low off-target signaling in brain tissue. • Tested successfully in mice and AD Drosophila flies, expanding its preclinical uses. • The studies unveiled the potential of probe as a reliable screening tool in AD investigational studies. [ABSTRACT FROM AUTHOR]

The complexity and multifaceted nature of Alzheimer's disease (AD) have driven us to further explore quinazoline scaffolds as multi-targeting agents for AD treatment. The lead optimization strategy was utilized in designing of new series of derivatives (AK-1 to AK-14) followed by synthesis, characterization, and pharmacological evaluation against human cholinesterase's (hChE) and β-secretase (hBACE-1) enzymes. Amongst them, compounds AK-1, AK-2, and AK-3 showed good and significant inhibitory activity against both hAChE and hBACE-1 enzymes with favorable permeation across the blood-brain barrier. The most active compound AK-2 revealed significant propidium iodide (PI) displacement from the AChE-PAS region and was non-neurotoxic against SH-SY5Y cell lines. The lead molecule (AK-2) also showed Aβ aggregation inhibition in a self- and AChE-induced Aβ aggregation, Thioflavin-T assay. Further, compound AK-2 significantly ameliorated Aβ-induced cognitive deficits in the Aβ-induced Morris water maze rat model and demonstrated a significant rescue in eye phenotype in the Aꞵ-phenotypic drosophila model of AD. Ex-vivo immunohistochemistry (IHC) analysis on hippocampal rat brains showed reduced Aβ and BACE-1 protein levels. Compound AK-2 suggested good oral absorption via pharmacokinetic studies and displayed a good and stable ligand-protein interaction in in-silico molecular modeling analysis. Thus, the compound AK-2 can be regarded as a lead molecule and should be investigated further for the treatment of AD. [Display omitted] • Novel quinazoline derivatives (AK-1 to AK-14) were designed via lead optimization and synthesized. • The designed derivatives were tested in-vitro for their hChE, hBACE-1, and hAβ inhibitory activity. • Compound AK-2 demonstrated good BBB permeability with non-neurotoxicity properties in differentiated SHSY-5Y cell lines. • Compound AK-2 showed good in-vivo activities in rats and Drosophila models. • Compound AK-2 revealed decreased level of Aβ and BACE-1 in ex-vivo IHC studies with good oral bioavailability via pk studies. [ABSTRACT FROM AUTHOR]

Inspite of established symptomatic relief drug targets, a multi targeting approach is highly in demand to cure Alzheimer's disease (AD). Simultaneous inhibition of cholinesterase (ChE), β secretase-1 (BACE-1) and Dyrk1A could be promising in complete cure of AD. A series of 18 diaryl triazine based molecular hybrids were successfully designed, synthesized, and tested for their hChE, hBACE-1, Dyrk1A and Aβ aggregation inhibitory potentials. Compounds S-11 and S-12 were the representative molecules amongst the series with multi-targeted inhibitory effects. Compound S-12 showed hAChE inhibition (IC 50 value = 0.486 ± 0.047 μM), BACE-1 inhibition (IC 50 value = 0.542 ± 0.099 μM) along with good anti -Aβ aggregation effects in thioflavin-T assay. Only compound S-02 of the series has shown Dyrk1A inhibition (IC 50 value = 2.000 ± 0.360 μM). Compound S-12 has also demonstrated no neurotoxic liabilities against SH-SY5Y as compared to donepezil. The in vivo behavioral studies of the compound S-12 in the scopolamine- and Aβ-induced animal models also demonstrated attanuation of learning and memory functions in rats models having AD-like characteristics. The ex vivo studies, on the rat hippocampal brain demonstrated reduction in certain biochemical markers of the AD brain with a significant increase in ACh level. The Western blot and Immunohistochemistry further revealed lower tau, APP and BACE-1 molecular levels. The drosophilla AD model also revealed improved eyephenotype after treatment with compound S-12. The molecular docking studies of the compounds suggested that compound S-12 was interacting with the ChE-PAS & CAS residues and catalytic dyad residues of the BACE-1 enzymes. The 100 ns molecular dynamics simulation studies of the ligand-protein complexed with hAChE and hBACE-1 also suggested stable ligand–protein confirmation throughout the simulation run. [Display omitted] • A series of 18 compounds (S 01-18) was designed based on the molecular hybridization and in silico approaches. • Compounds S-11 and S-12 have shown good BBB permeation and in vitro multi-targeted inhibitory efficacy. • Compound S-12 demonstrated attenuation of learning and memory functions in in vivo rat and Drosophila models. • Compound S-12 revealed lower tau, APP and BACE-1 molecular expressions in molecular mechanistic ex vivo studies. • Compound S-12 showed good oral bioavailability via pharmacokinetic studies. [ABSTRACT FROM AUTHOR]

