Radiosynthesis and whole-body distribution in mice of a 18 F-labeled azepino[4,3-b]indole-1-one derivative with multimodal activity for the treatment of Alzheimer's disease.

Recently, the azepino[4,3-b]indole-1-one derivative 1 showed in vitro nanomolar inhibition against butyrylcholinesterase (BChE), the ChE isoform that plays a role in the progression and pathophysiology of Alzheimer's disease (AD), and protects against N-methyl- d-aspartate-induced neuronal toxicity. Three 9-R-substituted (R = F, Br, OMe) congeners were investigated. The 9-F derivative (2a) was found more potent as BChE inhibitors (half-maximal inhibitory concentration value = 21 nM) than 2b (9-Br) and 2c (9-OMe), achieving a residence time (38 s), assessed by surface plasmon resonance, threefold higher than that of 1. To progress in featuring the in vivo pharmacological characterization of 2a, herein the 18 F-labeled congener 2a was synthesized, by applying the aromatic 18 F-fluorination method, and its whole-body distribution in healthy mice, including brain penetration, was evaluated through positron emission tomography imaging. [18 F]2a exhibited a rapid and high brain uptake (3.35 ± 0.26% ID g-1 at 0.95 ± 0.15 min after injection), followed by a rapid clearance (t1/2 = 6.50 ± 0.93 min), showing good blood-brain barrier crossing. After a transient liver accumulation of [18 F]2a, the intestinal and urinary excretion was quantified. Finally, ex vivo pharmacological experiments in mice showed that the unlabeled 2a affects the transmitters' neurochemistry, which might be favorable to reverse cognition impairment in mild-to-moderate AD-related dementias.

Benzofuran Derivatives from Cortex Mori Radicis and Their Cholinesterase-Inhibitory Activity.

The phytochemical investigation of Cortex Mori Radicis led to the isolation and identification of a new prenylated benzofuranone (1) and four ring-opening derivatives (2-5) named albaphenol A-E, as well as nigranol A (6), together with ten 2-arylbenzofuran derivatives (7-16). The characterization of the structures of the new compounds and the structural revision of nigranol A (6) were conducted using the comprehensive analysis of spectroscopic data (1D/2D NMR, HRESIMS, CD, and XRD). Compounds 1-16 were tested for their inhibitory effects on acetylcholinesterase (AChE) and butyrylcholinesterase (BChE). Compounds 1 and 4 showed weak BChE-inhibitory activity (IC50 45.5 and 61.0 µM); six 2-arylbenzofuran derivatives showed more-potent BChE-inhibitory activity (IC50 2.5-32.8 µM) than the positive control galantamine (IC50 35.3 µM), while being inactive or weakly inhibitory toward AChE. Cathafuran C (14) exhibited the most potent and selective inhibitory activity against BChE in a competitive manner, with a Ki value of 1.7 µM. The structure-activity relationships of the benzofuran-type stilbenes were discussed. Furthermore, molecular docking and dynamic simulations were performed to clarify the interactions of the inhibitor-enzyme complex.

Discovery of carbamate-based N-salicyloyl tryptamine derivatives as novel pleiotropic agents for the treatment of Alzheimer's disease.

In this work, based on the potential anti-AD molecule previously studied by our group, we continue to introduce different substituents at different positions to improve both drug-like properties and on target activities. 33 N-salicyloyl tryptamine-carbamate hybrids were designed, synthesized and evaluated as cholinesterase inhibitors. H327 was the most potent BChE inhibitor (eqBChE IC50 = 0.057 ± 0.005 µM), and showed threefold improved inhibitory potency than the positive drug rivastigmine (eqBChE IC50 = 0.19 ± 0.001 µM). In addition, H327 as a pseudo-irreversible BChE inhibitor was endowed with neuroprotective, antioxidative and anti-neuroinflammatory properties. Cytotoxicity and acute toxicity tests confirmed the safety of compound H327. The pharmacokinetics study showed that compound H327 had a longer T1/2 time and higher bioavailability than the lead compound 1 g. Compound H327 was able to cross the blood-brain barrier (BBB) in vivo. Moreover, the behavioral tests showed that compound H327 could significantly improve scopolamine-induced cognitive impairment in vivo. Overall, these results demonstrated that compound H327 is a promising multi-target agent for the treatment of AD.

Design and synthesis of benzodiazepine-1,2,3-triazole hybrid derivatives as selective butyrylcholinesterase inhibitors.

