μM For Acetylcholinesterase Research Articles

Novel Dual Acetyl- and Butyrylcholinesterase Inhibitors Based on the Pyridyl–Pyridazine Moiety for the Potential Treatment of Alzheimer’s Disease

Background: Alzheimer’s disease (AD) is characterized by cholinergic dysfunction, making the inhibition of acetylcholinesterase (AChE) and butyrylcholinesterase (BuChE) critical for improving cholinergic neurotransmission. However, the development of effective dual inhibitors remains challenging. Objective: This study aims to synthesize and evaluate novel pyridazine-containing compounds as potential dual inhibitors of AChE and BuChE for AD treatment. Methods: Ten novel pyridazine-containing compounds were synthesized and characterized using IR, 1H NMR, and 13C NMR. The inhibitory activities against AChE and BuChE were assessed in vitro, and pharmacokinetic properties were explored through in silico ADME studies. Molecular dynamics simulations were performed for the most active compound. Results: Compound 5 was the most potent inhibitor, with IC50 values of 0.26 µM for AChE and 0.19 µM for BuChE, outperforming rivastigmine and tacrine, and showing competitive results with donepezil. Docking studies revealed a binding affinity of −10.21 kcal/mol to AChE and -13.84 kcal/mol to BuChE, with stable interactions confirmed by molecular dynamics simulations. In silico ADME studies identified favorable pharmacokinetic properties for compounds 5, 8, and 9, with Compound 5 showing the best activity. Conclusions: Compound 5 demonstrates strong potential as a dual cholinesterase inhibitor for Alzheimer’s disease, supported by both in vitro and in silico analyses. These findings provide a basis for further optimization and development of these novel inhibitors.

Green synthesis of Tacrine modified Schiff bases as anti-Alzheimer Agents: An effective strategy validated through in-silico and in-vitro analysis

A variety of Tacrine-modified Schiff base analogues were developed via solvent free (green) method and structurally elucidated using 1HNMR, FTIR and UV–Vis analysis. High product yield was obtained from the synthesised molecules, which were produced efficiently at room temperature without the need of a solvent. The developed molecules were subsequently assessed for their potential to inhibit acetylcholinesterase (AChE) and butyrylcholinesterase (BChE). These molecules revealed effective inhibition of AChE and BChE enzymes with IC50 values varying from 0.1 ± 0.02 to 0.3 ± 0.03 μM and 0.065 ± 0.01 to 0.3 ± 0.03 μM respectively. Compared to the standard Tacrine which has IC50 values of 0.35 ± 0.02 μM for AChE and 0.1 ± 0.01 μM for BChE. Notably, compound 3f showed strong inhibition among others for both the enzymes. The structure–activity relationship of derivatives synthesized were verified and established through molecular docking studies. Theoretical ADME studies also predicted excellent drug-likeness for all the synthesized molecules. Antioxidant activities were also assessed because elevated oxidative stress levels are linked with cognitive loss in Alzheimer's disease (AD). These findings suggest that the lead compound is potentially an effective inhibitor for the therapeutic management of AD.

Discovery of thiourea based acetylcholinesterase inhibitors and antibacterial agents: Synthesis, in vitro, structure-activity relationship and in silico study

In current work, we have synthesized a novel class of compounds (1-6) and assessed their acetylcholinesterase and antibacterial investigations to find out the most potent analogs. In this series, only two analogs were found to be the most potent against acetylcholinesterase and antibacterial activity. Analog (1, 25.35 ± 0.21 µM for acetylcholinesterase, ZOI 18.167 ± 0.7638 mm & MIC 149 μg/cm3 for antibacterial) & (6, 45.81 ± 0.02 µM acetylcholinesterase, ZOI 13.10 ± 0.5568 mm & MIC 180 μg/cm3 for antibacterial) shown to be the highest activity against both of them. In order to investigate the binding affinity of active residue molecular docking study. While the docking score energy for compounds 5, and 6 were the highest ones obtained for compound 5 was -8.2214 kcal/mol with an RMDS refine of 1.5843, while compound 6 was -8.0047 kcal/mol, with an RMDS refine of 1.3806.All of the above results confirm the analogue 5 & 6 are index as more potent than the others. Furthermore, all of the synthesized are characterized through modern spectroscopic techniques such as NMR and FTIR. In the future these are further assessed their cytotoxic effects and many more.