[Display omitted] • Multi-targetable chalcones bearing n -aryl piperazine moiety were designed synthesized, and evaluated for the treatment of AD. • Compound 41 identified as potential ligand and may be considered as promising "lead". • It ameliorated cognitive dysfunctions and signified memory improvement in the in-vivo behavioural studies. • Ex vivo biochemical analysis showed reduced AChE and increased ACh levels along with antioxidant potential. The multi-target directed ligand (MTDL) discovery has been gaining immense attention in the development of therapeutics for Alzheimer's disease (AD). The strategy has been evolved as an auspicious approach suitable to combat the heterogeneity and the multifactorial nature of AD. Therefore, multi-targetable chalcone derivatives bearing N -aryl piperazine moiety were designed, synthesized, and evaluated for the treatment of AD. All the synthesized compounds were screened for the in vitro activity against acetylcholinesterase (AChE), butylcholinesterase (BuChE), β-secretase-1 (BACE-1), and inhibition of amyloid β (Aβ) aggregation. Amongst all the tested derivatives, compound 41 bearing unsubstituted benzylpiperazine fragment and para -bromo substitution at the chalcone scaffold exhibited balanced inhibitory profile against the selected targets. Compound 41 elicited favourable permeation across the blood–brain barrier in the PAMPA assay. The molecular docking and dynamics simulation studies revealed the binding mode analysis and protein–ligand stability of the compound with AChE and BACE-1. Furthermore, it ameliorated cognitive dysfunctions and signified memory improvement in the in-vivo behavioural studies (scopolamine-induced amnesia model). The ex vivo biochemical analysis of mice brain homogenates established the reduced AChE and increased ACh levels. The antioxidant activity of compound 41 was accessed with the determination of catalase (CAT) and malondialdehyde (MDA) levels. The findings suggested that compound 41 , containing a privileged chalcone scaffold, can act as a lead molecule for developing AD therapeutics. [ABSTRACT FROM AUTHOR]