A new series of compounds based on benzodiazepine-1,2,3-triazole were synthesized and evaluated as cholinesterase inhibitors by Ellman's method. The compounds proved to be selective inhibitors of butyrylcholinesterase (BuChE) over acetylcholinesterase. The most potent compound was 3,3-dimethyl-11-(3-((1-(4-nitrobenzyl)-1H-1,2,3-triazol-4-yl)methoxy)phenyl)-2,3,4,5,10,11-hexahydro-1H-dibenzo[b,e][1,4]diazepin-1-one, identified as a submicromolar inhibitor of BuChE with IC50 value of 0.2 µM. In addition, the amyloid-ß self-aggregation evaluation studies for selected compounds showed potent inhibitory effects compared to donepezil. The docking and cell viability studies supported the potential of compound 9b-6 as significant BuChE inhibitor.

Design, Synthesis, and Evaluation of Acetylcholinesterase and Butyrylcholinesterase Dual-Target Inhibitors against Alzheimer's Diseases.

A series of novel compounds 6a-h, 8i-1, 10s-v, and 16a-d were synthesized and evaluated, together with the known analogs 11a-f, for their inhibitory activities towards acetylcholinesterase (AChE) and butyrylcholinesterase (BChE). The inhibitory activities of AChE and BChE were evaluated in vitro by Ellman method. The results show that some compounds have good inhibitory activity against AChE and BChE. Among them, compound 8i showed the strongest inhibitory effect on both AChE (eeAChE IC50 = 0.39 µM) and BChE (eqBChE IC50 = 0.28 µM). Enzyme inhibition kinetics and molecular modeling studies have shown that compound 8i bind simultaneously to the peripheral anionic site (PAS) and the catalytic sites (CAS) of AChE and BChE. In addition, the cytotoxicity of compound 8i is lower than that of Tacrine, indicating its potential safety as anti-Alzheimer's disease (anti-AD) agents. In summary, these data suggest that compound 8i is a promising multipotent agent for the treatment of AD.

Naphthalene-triazolopyrimidine hybrid compounds as potential multifunctional anti-Alzheimer's agents.

In an attempt to construct potential anti-Alzheimer's agents Naphthalene-triazolopyrimidine hybrids were synthesized and screened in vitro against the two cholinesterases (ChE)s, amyloid ß aggregation and for antioxidation activity. Single-crystal X-ray crystallography was utilized for crystal structure determination of one of the compounds. In vitro study of compounds revealed that most of the compounds are capable of inhibiting acetylcholinesterase and Butyrylcholinesterase activity. Particularly, the compounds 4e and 4d exhibited IC50 values ranging from 8.6 to 14 nM against AChE lower than the standard drug Donepezil (IC50 49 nM). Best result was found for compound 4e with IC50 of 8.6 nM (for AChE) and 150 nM (for BuChE). Selectivity upto that of Donepezil and even more was observed for 4a, 4c and 4h. Investigation by electron microscopy, transmission electron microscopy and ThT fluorescence assay unveils the fact that synthesized hybrids exhibit amyloid ß self-aggregation inhibition. The compounds 4i and 4j revealed highest inhibitory potential, 85.46% and 72.77% at 50 µM respectively; above the standard Aß disaggregating agent, Curcumin. Their antioxidation profile was also analyzed. Studies from DPPH free radical scavenging assay and ORAC assay depicts molecules to possess low antioxidation profile. Results suggest that triazolopyrimidines are potential candidate for Acetylcholinesterase (AChE), Butyrylcholinesterase (BuChE), and amyloid ß aggregation inhibition. In silico ADMET profiling indicates drug-like properties with a very low toxic influence. Such synthesized compounds provide a strong vision for further development of potential anti-Alzheimer's agents.

Highly selective carbamate-based butyrylcholinesterase inhibitors derived from a naturally occurring pyranoisoflavone.

This current study described the design and synthesis of a series of derivatives based on a natural pyranoisaflavone, which was obtained from the seeds of Millettia pachycarpa and displayed attractive BChE inhibition and high selectivity in our previous study. The inhibitory potential of all derivatives against two cholinesterases was evaluated. Only a few compounds demonstrated AChE inhibitory activity at the tested concentrations, while 26 compounds showed significant inhibition on BChE (the IC50 values varied from 9.34 µM to 0.093 µM), most of them presented promising selectivity to ward BChE. Prediction of ADME properties for 7 most active compounds was performed. Among them, 9g (IC50 = 222 nM) and 9h (IC50 = 93 nM) were found to be the most potent BChE inhibitors with excellent selectivity over AChE (SI ratio = 1339 and 836, respectively). The kinetic analysis demonstrated both of them acted as mixed-type BChE inhibitors, while the molecular docking results indicated that they interacted with both residues in the catalytic active site. A cytotoxicity test on PC12 cells showed that both 9g and 9h had a therapeutic safety range similar to tacrine. Overall, the results indicate that 9h could be a good candidate of BChE inhibitors.