Medicinal perspectives, molecular docking and structure activity relationship of benzothiazole derived thiazole-based bis-benzohydrazide as potential anti-Alzheimer agents

A new series of benzothiazole derived thiazole-based bis-benzohydrazide hybrid (1–20) analogs were synthesized. Initially, the product confirmation was identified by employing TLC and the basic skeleton of the new hybrid synthesized compounds was further confirmed through spectroscopic techniques such as 13CNMR, 1HNMR and HREI-MS. Moreover, the synthesized analogs were tested for their inhibitory activities against acetylcholinesterase and butyrylcholinesterase. In the whole series, compounds 1, 2, 3 and 6 were found with potent activity against acetylcholinesterase (AChE), and butyrylcholinesterase (BuChE). Molecular docking inveatigation of the potent compounds was performed within the active site of acetylcholinesterase and butyrylcholinesterase revealing compounds 1, 2, 3 and 6 showing promising binding orientations against both enzymes as compared to reference drug donepezil with their IC50 values 1(2.20 ± 1.40 and 3.18 ± 0.45 μM), 2 (2.89 ± 1.25 and 2.78 ± 1.49 μM), 3 (2.94 ± 1.10 and 3.07 ± 1.23 μM), 6 (5.83 ± 1.45 and 6.03 ± 3.08 μM), respectively, and reference drug (IC50 = 8.73 ± 2.68 and 9.30 ± 2.60 μM for acetylcholinesterase and butyrylchlinesterase, respectively. In addition, ADME studies were conducted to gain a deeper understanding of the functional mechanisms of a drug on a living organism. It is considered that benzothiazole derived thiazole based bis-benzohydrazide hybrid analogs (1, 2, 3, 6) might be better inhibitors of acetylcholinesterase and butyrylcholinesterase enzymes.

In silico molecular modeling and invitro 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 to0.70±0.10 µM for butyrylcholinesterase except one thatshowed 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 inorder to explore the binding interactions established byligand (active compounds) with the active residues of targeted AChE & BuChE enzyme.

Design, Synthesis, Evaluation and Toxicity Studies of Novel Acridine Derivatives in Zebra Fish Larvae

Background: Alzheimer’s disease (AD) is a complex neurodegenerative condition for which a single protein-targeting medication is not enough to provide a cure. All the medications now available for AD are palliative. FDA has approved five medications for the treatment of AD, i.e., tacrine, donepezil, galantamine, rivastigmine, and memantine. Due to hepatotoxicity, tacrine is no longer utilized in clinical practice. Due to the lack of therapeutic efficiency of single-target medications and the multifaceted etiology of AD, multitarget-directed ligands have been developed. Objectives: The present research focused on incorporating a flavone nucleus into the amino group of 9-amino acridine nucleus to make it an acetylcholinesterase (AChE) and butyryl cholinesterase inhibitor (BuChE) with less toxicity Methods: We designed and synthesized ten flavone-substituted acridine derivatives and evaluated them for in vitro AChE and BuChE inhibitory activity. Molecular modeling studies were conducted using AutoDock Vina with hAChE (PDB ID: 4EY7) and hBuChE (PDB ID: 4TPK). The toxicity profile of the most active novel compound tested on zebrafish larvae for determining the liver and cardiac toxicity and LD50 value of the compound were determined. Results: In vitro AChE and BuChE inhibitory study by Ellman assay showed acceptable results. The compound AF2 showed the highest activity with an IC50 value of 0.99 ± 0.1 µM for AChE and 1.78 ± 0.19 for BuChE. The in vivo acute toxicity studies conducted on zebra fish larvae did not show cardiac and hepatotoxicity, and the LD50 value was found to be 1000 µL Conclusion: The results highlighted the AChE and BuChE inhibitory effects of the novel acridine-flavone hybrids, and they can be promising multitarget-directed ligands for AD.

