Anticholinesterase activities of novel indole-based hydrazide-hydrazone derivatives: Design, synthesis, biological evaluation, molecular docking study and in silico ADME prediction

Development of new benzil-hydrazone derivatives as anticholinesterase inhibitors: synthesis, X-ray analysis, DFT study and in vitro/in silico evaluation

Alzheimer's disease (AD) is a complex neurodegenerative disorder affecting the central nervous system. Current drugs for AD have limited effectiveness and often come with side effects. Consequently, there is a pressing need to develop new, safe, and more effective treatments for Alzheimer's disease. In this work, two novel benzil-hydrazone compounds, abbreviated 2-ClMHB and 2-ClBHB, were synthesized for the first time by refluxing the benzil with 2-Chloro phenyl hydrazine and they have been tested for their in vitro anti-cholinesterase activities and in silico acetyl and butyryl enzymes inhibition. The resulting products were characterized using UV-Vis and IR spectroscopy, while the single-crystal X-ray diffraction investigation was successful in establishing the structures of these compounds. DFT calculations have been successfully made to correlate the experimental data. According to biological studies, the synthesized hydrazones significantly inhibited both butyrylcholinesterase (2-ClMHB: 20.95 ± 1.29 µM and 2-ClBHB: 31.21 ± 1.50 µM) and acetylcholinesterase (2-ClMHB: 21.80 ± 1.10 µM and 2-ClBHB: 10.38 ± 1.27 µM). Moreover, molecular docking was also employed to locate the molecule with the optimum interaction and stability as well as to explain the experimental findings. The compound's dynamic nature, binding interaction, and protein-ligand stability were investigated using molecular dynamics (MD) simulations. Analyzing parameters such as RMSD and RMSF indicated that the compound remained stable throughout the 100 ns MD simulation. Finally, the drugs displayed high oral bioavailability, as per projected ADME and pharmacokinetic parameters.

Comprehensive investigation of multiple targets in the development of newer drugs for the Alzheimer's disease

Alzheimer's disease, a significant contributor to dementia, is rapidly becoming a serious healthcare concern in the 21st century. The alarming number of patients with Alzheimer's disease is steadily increasing, which is contributed by the dearth of treatment options. The current treatment for Alzheimer's disease is heavily dependent on symptomatic treatment that has failed to cure the disease despite huge investments in the development of drugs. The clinical treatment of Alzheimer's disease with limited drugs is generally targeted towards the inhibition of N-methyl-d-aspartate receptor and acetylcholine esterase, which only elevate cognition levels for a limited period. Beyond the aforementioned molecular targets, β-amyloid was much explored with little success and thus created a feel and palpable growing emphasis on discovering new putative and novel targets for AD. This has inspired medicinal chemists to explore new targets, including microglia, triggering receptors expressed on myeloid cells 2 (Trem-2), and notum carboxylesterase, to discover new lead compounds. This review explores the functions, pathophysiological roles, and importance of all AD-related targets that address therapeutic and preventive approaches for the treatment and protection of Alzheimer's disease.

Novel hydrazide‐hydrazone containing 1,2,4‐triazole as potent inhibitors of antiapoptotic protein Bcl‐xL: Synthesis, biological evaluation, and docking studies

This study describes the synthesis and characterization of a series of novel hydrazide‐hydrazone derivatives containing a 1,2,4‐triazole ring. The compounds were characterized using various spectroscopic techniques, such as FT‐IR, 1H‐NMR, 13C‐NMR, HRMS, and elemental analysis. The antiproliferative activity of the synthesized compounds was evaluated against a panel of human cancer cell lines (HCT‐116, HepG‐2, KLN205, LTPA, U138, and SW620) and healthy cell lines (HSkMC and iPSCs). Among the compounds tested, compounds 4, 5p, 5r, and 5s showed the highest effectiveness in inhibiting the growth of cancer cells with Bcl‐xL inhibitory concentration (IC50) values. These compounds further demonstrated selective cytotoxicity against the Bcl‐xL‐dependent lymphoma cell line (DBs). Molecular docking studies were also performed to investigate the potential binding interactions of compounds 4, 5p, 5r, and 5s with the active site of Bcl‐xL (PDB ID: 7LH7, 1.4 Å). Mechanistic studies revealed that compounds 4, 5r, and 5s induced apoptosis predominantly through the intrinsic mitochondrial pathway, while compound 5p exhibited a distinct cell cycle arrest profile, impacting both the S and G2/M phases. Western blot analysis suggested that these compounds may downregulate cyclin expression, thereby blocking its association with Bcl‐xL. Overall, these results demonstrate the potential of these novel hydrazide‐hydrazone derivatives as anticancer agents with activity comparable or superior to doxorubicin and 5‐fluorouracil.