Design, synthesis, in vitro and in vivo evaluation of novel pyrrolizine-based compounds with potential activity as cholinesterase inhibitors and anti-Alzheimer's agents.

Novel series of pyrrolizine based compounds (4-6 and 9-11) were designed, synthesized and evaluated as potential anti-Alzheimer agents. Most of the tested compounds showed selectivity to hAChE over hBChE and effectively inhibited self-induced amyloid beta aggregation in vitro. Among these derivatives, compound 10 displayed high selectivity towards hAChE (Ki = 1.47 ±â€¯0.63 µM for hAChE and Ki = 40.15 ±â€¯3.31 µM for hBChE). However, compound 11 displayed dual inhibitory effect against hAChE and hBChE at submicromolar range (Ki = 0.40 ±â€¯0.03 and 0.129 ±â€¯0.009 µM, respectively). Kinetic studies of the new ligands showed competitive type inhibition for both hAChE and hBChE. Moreover, compounds 10 and 11 showed lower or comparable cytotoxicity to donepezil against human neuroblastoma (SH-SY5Y) and normal human hepatic (THLE2) cell lines. In vivo studies confirmed that both compounds were able to improve cognitive dysfunction of scopolamine-induced AD mice. Finally, molecular docking simulation of compounds 10 and 11 in hAChE active site showed good agreement with the obtained pharmaco-biological results.

Synthesis and evaluation of coumarin/1,2,4-oxadiazole hybrids as selective BChE inhibitors with neuroprotective activity.

A series of new coumarin/1,2,4-oxadiazole hybrids were synthesized and evaluated for cholinesterase inhibitory and neuroprotective activities. Among them, enantiomers 5u and 5v showed potent hBChE inhibitory activity with IC50 values of 8.17 and 9.56 µM, respectively, and also exhibited good selectivity for hBChE over hAChE by 9.49- and 7.58-fold, respectively. In addition, both compounds could protect SH-SY5Y cells against Aß25-35-induced neurotoxicity. The preliminary bioassay results provided a new chemotype for multifunctional anti-Alzheimer's disease agents and continuing investigation into compounds 5u and 5v is warranted.

Design, synthesis and biological evaluation of benzofuran appended benzothiazepine derivatives as inhibitors of butyrylcholinesterase and antimicrobial agents.

A series of bezofuran appended 1,5-benzothiazepine compounds 7a-v was designed, synthesized and evaluated as cholinesterase inhibitors. The biological assay experiments showed that most of the compounds displayed a clearly selective inhibition for butyrylcholinesterase (BChE), while a weak or no effect towards acetylcholinesterase (AChE) was detected. All analogs exhibited varied BChE inhibitory activity with IC50 value ranging between 1.0 ±â€¯0.01 and 72 ±â€¯2.8 µM when compared with the standard donepezil (IC50, 2.63 ±â€¯0.28 µM). Among the synthesized derivatives, compounds 7l, 7m and 7k exhibited the highest BChE inhibition with IC50 values of 1.0, 1.0 and 1.8 µM, respectively. The results from a Lineweaver-Burk plot indicated a mixed-type inhibition for compound 7l with BChE. In addition, docking studies confirmed the results obtained through in vitro experiments and showed that most potent compounds bind to both the catalytic anionic site (CAS) and peripheral anionic site (PAS) of BChE active site. The synthesized compounds were also evaluated for their in vitro antibacterial and antifungal activities. The results indicated that the compounds possessed a broad spectrum of activity against the tested microorganisms and showed high activity against both gram positive and gram negative bacteria and fungi.

Synthesis and molecular docking studies of some 4-phthalimidobenzenesulfonamide derivatives as acetylcholinesterase and butyrylcholinesterase inhibitors.

A series of 4-phthalimidobenzenesulfonamide derivatives were designed, synthesized and evaluated for the inhibitory activities against acetylcholinesterase (AChE) and butyrylcholinesterase (BuChE). Structures of the title compounds were confirmed by spectral and elemental analyses. The cholinesterase (ChE) inhibitory activity studies were carried out using Ellman's colorimetric method. The biological activity results revealed that all of the title compounds (except for compound 8) displayed high selectivity against AChE. Among the tested compounds, compound 7 was found to be the most potent against AChE (IC50= 1.35 ± 0.08 µM), while compound 3 exhibited the highest inhibition against BuChE (IC50= 13.41 ± 0.62 µM). Molecular docking studies of the most active compound 7 in AChE showed that this compound can interact with both the catalytic active site (CAS) and the peripheral anionic site (PAS) of AChE.