Evaluation of 3,4-diethoxy substituted thioureas and their thiazole derivatives as potent anti-Alzheimer's agents: Synthesis, DFT, biological activity and molecular modeling investigations

The current research project aims to develop 3, 4-diethoxy substituted thioureas (15–20) and thiazoles (22–23, 25–26) analogs as potential anti-Alzheimer's agents. A total of ten derivatives were synthesized and were further characterized with TLC, FTIR, and NMR techniques. In addition, density functional theory (DFT) calculations and molecular modeling were performed to evaluate the electronic properties and anti-Alzheimer's disease potential of the compounds within the active pockets of the targeted enzymes, respectively. During in-vitro testing, it was determined that all analogs exhibited some degree of inhibitory potential, and analogs (15), (16), (19), and (26) were found to have excellent potency in inhibiting Alzheimer's disease-related enzymes i.e., monoamine oxidase-A, monoamine oxidase-B, acetylcholinesterase (AChE), and butyrylcholinesterase (BChE). Analog (15) demonstrated an IC50 of 1.33 ± 0.04 µM for MAO-A; (16) showed an IC50 of 1.67 ± 0.06 µM for MAO-B, (19) represented an IC50 of 0.31 ± 0.02 µM for AChE, and (26) showed an IC50 of 0.51 ± 0.01 µM for BChE. These compounds have shown a comparable potential with the reference compounds i.e., Clorgyline (for MAO-A), Deprenyl (for MAO-B) and donepezil in case of AChE and BChE, respectively. The study also established a structure-activity relationship and determined that the potency of the analogs depends on the nature, position, number, and electron-donating/-withdrawing effects of the phenyl ring substituents. The identified compounds also exhibited strong binding interactions during molecular docking investigations. Moreover, the most potent complexes of respective targets were found stable during molecular dynamics simulation studies. The findings of the current study revealed that new thioureas and thiazoles analogs exhibited a reactive electronic property, which is essential for anti-cholinesterase activity.

Bioactivity, crystal and molecular structure of vanadyl(III) complex with N-salicyloyl − N’(3,5-ditertbutyl-2-hydroxy)benzylidene hydrazine

N-salicyloyl-N’-(3,5-ditertbutyl-2-hydroxy)benzylidene hydrazine (H3sahz) and its complex with VO(III) have been synthesized. The molecular and crystal structure of the [(VO)2(sahz)2(C2H5O)2(C2H5OH)] complex by X-ray diffraction, as well as IR and electronic spectra, EPR spectrum etc., have been studied. The structure of the investigated VO(III) complex consists of binuclear units in which the monomeric complex molecules are linked to each other through vanadyl oxygen atom. Monomeric complexes differ between themselves in the character of coordination. Both vanadium atoms have a distorted octahedral environment. The biological activity of this compound has been studied. Lastly, the activities of the studied ligand against various enzyme proteins including acetylcholinesterase (AChE), butrylcholinesterase (BChE) and α-glycosidase (α-Gly) enzyme were compared. ChE inhibitory activities of the new complex against α-Gly, AChE and BChE were determined by Tao and Ellman’s methods. The new complex was shown to have IC50 values of 42.60 µM for BChE, 91.43 µM for AChE, and 196.49 µM for α-glycosidase.

Synthesis, characterization, crystal structure, biological activities, and molecular docking study of the (NHC)Pd(II)(Morp) (NHC: N-heterocyclic carbene, Morp: Morpholine) complexes

In this paper, a new palladium-based (NHC)Pd(II)(Morp) complexes (NHC: N-heterocyclic carbene, Morp: morpholine) were prepared. The NHC ligand in these complexes bears the 2-chloro-4-fluorobenzyl group. All complexes were fully characterized by 1H, 13C NMR, FTIR spectroscopic and elemental analysis methods. The crystal structure of complex 1f has been determined by using single-crystal X-ray diffraction. Furthermore, all complexes were investigated for their ability to inhibit enzymes. All complexes exhibited highly potent inhibition effects on acetylcholinesterase (AChE) and butyrylcholinesterase (BChE) enzymes (Ki values are in the range of 97.84 ± 8.97 to 132.28 ± 11.63 µM and 18.24 ± 2.08 to 39.08 ± 5.28 µM for AChE and BChE, respectively). Designing of reported complexes is impacted by molecular docking study, because with molecular docking study, it will lead to future researches by illuminating the interaction mechanism of complexes 1a, 1b, 1c and 1f with potential activity against target AChE and BChE enzymes at molecuar level.