New Sulfonate Ester-Linked Fluorinated Hydrazone Derivatives as Multitarget Carbonic Anhydrase and Cholinesterase Inhibitors: Design, Synthesis, Biological Evaluation, Molecular Docking and ADME Analysis

In this study, some new hydrazone derivatives (2a-g) was designed, synthesized for first time, and evaluated as multitarget inhibitors of AChE, BChE, hCA I and hCA II. The chemical structures of new hybrids were confirmed by elemental analysis and some spectroscopic techniques. All tested compounds showed low nanomolar inhibition with IC50 values of in the range of 30.4-264.0 nM against hCA I, 23.2-251.6 nM against hCA II, 12.1-114.3 nM against AChE, and 76.4-134.0 nM against BChE. These compounds inhibited hCA I and AChE more than acetazolamide (AZA) and neostigmine. Among them, compounds 2c and 2e, which have a linear structure, were determined to be the most active inhibitor candidates against these selected enzymes. Molecular docking studies were carried out on the compounds (2a--g), revealing their binding interactions with the active site of AChE, BChE, hCA I and hCA II thus supporting the experimental findings. Additionally, in silico absorption, distribution, metabolism, and excretion (ADME) prediction studies of the obtained compounds (2a--g) with in silico approaches were carried out to determine their solubility, whether they have the potential to cross the blood-brain barrier (BBB), values such as GI absorption and drug likeness principles.

Novel hydrazide-hydrazone containing 1,2,4-triazole as potent inhibitors of antiapoptotic protein Bcl-xL: Synthesis, biological evaluation, and docking studies

This study describes the synthesis and characterization of a series of novel hydrazide-hydrazone derivatives containing a 1,2,4-triazole ring. The compounds were characterized using various spectroscopic techniques, such as FT-IR, 1H-NMR, 13C-NMR, HRMS, and elemental analysis. The antiproliferative activity of the synthesized compounds was evaluated against a panel of human cancer cell lines (HCT-116, HepG-2, KLN205, LTPA, U138, and SW620) and healthy cell lines (HSkMC and iPSCs). Among the compounds tested, compounds 4, 5p, 5r, and 5s showed the highest effectiveness in inhibiting the growth of cancer cells with Bcl-xL inhibitory concentration (IC50) values. These compounds further demonstrated selective cytotoxicity against the Bcl-xL-dependent lymphoma cell line (DBs). Molecular docking studies were also performed to investigate the potential binding interactions of compounds 4, 5p, 5r, and 5s with the active site of Bcl-xL (PDB ID: 7LH7, 1.4 Å). Mechanistic studies revealed that compounds 4, 5r, and 5s induced apoptosis predominantly through the intrinsic mitochondrial pathway, while compound 5p exhibited a distinct cell cycle arrest profile, impacting both the S and G2/M phases. Western blot analysis suggested that these compounds may downregulate cyclin expression, thereby blocking its association with Bcl-xL. Overall, these results demonstrate the potential of these novel hydrazide-hydrazone derivatives as anticancer agents with activity comparable or superior to doxorubicin and 5-fluorouracil.

Indole Derivatives: A Versatile Scaffold in Modern Drug Discovery-An Updated Review on Their Multifaceted Therapeutic Applications (2020-2024)

Indole derivatives have become an important class of compounds in medicinal chemistry, recognized for their wide-ranging biological activities and therapeutic potential. This review provides a comprehensive overview of recent advances in the evaluation of indole-based compounds in the last five years, highlighting their roles in cancer treatment, infectious disease management, anti-inflammatory therapies, metabolic disorder interventions, and neurodegenerative disease management. Indole derivatives have shown significant efficacy in targeting diverse biological pathways, making them valuable scaffolds in designing new drugs. Notably, these compounds have demonstrated the ability to combat drug-resistant cancer cells and pathogens, a significant breakthrough in the field, and offer promising therapeutic options for chronic diseases such as diabetes and hypertension. By summarizing recent key findings and exploring the underlying biological mechanisms, this review underscores the potential of indole derivatives in addressing major healthcare challenges, thereby instilling hope and optimism in the field of modern medicine.