Alzheimer's disease (AD) is a progressive brain disorder associated with slow loss of brain functions leading to memory failure and modest changes in behavior. The multifactorial neuropathological condition is due to a depletion of cholinergic neurons and accumulation of amyloid-beta (Aβ) plaques. Recently, a multi-target-directed ligand (MTDL) strategy has emerged as a robust drug discovery tool to overcome current challenges. In this research work, we aimed to design and develop a library of triazole-bridged aryl adamantane analogs for the treatment of AD. All synthesized analogs were characterized and evaluated through various in vitro and in vivo biological studies. The optimal compounds 32 and 33 exhibited potent inhibitory activities against acetylcholinesterase (AChE) (32 - IC 50 = 0.086 μM; 33 - 0.135 μM), and significant Aβ aggregation inhibition (20 μM). N-methyl- d -aspartate (NMDA) receptor (GluN1-1b/GluN2B subunit combination) antagonistic activity of compounds 32 and 33 measured upon heterologous expression in Xenopus laevis oocytes showed IC 50 values of 3.00 μM and 2.86 μM, respectively. The compounds possessed good blood-brain barrier permeability in the PAMPA assay and were safe for SH-SY5Y neuroblastoma (10 μM) and HEK-293 cell lines (30 μM). Furthermore, in vivo behavioral studies in rats demonstrated that both compounds improved cognitive and spatial memory impairment at a dose of 10 mg/kg oral administration. Together, our findings suggest triazole-bridged aryl adamantane as a promising new scaffold for the development of anti-Alzheimer's drugs. [Display omitted] • Development of new disease-modifying agents by multi-target-directed ligands with modern drug discovery approaches. • Novel triazole-bridged aryl adamantane analogs and biological evaluation of synthesized derivatives are reported. • Compounds 32 and 33 exhibited inhibition of AChE, BuChE and Aβ 1-42 aggregation. • In vivo behavioral studies demonstrated that compounds 32 and 33 improved cognitive and spatial memory impairment. • Compound 32 represents triazole-bridged aryl adamantane as a promising scaffold for the AD drug development. [ABSTRACT FROM AUTHOR]

Abstract The multitarget-directed strategy offers an effective and promising paradigm to treat the complex neurodegenerative disorder, such as Alzheimer's disease (AD). Herein, a series of N -benzylpiperidine analogs (17 – 31 and 32 – 46) were designed and synthesized as multi-functional inhibitors of acetylcholinesterase (AChE) and β-secretase-1 (BACE-1) with moderate to excellent inhibitory activities. Among the tested inhibitors, 25, 26, 40, and 41 presented the most significant and balanced inhibition against both the targets. Compounds 40 and 41 exhibited high brain permeability in the PAMPA-BBB assay, significant displacement of propidium iodide from the peripheral anionic site (PAS) of AChE, and were devoid of neurotoxicity towards SH-SY5Y neuroblastoma cell lines up to the maximum tested concentration of 80 μM. Meanwhile, both these compounds inhibited self- and AChE-induced Aβ aggregation in thioflavin T assay, which was also re-affirmed by morphological characterization of Aβ aggregates using atomic force microscopy (AFM). Moreover, 40 and 41 ameliorated the scopolamine-induced cognitive impairment in elevated plus and Y-maze experiments. Ex vivo and biochemical analysis established the brain AChE inhibitory potential and antioxidant properties of these compounds. Further, improvement in Aβ 1-42 -induced cognitive impairment was also observed by compound 41 in the Morris water maze experiment with significant oral absorption characteristics ascertained by the pharmacokinetic studies. Graphical abstract Image 1 Highlights • Design and synthesis of a series of N -benzylpiperidine analogs (17 – 46). • Compounds 25, 26, 40, and 41 exhibited balanced inhibition of AChE and BACE-1. • Propidium iodide displacement and inhibition of Aβ aggregation by 40 and 41. • Biochemical analysis of rat brain homogenates suggested antioxidant potential. • Amelioration of scopolamine- and Aβ-induced cognitive impairment in AD rat models. [ABSTRACT FROM AUTHOR]

Novel multifunctional 3,6-Diphenyl-1,4-bis(phenylsulfonyl)piperazine-2,5-dione derivatives were designed and synthesized for the treatment of Alzheimer's disease (AD). The designed scaffold has blood brain barrier penetrating ability, acetylcholinesterase (AChE) and matrix metalloproteinase-2 (MMP-2) inhibition potential. Compounds 52 and 46 showed very significant inhibition against AChE, IC 50  = 32.45 ± 0.044, 28.65 ± 0.029, BuChE, IC 50  = 157.95 ± 0.264, 160.58 ± 0.082 and MMP-2, IC 50  = 36.83 ± 0.015, 19.57 ± 0.005 (nM). In the enzyme kinetics study, lead molecule 46 showed non-competitive inhibition of AChE with K i  = 7 nM and competitive inhibition of MMP-2 with K i  = 20 nM. Compounds 52 and 46 inhibited AChE-induced Aβ aggregation at 20 μM. The compounds also exhibited in-vitro antioxidant potential in DPPH assay. Further, compound 46 was found to be a promising neuroprotective agent in MC65 cells. Lead molecule 46 significantly enhanced working memory in scopolamine induced amnesia animal model at dose of 5 mg/kg dose. The mitochondrial membrane potential was restored in animals when treated with compounds 52 and 46 . [ABSTRACT FROM AUTHOR]