New benzimidazole based Schiff bases as potent anti-alzheimer agents: Synthesis, bio-evaluation and molecular docking study

In search of potent anti-Alzheimer agent benzimidazole based Schiff base derivatives (1–18) were synthesized and evaluated as dual inhibitor for acetylcholinesterase and butyrylcholinesterase enzymes. All analogs among the series except analog 1 and 16 showed a variable degree of inhibitory activity with IC50 value ranging between 0.10 ± 0.01 to 12.40 ± 0.30 µM for acetylcholinesterase and 0.20 ± 0.01 to 11.10 ± 0.30 µM for butyrylcholinesterase. The most potent analog found among the series was analog 8 having IC50 value 0.10 ± 0.01 and 0.20 ± 0.01 µM for both acetylcholinesterase and butyrylcholinesterase inhibition respectively. The structures of all synthesized analogs were confirmed through NMR and HR-EIMS. Structure activity relationship (SAR) has been established for all newly synthesized derivatives. To understand the binding interaction of most active derivatives with enzyme active site, molecular docking study were performed. The toxicity and mutagenicity of compound 8 was predicted using in silico software, namely Derek Nexus® (version 6.3). Various toxicity endpoints, including chromosomal damage, skin sensitization, hepatotoxicity were predicted. The degradation profile of compound 8 was predicted in silico by Zeneth software (version 9.0.1) resulting in a probability of the formation of seven potential degradation products.

Design, synthesis, and evaluation of novel bistrifluoromethyl-based hydrazones as dual inhibitors of acetylcholinesterase and carbonic anhydrase enzymes for Alzheimer's disease.

In this project, non-sulfonamide bistrifluoromethyl-derived hydrazide-hydrazones were synthesized as multi-target-directed ligands to treat Alzheimer's disease and then, the novel derivatives were characterized by diverse spectral methods. Acetylcholinesterase (AChE), and human carbonic anhydrase (hCA) inhibitory qualifications of these compounds were determined. The reported compounds (2a-y) were determined to be effective inhibitors of the hCA I, hCA II and AChE enzymes with Ki values in the range of 1.130 ± 0.15-5.440 ± 0.93 μM for hCA I, 0.894 ± 0.05-6.647 ± 1.35 μM for hCA II, and 0.196 ± 0.03-4.222 ± 1.04 μM for AChE. In silico studies were also performed to illuminate the binding interactions.

Biological andcomputational evaluation of novel benzofuranyl derivatives as acetylcholinesterase and butyrylcholinesterase inhibitors.

Aim: A highly efficient one-step method has been developed for the synthesis of benzofuranyl derivatives from 2-benzoylcyclohexane-1-carboxylic acid derivatives using chlorosulfonyl isocyanate. This novel method provides a practical, cost-effective and efficient approach. Materials & methods: The inhibitory effects of benzofuranyl derivatives on acetylcholinesterase (AChE) and butyrylcholinesterase (BChE) enzymes were investigated. Ki values were determined to range from 0.009 to 0.61μM for AChE and 0.28 to 1.60μM for BChE. Molecular docking analysis provided insights into the interaction modes and binding patterns of these compounds with AChE and BChE. Conclusion: Kinetic findings of our study suggest that some of our compounds exhibited more effective low micromolar inhibition compared with the reference, and these derivatives could be usedto design more powerful agents.

Indole‐3‐carbinol (I3C): Inhibition Effect on Monoamine Oxidase A (MAO‐A), Monoamine Oxidase B (MAO‐B) and Cholinesterase Enzymes, Antioxidant Capacity and Molecular Docking Study