Ultrasonic-assisted synthesis and antitumor evaluation of novel variant heterocyclic compounds based on piperidine ring

Aim: This work explores the eco-friendly synthesis of various heterocycles from a piperidine-based compound (1) and explore their potential as antitumor agents.Materials & methods: Ultrasonic irradiation was used to synthesize heterocycles like pyridone, thiophene and coumarin, with computational tools analyzing stability and biological interactions.Results: Compounds 9 and 14 exhibit strong cytotoxic activity, surpassing doxorubicin. Compounds 2, 6, 10 and 13 exhibited intermediate activity, while compounds 3, 7 and 12 had minimal effects. Docking studies suggest potential ADORA1 receptor interaction. Computational tools analyze stability and interaction with biological systems, revealing potential antitumor mechanisms.Conclusion: Green synthesis of diverse heterocycles yielded potent antitumor agents (compounds 9 & 14). DFT and Docking studies suggest interaction with ADORA1 receptor, a potential mechanism.

Discovery of novel dihydro-pyrimidine hybrids: insight into the design, synthesis, biological evaluation and absorption, distribution, metabolism and excretion studies

Aim: By keeping in aspects, the pharmacological potential of heterocyclic compounds, pyrimidine-based compounds were designed, synthesized and evaluated for α-amylase inhibitory potential.Materials & methods: Five new series 1a-l, 2a-d, 3a-d, 4a-d and 5a-d of 1,2,3,4-tetrahydroprimidine-5-carboxylate derivatives were designed by de novo method by taking Alogliptin as reference compound. Here in we describe synthesis and characterization of compounds as potential α-amylase inhibitor.Results: Structure activity relationship (SAR), in vitro analysis and molecular modelling approaches generate compounds 1 h, 1i, 1k and 4c as potential lead with good α-amylase inhibitory selection. However, compound 1k failed the criteria of optimization as drug lead by ADME studies while all other compounds showed optimum range for all in silico ADME parameters.Conclusion: Therefore, these compounds can serve as potential lead candidate in developing anti-diabetic therapy.

New 6-nitro-4-substituted quinazoline derivatives targeting epidermal growth factor receptor: design, synthesis and in vitro anticancer studies

Aim: Twenty compounds of 6-nitro-4-substituted quinazolines were synthesized.Materials & methods: The new derivatives were evaluated for their epidermal growth factor receptor (EGFR) inhibitory activity. The most potent derivatives were assessed for their cytotoxicity against colon cancer and lung cancer cells, in addition to normal fibroblast cells.Results & discussion: compound 6c showed a superior to nearly equal cytotoxicity in comparison to gefitinib, it also revealed a good safety profile. Compound 6c caused a cell cycle arrest at G2/M phase in addition to induction of apoptosis. A molecular docking study was conducted on the most active compounds to gain insights of their binding mode in the active site of EGFR enzyme besides ADME prediction of their physicochemical properties and drug likeness profile.

Indole-Based Compounds in the Development of Anti-Neurodegenerative Agents

Neurodegeneration is a gradual decay process leading to the depletion of neurons in both the central and peripheral nervous systems, ultimately resulting in cognitive dysfunctions and the deterioration of brain functions, alongside a decline in motor skills and behavioral capabilities. Neurodegenerative disorders (NDs) impose a substantial socio-economic strain on society, aggravated by the advancing age of the world population and the absence of effective remedies, predicting a negative future. In this context, the urgency of discovering viable therapies is critical and, despite significant efforts by medicinal chemists in developing potential drug candidates and exploring various small molecules as therapeutics, regrettably, a truly effective treatment is yet to be found. Nitrogen heterocyclic compounds, and particularly those containing the indole nucleus, which has emerged as privileged scaffold, have attracted particular attention for a variety of pharmacological applications. This review analyzes the rational design strategy adopted by different research groups for the development of anti-neurodegenerative indole-based compounds which have the potential to modulate various molecular targets involved in NDs, with reference to the most recent advances between 2018 and 2023.

Novel quinazolines bearing 1,3,4-thiadiazole-aryl urea derivative as anticancer agents: design, synthesis, molecular docking, DFT and bioactivity evaluations

A novel series of 1-(5-((6-nitroquinazoline-4-yl)thio)-1,3,4-thiadiazol-2-yl)-3-phenylurea derivatives 8 were designed and synthesized to evaluate their cytotoxic potencies. The structures of these obtained compounds were thoroughly characterized by IR, 1H, and 13C NMR, MASS spectroscopy and elemental analysis methods. Additionally, their in vitro anticancer activities were investigated using the MTT assay against A549 (human lung cancer), MDA-MB231 (human triple-negative breast cancer), and MCF7 (human hormone-dependent breast cancer). Etoposide was used as a reference marketed drug for comparison. Among the compounds tested, compounds 8b and 8c demonstrated acceptable antiproliferative activity, particularly against MCF7 cells. Considering the potential VEGFR-2 inhibitor potency of these compounds, a molecular docking study was performed for the most potent compound, 8c, to determine its probable interactions. Furthermore, computational investigations, including molecular dynamics, frontier molecular orbital analysis, Fukui reactivity descriptor, electrostatic potential surface, and in silico ADME evaluation for all compounds were performed to illustrate the structure-activity relationship (SAR).