Synthesis and preliminary biological evaluations of (+)-isocampholenic acid-derived amides.

The synthesis of two novel (+)-isocampholenic acid-derived amines has been realized starting from commercially available (1S)-(+)-10-camphorsulfonic acid. The novel amines as well as (+)-isocampholenic acid have been used as building blocks in the construction of a library of amides using various aliphatic, aromatic, and amino acid-derived coupling partners using BPC and CDI as activating agents. Amide derivatives have been assayed against several enzymes that hold potential for the development of new drugs to battle bacterial infections and Alzheimer's disease. Compounds 20c and 20e showed promising selective sub-micromolar inhibition of human butyrylcholinesterase [Formula: see text] ([Formula: see text] values [Formula: see text] and [Formula: see text], respectively).

Affinity ultrafiltration based metabolomic profiling directed discovery novel butyrylcholinesterase inhibitors from Uncaria sessilifructus.

The butyrylcholinesterase (BChE) is an attractive target for treating Alzheimer's disease. In this study, we report the discovery of five new monoterpene indole alkaloids (MIAs) along with three known analogues from Uncaria sessilifructus Roxb. as BChE inhibitors using affinity ultrafiltration based metabolomic profiling directed isolation strategy. Their structures were well identified through comprehensive spectroscopic and chiroptical analyses. Compounds 1-2 featured unique glycosidic linkages with 1,3-dioxane structure. All the compounds exhibited BChE inhibitory bioactivity without any cytotoxic effects. Enzymatic kinetic and molecular docking analyses of compounds 1 and 6 demonstrated their inhibiting mechanisms and binding patterns to BChE. These findings provide a valuable workflow for efficiently screening ligands that bind to proteins, and scientific recognition in the discovery of BChE inhibitors for treating neurodegenerative disorders.

Optimizing drug-like properties of selective butyrylcholinesterase inhibitors for cognitive improvement: Enhancing aqueous solubility by disrupting molecular plane.

Most recently, worldwide interest in butyrylcholinesterase (BChE) as a potential target for treating Alzheimer's disease (AD) has increased. In this study, the previously obtained selective BChE inhibitors with benzimidazole-oxadiazole scaffold were further structurally modified to increase their aqueous solubility and pharmacokinetic (PK) characteristics. S16-1029 showed improved solubility (3280 µM, upgraded by 14 times) and PK parameters, including plasma exposure (AUC0-inf = 1729.95 ng/mL*h, upgraded by 2.6 times) and oral bioavailability (Fpo = 48.18%, upgraded by 2 times). S16-1029 also displayed weak or no inhibition against Cytochrome P450 (CYP450) and human ether a-go-go related gene (hERG) potassium channel. In vivo experiments on tissue distribution revealed that S16-1029 could cross the blood-brain barrier (BBB) and reach the central nervous system (CNS). In vivo cognitive improvement efficacy and good in vitro target inhibitory activity (eqBChE IC50 = 11.35 ± 4.84 nM, hBChE IC50 = 48.1 ± 11.4 nM) were also assured. The neuroprotective effects against several AD pathology characteristics allowed S16-1029 to successfully protect the CNS of progressed AD patients. According to the findings of this study, altering molecular planarity might be a viable strategy for improving the drug-like property of CNS-treating drugs.

4-Oxypiperidine Ethers as Multiple Targeting Ligands at Histamine H3 Receptors and Cholinesterases.

This study examines the properties of a novel series of 4-oxypiperidines designed and synthesized as histamine H3R antagonists/inverse agonists based on the structural modification of two lead compounds, viz., ADS003 and ADS009. The products are intended to maintain a high affinity for H3R while simultaneously inhibiting AChE or/and BuChE enzymes. Selected compounds were subjected to hH3R radioligand displacement and gpH3R functional assays. Some of the compounds showed nanomolar affinity. The most promising compound in the naphthalene series was ADS031, which contained a benzyl moiety at position 1 of the piperidine ring and displayed 12.5 nM affinity at the hH3R and the highest inhibitory activity against AChE (IC50 = 1.537 µM). Eight compounds showed over 60% eqBuChE inhibition and hence were qualified for the determination of the IC50 value at eqBuChE; their values ranged from 0.559 to 2.655 µM. Therapy based on a multitarget-directed ligand combining H3R antagonism with additional AChE/BuChE inhibitory properties might improve cognitive functions in multifactorial Alzheimer's disease.