AbstractMonoamine oxidase A and B (MAO‐A and MAO‐B) isoenzymes play key roles in neurodegenerative diseases like Parkinson's disease (PD) and Alzheimer's disease (AD), arising from dopamine metabolism defects. Acetylcholinesterase (AChE) catalyzes acetylcholine (ACh) metabolism, linked to AD. This study investigated indole‐3‐carbinol (I3C) for in vitro inhibition on AChE, BChE, MAO‐A, and MAO‐B. In inhibition studies, I3C showed potent inhibitory potential against AChE and BChE enzymes (IC50 values of 239.29 μM and 21.51 μM, respectively). Corresponding Ki values were 243.52 μM for AChE and 2.78 μM for BChE, indicating significant inhibitory activity. Additionally, I3C effectively inhibited MAO‐A and MAO‐B enzymes (IC50 values of 19.52 μM and 40.05 μM, respectively). Its antioxidant and radical scavenging capabilities were assessed using various methods, including Fe3+‐Fe2+ reducing capacity, cupric ion (Cu2+) reduction by Cuprac method, reducing capacity by FRAP method, 1,1‐diphenyl‐2‐picryl‐hydrazyl free radical (DPPH⋅) scavenging method, and 2,2'‐azino‐bis(3‐ethylbenzthiazoline‐6‐sulfonic acid) radical (ABTS⋅+) scavenging. I3C showed potent inhibitory effects on AChE, BChE, MAO‐A, and MAO‐B enzymes. Additionally, I3C displayed a strong antioxidant capacity, suggesting its therapeutic potential as an antioxidant agent. Molecular docking simulations provided insights into I3C′s interactions with the target enzymes, informing the design of novel therapeutic agents for neurodegenerative diseases.

Synthesis, biological evaluation and molecular docking study of oxindole based chalcone analogues as potent anti-Alzheimer agents

With the goal of developing potential cholinesterase pharmaco-therapeutics, a new class of thirty analogs oxindole-based chalcone were synthesized by reacting nitro substituted oxindole with various substituted benzaldehyde in the presence of a base in ethanol under reflux conditions. All the synthesized analogs were characterized through different spectroscopic and spectrometric techniques such as 1H NMR, 13C NMR, HREI-MS and tested for their ability to inhibit acetylcholinesterase and butyrylcholinesterase that exhibited a variable degree of inhibitory potential with IC50 values ranging from 0.20 ± 0.010 to 11.20 ± 0.30 µM for acetylcholinesterase and 0.30 ± 0.010 μM to 13.20 ± 0.30 µM for butyrylcholinesterase as compared to the standard drug donepezil (IC50 value 2.16 ± 0.12 and 4.5 ± 0.11 µM respectively). Analog 22 is the most potent among the series having an IC50 value 0.10 ± 0.010 µM for acetylcholinesterase and 0.30 ± 0.010 µM for butyrylcholinesterase. Structure-activity relationship of this series has been established which is mainly based on the position and nature of the substituent on the phenyl ring. Molecular docking study was also carried out to discover the binding affinity of active derivatives with enzymes.

Design, synthesis, characterization, crystal structure, in silico studies, and inhibitory properties of the PEPPSI type Pd(II)NHC complexes bearing chloro/fluorobenzyl group

This work contains synthesis, characterization, crystal structure, and biological activity of a new series of the PEPPSI type Pd(II)NHC complexes [(NHC)Pd(II)(3-Cl-py)]. NMR, FTIR, and elemental analysis techniques were used to characterize all (NHC)Pd(II)(3-Cl-py) complexes. Also, molecular and crystal structures of complex 1c were established by single-crystal X-ray diffraction. Regarding the X-ray studies, the palladium(II) atom has a slightly distorted square-planar coordination environment. Additionally, the enzyme inhibitory effect of new (NHC)Pd(II)(3-Cl-py) complexes (1a-1g) was studied. They exhibited highly potent inhibition effect on acetylcholinesterase (AChE), butyrylcholinesterase (BChE) and carbonic anhydrases (hCAs) (Ki values are in the range of 0.08 ± 0.01 to 0.65 ± 0.06 µM, 10.43 ± 0.98 to 22.48 ± 2.01 µM, 6.58 ± 0.30 to 10.88 ± 1.01 µM and 6.34 ± 0.37 to 9.02 ± 0.72 µM for AChE, BChE, hCA I, and hCA II, respectively). Based on the molecular docking, among the seven synthesized complexes, 1c, 1b, 1e, and 1a significantly inhibited AChE, BChE, hCA I, and hCA II enzymes, respectively. The findings highpoint that (NHC)Pd(II)(3-Cl-py) complexes can be considered as possible inhibitors via metabolic enzyme inhibition.

Synthesis, in Vitro Cholinesterase Inhibition, Molecular Docking, DFT, and ADME Studies of Novel 1,3,4-Oxadiazole-2-Thiol Derivatives.