Debilitating neuropsychiatric and neurodegenerative conditions are associated with complex multifactorial pathophysiology. Their treatment strategies often only provide symptomatic relief, delaying disease progression without giving a complete cure. Potent and safer treatment alternatives beyond symptomatic relief are sought. Herbal supplements have surely been explored due to their multiple component nature to enhance the effect of western medications. One such well-documented nutraceutical in the ancient Greek, Chinese, and Ayurvedic medicine system known for its various medicinal benefits is Asparagus racemosus. Widely used for its lactogenic properties, A. racemosus is also cited in Ayurveda as a nervine tonic. A. racemosus based nutraceuticals have shown to possess adaptogenic, neuroprotective, antioxidant, anti-inflammatory, and nootropic activity under preclinical and clinical settings without posing significant adverse effects. A. racemosus extracts restore the perturbed neurotransmitters and prevent oxidative neuronal damage. From the available neuropharmacological researches, the physiological actions of A. racemosus can ultimately be directed for either augmentation of cognitive ability or in the management of neurological conditions such as stress, anxiety, depression, epilepsy, Parkinson's, and Alzheimer's disease. The studies focus on the multi-component extract, and the lack of standardization has been a major hurdle in preventing the allotment of reported neuropharmacological activity to one of the phytoconstituent. Herbal standardization of the plant extract based on a specific biomarker can help elucidate the intricate biomolecular pathway and neurocircuitries being involved. This, followed by rigorous standardized clinical trials, fixing dosages, and determining contraindications would facilitate the translation of A. racemosus to a FDA-approved neuromedicine for neurological disorders. [Display omitted] • With more than 200 Asparagus species, A. racemosus is traditionally a galactagogue. • A. racemosus based neuro-nutraceuticals have nootropic and neuroprotective effects. • It possesses adaptogenic properties. • A. racemosus did not exhibit acute or sub-acute toxicity in rats. • The extracts need to be standardized for the reproducibility of results. [ABSTRACT FROM AUTHOR]