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.

Hydrazone-sulfonate hybrids as potential cholinesterase inhibitors: design, synthesis and molecular modeling simulation

Aim: Design and synthesis of a series of hydrazone-sulfonate hybrids, 5a-r. Methodology: The inhibitory properties of the synthesized compounds against acetylcholinesterase and butyrylcholinesterase were evaluated using donepezil as the reference standard. Results & conclusion: Compound 5e was identified as the most potent inhibitor of acetylcholinesterase (IC50 = 9.30 μM), and compound 5i was the most potent inhibitor of butyrylcholinesterase (IC50 = 11.82 μM). To confirm the safety of the most potent hits at the used doses, toxicological bioassays were conducted. Molecular docking was performed and the tested derivatives were found to fit well in the active sites of both enzymes. This study provides valuable insights into the potential of hydrazone-sulfonate hybrids as drug candidates.

Design, syntheses, theoretical calculations, MM-GBSA, potential anti-cancer and enzyme activities of novel Schiff base compounds

In this study, new Schiff base compounds (SB-F-OH, SB-Cl-OH and SB-Br-OH) were derived from chalcone-derived amine compounds containing halogen groups and 4-hydroxybenzaldehyde. Also, their phthalonitrile compounds (SB-F-CN, SB-Cl-CN and SB-Br-CN) have been synthesized. The structures of these compounds were elucidated by NMR, FT-IR and Mass spectroscopic methods. The quantum chemical parameters were calculated at B3LYP/6-31++g(d,p), HF/6-31++g(d,p) and M062X/6-31++g(d,p) levels. As the biological application of the synthesized compounds, (i) their inhibition properties of the synthesized compounds on Acetylcholinesterase (AChE) and Butyrylcholinesterase (BChE) metabolic enzymes were investigated, and their potential anticancer activities against neuroblastoma (NB; SH-SY5Y) and healthy fibroblast (NIH-3T3) cell lines were determined by in vitro assays. All compounds showed inhibition at nanomolar level with the Ki values in the range of 97.86 ± 30.51-516.82 ± 31.42 nM for AChE, 33.21 ± 4.45-78.50 ± 8.91 nM for BChE, respectively. It has been determined that all tested compounds have a remarkable cytotoxic effect against SH-SY5Y, and IC50 values were significantly lower than NIH-3T3 cells. The lowest IC50 value was observed in SB-Cl-OH (7.48 ± 0.86 µM) and SB-Cl-CN (7.31 ± 0.69 µM). The molecular docking of the molecules was also investigated using crystal structure of AChE enzyme protein (PDB ID: 4M0E), crystal structure of BChE protein (PDB ID: 6R6V) and SH-SY5Y cancer protein (PDB ID: 2F3F, 3PBL and 5WIV). The ADME properties of the compounds were investigated. MM/GBSA method is calculated binding free energy. Afterwards, ADME/T analysis was performed to examine the some properties of the molecules.Communicated by Ramaswamy H. Sarma.

Exploiting butyrylcholinesterase inhibitors through a combined 3-D pharmacophore modeling, QSAR, molecular docking, and molecular dynamics investigation†

Alzheimer's disease (AD), a neurodegenerative condition associated with ageing, can occur. AD gradually impairs memory and cognitive function, which leads to abnormal behavior, incapacity, and reliance. By 2050, there will likely be 100 million cases of AD in the world's population. Acetylcholinesterase (AChE) and butyrylcholinesterase (BuChE) inhibition are significant components of AD treatment. This work developed models using the genetic method multiple linear regression, atom-based, field-based, and 3-D pharmacophore modelling. Due to internal and external validation, all of the models have solid statistical (R² > 0.81 and Q² > 0.77) underpinnings. From a pre-plated CNS library (6055), we discovered a hit compound using virtual screening on a QSAR model. Through molecular docking, additional hit compounds were investigated (XP mode). Finally, a molecular dynamics simulation revealed that the Molecule5093-4BDS complex was stable (100 ns). Finally, the expected ADME properties for the hit compounds (Molecule5093, Molecule1076, Molecule4412, Molecule1053, and Molecule3344) were found. According to the results of our investigation and the prospective hit compounds, BuChE inhibitors may be used as a treatment for AD.