A series of 1,3,4-oxadiazole-2-thiol derivatives bearing various alkyl or aryl moieties were designed, synthesized, and characterized using modern spectroscopic methods to yield 17 compounds (6a-6q) that were screened for acetylcholinesterase (AChE) and butyrylcholinesterase (BChE) enzymes in the search for 'lead' compounds for Alzheimer's disease treatment (AD). The compounds 6q, 6p, 6k, 6o, and 6l showed inhibitory capability against AChE and BChE, with IC50 values ranging from 11.73±0.49 to 27.36±0.29 μM for AChE and 21.83±0.39 to 39.43±0.44 μM for BChE, inhibiting both enzymes within a limited range. The SAR ascertained that the substitution of the aromatic moiety had a profound effect on the AChE and BChE inhibitory potential as compared to the aliphatic substitutions which were supported by the molecular docking studies. The drug-likeness of the most synthesized compounds was confirmed by in silico ADME investigations. These results were additionally supplemented by the molecular orbital analysis (HOMO-LUMO) and electrostatic potential maps got from DFT calculations. ESP maps expose that on all structures, there are two potential binding sites conquered by the most positive and most negative districts.

Synthesis of benzimidazole derivatives containing amide bond and biological evaluation as acetylcholinesterase, carbonic anhydrase I and II inhibitors

Acetylcholinesterase (AChE) and carbonic anhydrase I (CA-I) and II (CA-II) are two vital metabolic enzymes. AChE inhibitors are seen as target molecules in drug development studies for Alzheimer's treatment. CA inhibitors are target molecules for treating many diseases from glaucoma to cancer. For this reason, it is crucial to identify new AChE and CA inhibitors. In this study, four benzimidazole acetamide derivatives were synthesized and their inhibition effects were investigated against human erythrocyte carbonic anhydrase I (hCA-I), II (hCA-II), and AChE. IC50 values of 9a-10b were determined in the range of 0.936 to 17.07 µM for AChE. IC50 values of 9a–10b for hCA-I were found as 7.21 µM, 4.72 µM, 6.08 µM, 8.23 µM, respectively. On the other hand, IC50 values of 9a–9b for hCA-II were found as 8.64 µM, 7.07 µM, 4.12 µM, 5.93 µM, respectively. According to IC50 values, 9a–10b molecules exhibited strong inhibition effects for AChE and hCAI, II. Also, Molecular docking studies were carried out to explain the binding interaction of 9a–10b with AChE, hCA-I, and hCA-II.

Study on the novel usnic acid derivatives: Design, synthesis, X-Ray crystal structure of Cu(II) complex and anti-AD activities

More and more evidence suggested that bio-metals including iron, zinc and copper play an important role in Alzheimer's disease (AD). Metal chelation agents may play an important role through promoting the metal homeostasis for AD treatment. In this study, UA (usnic acid), a natural product with antioxidant activity and metal chelation sites was selected as a lead compound. Different types of tertiary amine groups were introduced to synthesize four UA derivatives 1–4 as metal chelators and cholinesterase inhibitors since tertiary amine moiety was the key pharmacophore to inhibit cholinesterase. And the related activities such as antioxidant, anti-cholinesterase and metal chelation were evaluated. Results showed that 1–4 displayed excellent anti-oxidant activity, with lowest IC50 of 0.433 µM for ·OH scavenging ability and 8.808 µM for ·O2− scavenging ability. The mechanisms of anti-oxidant activities were furtherly studied by cyclic voltammetry. Besides, 1–4 also showed good anti-cholinesterase activities with lowest IC50 of 0.269 µM for acetylcholinesterase (AChE) and 0.361 µM for butyrylcholinesterase (BuChE). The results of molecular docking with AChE and BuChE were consistent with the experimental results. 1–4 displayed obvious chelating abilities with Cu(II) and Fe(III) by UV–vis spectra analysis and the metal complexes also showed good anti-AD activities. Interestingly, single crystal of Cu(II) complex of the hydrolyzed mono-substituted ligand was obtained which further substantiated the metal binding ability and provided clues to the anti-AD activities of the metal complex. Meanwhile, hydrolysis ratio of 4 was also tested by HPLC. Finally, BBB permeability of 1–4 was acceptable by ADMET prediction. Overall, these findings demonstrated that compounds 1–4 might be considered as potential candidates in the anti-AD therapy.