Alzheimer's disease (AD) is multifactorial, progressive neurodegeneration with impaired behavioural and cognitive functions. The multitarget-directed ligand (MTDL) strategies are promising paradigm in drug development, potentially leading to new possible therapy options for complex AD. Herein, a series of novel MTDLs phenylsulfonyl-pyrimidine carboxylate (BS-1 to BS-24) derivatives were designed and synthesized for AD treatment. All the synthesized compounds were validated by 1HNMR, 13CNMR, HRMS, and BS-19 were structurally validated by X-Ray single diffraction analysis. To evaluate the plausible binding affinity of designed compounds, molecular docking study was performed, and the result revealed their significant interaction with active sites of acetylcholinesterase (AChE) and butyrylcholinesterase (BuChE). The synthesized compounds displayed moderate to excellent in vitro enzyme inhibitory activity against AChE and BuChE at nanomolar (nM) concentration. Among 24 compounds (BS-1 to BS-24), the optimal compounds (BS-10 and BS-22) displayed potential inhibition against AChE; IC 50 = 47.33 ± 0.02 nM and 51.36 ± 0.04 nM and moderate inhibition against BuChE; IC 50 = 159.43 ± 0.72 nM and 153.3 ± 0.74 nM respectively. In the enzyme kinetics study, the compound BS-10 displayed non-competitive inhibition of AChE with Ki = 8 nM. Respective compounds BS-10 and BS-22 inhibited AChE-induced Aβ 1-42 aggregation in thioflavin T-assay at 10 μM and 20 μM, but BS-10 at 10 μM and 20 μM concentrations are found more potent than BS-22. In addition, the aggregation properties were determined by the dynamic light scattering (DLS) and was found that BS-10 and BS-22 could significantly inhibit self-induced as well as AChE-induced Aβ 1-42 aggregation. The effect of compounds (BS-10 and BS-22) on the viability of MC65 neuroblastoma cells and their capability to cross the blood-brain barrier (BBB) in PAMPA-BBB were further studied. Further, in silico approach was applied to analyze physicochemical and pharmacokinetics properties of the designed compounds via the SwissADME and PreADMET server. Hence, the novel phenylsulfonyl-pyrimidine carboxylate derivatives can act as promising leads in the development of AChE inhibitors and Aβ disaggregator for the treatment of AD. [Display omitted] • A series of 24 phenylsulfonyl-pyrimidine carboxylate derivatives were designed and synthesized. • All compounds showed moderate to excellent in vitro inhibitory activity against AChE and BuChE at nanomolar concentration. • Two compounds BS-10 and BS-22 exhibited promising AChE inhibition. • Highlighted compounds BS-10 and BS-22 significantly inhibited Aβ aggregation. • BS-10 and BS-22 displayed high potential for BBB permeability. • BS-10 and BS-22 exhibited significant neuroprotection towards MC65 cells while no neurotoxicity. [ABSTRACT FROM AUTHOR]

The diverse nature of Alzheimer's disease (AD) has prompted researchers to develop multi-functional agents. Herein, we have designed and synthesized molecular hybrids of 2-pyridylpiperazine and 5-phenyl-1,3,4-oxadiazoles. Biological activities of synthesized compounds suggested significant and balanced inhibitory potential against target enzymes. In particular, compound 49 containing 2,4-difluoro substitution at terminal phenyl ring considered as most potential lead with inhibition of acetylcholinesterase (hAChE, IC 50 = 0.054 μM), butyrylcholinesterase (hBChE, IC 50 = 0.787 μM) and beta-secretase-1 (hBACE-1, IC 50 = 0.098 μM). The enzyme kinetics study of 49 against hAChE suggested a mixed type of inhibition (Ki = 0.030 μM). Also, 48 and 49 showed significant displacement of propidium iodide from the peripheral anionic site (PAS) of hAChE, excellent blood-brain barrier (BBB) permeability in parallel artificial membrane permeation assay (PAMPA), and neuroprotective ability against SH-SY5Y neuroblastoma cell lines. Further, 49 also exhibited anti-Aβ aggregation activity in self- and AChE-induced thioflavin T assay, which was ascertained by morphological characterization by atomic force microscopy (AFM). Moreover, in vivo behavioral studies signified learning and memory improvement by compound 49 in scopolamine- and Aβ-induced cognitive dysfunctions performed on Y-maze and Morris water maze. The ex vivo studies suggested decreased AChE activity and antioxidant potential of compound 49 , with good oral absorption characteristics ascertained by pharmacokinetic studies. Image 1 • Design and synthesis of 2-pyridylpiperazine and 5-phenyl-1,3,4-oxadiazoles hybrids. • Compounds 48 and 49 exhibited balanced inhibition of AChE and BACE-1. • Propidium iodide displacement and inhibition of Aβ aggregation by 48 and 49. • Ex vivo study of rat hippocampal homogenates suggested antioxidant potential. • Amelioration of scopolamine- and Aβ-induced cognitive impairment in AD rat models. [ABSTRACT FROM AUTHOR]