Alzheimer's disease (AD), a neurodegenerative condition associated with ageing, can occur.

Synthesis and greener pastures biological study of bis-thiadiazoles as potential Covid-19 drug candidates

A novel series of bis- (Abdelhamid et al., 2017, Banerjee et al., 2018, Bharanidharan et al., 2022)thiadiazoles was synthesized from the reaction of precursor dimethyl 2,2'-(1,2-diphenylethane-1,2-diylidene)-bis(hydrazine-1-carbodithioate) and hydrazonyl chlorides in ethanol under ultrasonic irradiation. Spectral tools (IR. NMR, MS, elemental analyses, molecular dynamic simulation, DFT and LUMO and HOMO) were used to elucidate the structure of the isolated products. Molecular docking for the precursor, 3 and ligands 6a-i to two COVID-19 important proteins M^pro and RdRp was compared with two approved drugs, Remdesivir and Ivermectin. The binding affinity varied between the ligands and the drugs. The highest recorded binding affinity of 6c with M^pro was (-9.2 kcal/mol), followed by 6b and 6a, (-8.9 and -8.5 kcal/mol), respectively. The lowest recorded binding affinity was (-7.0 kcal/mol) for 6 g. In comparison, the approved drugs showed binding affinity (-7.4 and -7.7 kcal/mol), for Remdesivir and Ivermectin, respectively, which are within the range of the binding affinity of our ligands. The binding affinity of the approved drug Ivermectin against RdRp recoded the highest (-8.6 kcal/mol), followed by 6a, 6 h, and 6i are the same have (-8.2 kcal/mol). The lowest reading was found for compound 3 ligand (-6.3 kcal/mol). On the other side, the amino acids also differed between the compounds studied in this project for both the viral proteins. The ligand 6a forms three H-bonds with Thr 319(A), Sr 255(A) and Arg 457(A), whereas Ivermectin forms three H-bonds with His 41(A), Gly143(A) and Gln 18(A) for viral M^pro. The RdRp amino acids residues could be divided into four groups based on the amino acids that interact with hydrogen or hydrophobic interactions. The first group contained 6d, 6b, 6 g, and Remdesivir with 1-4 hydrogen bonds and hydrophobic interactions 1 to 10. Group 2 is 6a and 6f exhibited 1 and 3 hydrogen bonds and 15 and 14 hydrophobic interactions. Group 3 has 6e and Ivermectin shows 4 and 3 hydrogen bonds, respectively and 11 hydrophobic interactions for both compounds. The last group contains ligands 3, 6c, 6 h, and 6i gave 1-3 hydrogen bonds and 6c and 3 recorded the highest number of hydrophobic interactions, 14 for both 6c and 6 h. Pro Tox-II estimated compounds' activities as Hepatoxic, Carcinogenic and Mutagenic, revealing that 6f-h were inactive in all five similar to that found with Remdesivir and Ivermectin. The drug-likeness prediction was carried out by studying physicochemical properties, lipophilicity, size, polarity, insolubility, unsaturation, and flexibility. Generally, some properties of the ligands were comparable to that of the standards used in this study, Remdesivir and Ivermectin.

Synthesis, characterization, molecular docking, dynamics simulations, and in silico absorption, distribution, metabolism, and excretion (ADME) studies of new thiazolylhydrazone derivatives as butyrylcholinesterase inhibitors

In this study, two novel series of thiazolylhydrazone derivatives containing 4-ethylpiperazine (3a–3f) and 4-methoxyphenylpiperazine (3g–3l) side chains were synthesized and their structures were characterized by spectral (1H NMR, 13C NMR, and MS spectra) analyses. In vitro inhibitory activities of synthesized compounds against acetylcholinesterase (AChE) and butyrylcholinesterase (BChE) were determined by Ellman method. According to the results, all compounds showed a weak inhibitory effect on AChE, while promising results were obtained on BChE. Among the synthesized compounds, the activities of the derivatives carrying 4-ethylpiperazine (3a–3f) structure were found to be more effective than the compounds carrying 4-methoxyphenyl piperazine (3g–3l) derivatives. Especially, compound 3f bearing the nitro substituent was found to be the most promising compound on BChE in the series. The absorption, distribution, metabolism, and excretion (ADME) parameters of the synthesized compounds were predicted by using the SwissADME server. The potential binding mode and stability of compound 3f with BChE were investigated by the molecular docking and dynamics simulations. The results showed that 3f was strongly bound up with BChE with the optimal conformation; in addition, their binding free energy reached −167.936 ± 13.109 kJ/mol.