A new specific method for isolation of tomentosin with a high yield from Inula viscosa (L.) and determination of its bioactivities.

Tomentosin, the characteristic component of Inula viscosa (L.) is an important sesquiterpene lactone with anticarcinogenic effects. Methods of obtaining pure tomentosin are not sufficient for anticancer drug research. This study aims to develop a specific method to isolate tomentosin from I. viscosa with high yield. It also aims to investigate the inhibitory effects of tomentosin on human carbonic anhydrase I (hCAI), human carbonic anhydrase II (hCAII), acetylcholinesterase (AChE), butyrylcholinesterase (BChE), α-glucosidase, and α-amylase enzymes. Tomentosin was purified by a specific column chromatography method. The content of tomentosin in dichloromethane, dichloromethane by Soxhlet method, ethanol and ethanol by Soxhlet method extracts of I. viscosa was determined by liquid chromatography-tandem mass spectrometry (LC-MS/MS). Half maximal inhibitory concentration (IC50 ) and inhibition constant (Ki ) values were calculated to determine in vitro enzyme inhibition effects. Tomentosin was isolated in high yield (0.64%). The IC50 and Ki values for tomentosin were calculated as 5.00 ± 0.19 (r = 0.9688) and 4.62 ± 0.10μM for hCAI, 5.40 ± 0.26 (r = 0.9677) and 5.22 ± 0.31 μM for hCAII, 6.75 ± 0.208 (r = 0.9891) and 3.75 ± 0.27 μM for AChE, 6.67 ± 0.307 (r = 0.9820) and 0.51 ± 0.11 μM for BChE, 26.61 ± 0.236 (r = 0.9815) and 2.61 ± 0.71 μM for α-glucosidase and 26.89 ± 1.54 μM (r = 0.9670) for α-amylase, respectively. Tomentosin was isolated in high yield from the paste-like extract of I. viscosa compared to the positive controls, it was determined that tomentosin was weakly effective against hCAI, hCAII, AChE and BChE, but thoroughly effective against α-glucosidase and α-amylase. These results suggested that tomentosin has α-glucosidase and α-amylase inhibitor potential.

Site-activated multi target iron chelators with acetylcholinesterase (AChE) and monoamine oxidase (MAO) inhibitory activities for Alzheimer's disease therapy.

The first class of site-activated chelators with dual inhibition of acetyl-cholinesterase (AChE) and monoamine oxidase (MAO), rationally designed for simultaneously targeting the multiple pathogenic processes in Alzheimer's disease (AD) without significantly disrupting healthy metal metabolism in the body are discussed. It is demonstrated that the novel prochelator 2 was a selective and potent MAO-A inhibitor in vitro (IC50: 0.0077 ± 0.0007μM) with moderate inhibition of MAO-B (IC50: 7.90 ± 1.34μM). In vitro prochelator 2 also selectively inhibited AChE in a time-dependent manner and reach maximum inhibition of AChE after 2h preincubation (IC50: 0.52 ± 0.07μM for AChE, versus 44.90 ± 6.10μM for BuChE). Prochelator 2 showed little affinity for metal (Fe, Cu, and Zn) ions until it bound to and was activated by AChE that is located predominately in the brain, releasing an active iron chelator M30. M30 is an efficient chelator for metal (Fe, Cu, and Zn) ions with the capabilities to suppress oxidative stress, to selectively inhibit MAO-A and B in the brain, and to regulate cerebral biometals dyshomeostasis in vivo; M30 is also a neuroprotective-neurorestorative chelator with a broad spectrum of activities against β-amyloid (Aβ) generation, amyloid plaques and neurofibrillary tangles (NFT) formation, and Aβ aggregation induced by metal (Cu and Zn) ions. Both M30 and prochelator 2 were not toxic to Human SH-SY5Y neuroblastoma cells at low concentrations, but prochelator 2 shows limited cytotoxicity, at high concentrations. Together, these data suggest that prochelator 2 is a promise lead for simultaneously modulating multiple targets in AD.