Alzheimer's disease (AD) is associated with multifactorial neuropathological conditions, which include cholinergic deficit, amyloid-beta plaques formation, loss of neuronal plasticity and neuronal death. Treating such multifactorial conditions with a single target directed approach is considered to be inadequate. Accordingly, multi-target directed ligand (MTDL) strategy has been evolved as an auspicious approach for the treatment of AD. In light of that, a library of 2-substituted benzo[d]oxazol-5-amine derivatives (29-39 ; 86-107) was designed using the scaffold hopping guided MTDLs strategy, synthesized and evaluated through various in-vitro and in-vivo biological studies. The optimal compound 92 exhibited potent inhibitory activities against AChE (IC 50 = 0.052 ± 0.010 μM), BuChE (IC 50 = 1.085 ± 0.035 μM), and significant amyloid-beta aggregation (20 μM) inhibition. The compound possessed better blood-brain barrier permeability (Pe = 10.80 ± 0.055 × 10−6 cm s−1) in PAMPA assay and neuro protective properties (40 μM) on SH-SY5Y neuroblastoma cell lines. Furthermore, in-vivo behavioural studies were performed on Y-maze test (scopolamine-induced amnesia model) and Morris water maze test (Aβ 1-42 induced ICV rat model). The compound 92, at a dose of 10 mg/kg oral administration, demonstrated a substantial improvement of the cognitive and special memory impairment. In summary, both in-vitro and in-vivo investigations evidenced that compound 92 was a potential lead for the discovery of safe and effective disease-modifying agents for AD. Image 1 • Development of a library of 2-substituted benzo[d]oxazol-5-amine analogs by scaffold hopping guided MTDL & their synthesis. • Synthesized derivatives were evaluated through various in-vitro and in-vivo studies. • Compounds 92 exhibited inhibition of AChE, BuChE, Aβ 1-42 aggregation and neuroprotective properties. • Compound 92 represents a beneficial lead for the discovery of safe and effective disease-modifying agents for AD. [ABSTRACT FROM AUTHOR]

• Development of acetyl cholinesterase inhibitors by fragment growing strategy driven de novo drug design approach. • Novel 3,5-diarylpyrazole analogs and hit optimization studies of spiropyrazoline derivatives were reported. • Compounds 44 and 67 exhibited inhibition of AChE, BuChE and Aβ 1-42 aggregation. • Compound 67 represents a beneficial hit compound for development of new chemical entities for cholinesterase inhibition. Cholinergic hypothesis of Alzheimer's disease has been advocated as an essential tool in the last couple of decades for the drug development. Here in, we report de novo fragment growing strategy for the design of novel 3,5-diarylpyrazoles and hit optimization of spiropyrazoline derivatives as acetyl cholinesterase inhibitors. Both type of scaffolds numbering forty compounds were synthesized and evaluated for their potencies against AChE, BuChE and PAMPA. Introduction of lipophilic cyclohexane ring in 3,5-diarylpyrazole analogs led to spiropyrazoline derivatives, which facilitated and improved the potencies. Compound 44 (AChE = 1.937 ± 0.066 µM; BuChE = 1.166 ± 0.088 µM; hAChE = 1.758 ± 0.095 µM; P e = 9.491 ± 0.34 × 10−6 cm s1) showed positive results, which on further optimization led to the development of compound 67 (AChE = 0.464 ± 0.166 µM; BuChE = 0.754 ± 0.121 µM; hAChE = 0.472 ± 0.042 µM; P e = 13.92 ± 0.022 × 10−6 cm s1). Compounds 44 and 67 produced significant displacement of propidium iodide from the peripheral anionic site (PAS) of AChE. They were found to be safer to MC65 cells and decreased metal induced Aβ 1-42 aggregation. Further, in-vivo behavioral studies, on scopolamine induced amnesia model, the compounds resulted in better percentage spontaneous alternation scores and were safe, had no influence on locomotion in tested animal groups at dose of 3 mg/kg. Early pharmacokinetic assessment of optimized hit molecules was supportive for further drug development. [ABSTRACT FROM AUTHOR]