Synthesis, biological activity and molecular modeling studies on 1H-benzimidazole derivatives as acetylcholinesterase inhibitors.

A series of N-{2-[4-(1H-benzimidazole-2-yl)phenoxy]ethyl}substituted amine derivatives were designed to assess cholinesterase inhibitor activities. Acetylcholinesterase (AChE) and butyrylcholinesterase (BuChE) inhibitor activities were evaluated in vitro by using Ellman's method. It was discovered that most of the compounds displayed AChE and/or BuChE inhibitor activity and few compounds were selective against AChE/BuChE. Compound 3c and 3e were the most active compounds in the series against eeAChE and hAChE, respectively. Molecular docking studies and molecular dynamics simulations were also carried out.

Identification of sulfonamide-based butyrylcholinesterase inhibitors using machine learning.

Aim: This study reports the designing of BChE inhibitors through machine learning (ML), followed by in silico and in vitro evaluations. Methodology: ML technique was used to predict the virtual hit, and its derivatives were synthesized and characterized. The compounds were evaluated by using various in vitro tests and in silico methods. Results: The gradient boosting classifier predicted N-phenyl-4-(phenylsulfonamido) benzamide as an active BChE inhibitor. The derivatives of the inhibitor, i.e., compounds 34, 37 and 54 were potent BChE inhibitors and displayed blood-brain barrier permeability with no significant AChE inhibition. Conclusion: The ML prediction was effective, and the synthesized compounds showed the BChE inhibitory activity, which was also supported by the in silico studies.

A highly effective and stable butyrylcholinesterase inhibitor with multi-faceted neuroprotection and cognition improvement.

Butyrylcholinesterase (BChE) has been more and more attractive for treating neurodegenerative diseases, especially Alzheimer's disease (AD). In this study, we conducted activity and druggability optimization based on the structures that were previously reported. Most compounds exhibited pronounced BChE inhibitory capacity with nanomolar IC50 values. Based on the results of inhibiting activity and cyto-safety evaluations, two compounds (7, eqBChE IC50 = 2.94 nM, hBChE IC50 = 34.6 nM, and 20, eqBChE IC50 = 0.15 nM, hBChE IC50 = 45.2 nM) have been selected as candidates. High stability of compound 20 contributed to significantly improved blood concentration and tissue exposure, resulting in a reduced administration and effective dose in pharmacodynamic experiments. Two candidates exhibited remarkable neuroprotective properties and cognition improving activity, by benefiting cholinergic system, reducing the total Aß amount and increasing the ghrelin content. Simultaneous modulation in the center and periphery greatly improves the efficiency of BChE inhibitors. Considering the regulation on ghrelin level, BChE inhibition could improve not only symptoms but also nutritional status of AD patients.

Butenolide derivatives from Aspergillus terreus selectively inhibit butyrylcholinesterase.

Two undescribed butenolide derivatives, asperteretal J (1) and K (2), together with 13 known ones (3-15) were isolated from an endophytic fungus Aspergillus terreus SGP-1, the fermentation product of which exhibited selective inhibitory activity toward butyrylcholinesterase. The structures of the new compounds were elucidated based on HRMS and NMR data, and the absolute configurations were determined by specific optical rotation comparison. All compounds were evaluated for cholinesterase inhibitory effects with galantamine as a positive control. Compounds 4-8 selectively inhibited butyrylcholinesterase with IC50 values of 18.4-45.8 µM in a competitive manner, with Ki values of 12.3-38.2 µM. The structure-activity relationship was discussed. Molecular docking and dynamic simulation of the inhibitor-enzyme complex were performed to better understand the interactions.

N-methylated diazabicyclo[3.2.2]nonane substituted triterpenoic acids are excellent, hyperbolic and selective inhibitors for butyrylcholinesterase.

Triterpenoic acids (oleanolic, ursolic, betulinic, platanic and glycyrrhetinic acid) were acetylated and coupled with 1,3- or 1,4-diazabicyclo[3.2.2]nonanes to yield amides. Reaction of these amides with methyl iodide at the distal nitrogen of the bicyclic system gave the corresponding quaternary ammonium salts. These compounds were shown to act as excellent inhibitors of the enzyme butyrylcholinesterase (BChE) while being only weak inhibitors for acetylcholinesterase (AChE). Evaluation of the enzyme kinetics revealed these compounds to act as hyperbolic inhibitors for BChE while the results from molecular modeling gave an explanation for their selectivity between AChE and BChE.