Synthesis, spectroscopic characterization, reactive properties by DFT calculations, molecular dynamics simulations and biological evaluation of Schiff bases tethered 1,2,4-triazole and pyrazole rings

Exploring the Potential Biological Activities of Pyrazole-Based Schiff Bases as Anti-Diabetic, Anti-Alzheimer's, Anti-Inflammatory, and Cytotoxic Agents: In Vitro Studies with Computational Predictions

In this innovative research, we aim to reveal pyrazole-based Schiff bases as new multi-target agents. In this context, we re-synthesized three sets of pyrazole-based Schiff bases, 5a-f, 6a-f, and 7a-f, to evaluate their biological applications. The data from in vitro biological assays (including antioxidant and scavenging activities, anti-diabetes, anti-Alzheimer's, and anti-inflammatory properties) of the pyrazole-based Schiff bases 5a-f, 6a-f, and 7a-f showed that the six pyrazole-based Schiff bases 5a, 5d, 5e, 5f, 7a, and 7f possess the highest biological properties among the compounds evaluated. The cytotoxicity against lung (A549) and colon (Caco-2) human cancer types, as well as normal lung (WI-38) cell lines, was evaluated. The data from the cytotoxicity investigation demonstrated that the three Schiff bases 5d, 5e, and 7a are active against lung (A549) cells, while the two Schiff bases 5e and 7a exhibited the highest cytotoxicity towards colon (Caco-2) cells. Additionally, the enzymatic activities against caspase-3 and Bcl-2 of the six pyrazole-based Schiff bases 5a, 5d, 5e, 5f, 7a, and 7f were evaluated. Furthermore, we assessed the in silico absorption, distribution, metabolism, and toxicity (ADMT) properties of the more potent pyrazole-based Schiff bases. After modifying the structures of the six pyrazole-based Schiff bases, we plan to further extend the studies in the future.

Synthesis, structural characterizations, in vitro biological evaluation and computational investigations of pyrazole derivatives as potential antidiabetic and antioxidant agents

In this study, a two pyrazole derivatives; 2-(5-methyl-1H-pyrazole-3-carbonyl)-N-phenylhydrazine-1-carboxamide (Pyz-1) and 4-amino-5-(5-methyl-1H-pyrazol-3-yl)-4H-1,2,4-triazole-3-thiol (Pyz-2) were synthesized and characterized by 13C-NMR, 1H-NMR, FT-IR, and mass spectrometry. A complete molecular structures optimization, electronic and thermodynamic properties of Pyz-1 and Pyz-2 in gas phase and aqueous solution were predicted by using hybrid B3LYP method with the 6-311++G** basis sets. Pyz-1 and Pyz-2 were evaluated in vitro for their anti-diabetic, antioxidant and xanthine oxidase inhibition activities. For anti-diabetic activity, Pyz-1 and Pyz-2 showed a potent α-glucosidase and α-amylase inhibition with IC50 values of 75.62 ± 0.56, 95.85 ± 0.92 and 119.3 ± 0.75, 120.2 ± 0.68 µM, respectively, compared to Acarbose (IC50(α-glucosidase) = 72.58 ± 0.68 µM, IC50(α-amylase) = 115.6 ± 0.574 µM). In xanthine oxidase assay, Pyz-1 and Pyz-2 exhibited remarkable inhibitory ability with IC50 values 24.32 ± 0.78 and 10.75 ± 0.54 µM, respectively. The result of antioxidant activities showed that the title compounds have considerable antioxidant and radical scavenger abilities. In addition, molecular docking simulation was used to determine the binding modes and energies between the title compounds and α-glucosidase and α-amylase enzymes.

Targeting EGFR, RSK1, RAF1, PARP2 and LIN28B for several cancer type therapies with newly synthesized pyrazole derivatives via a computational study

Cancer remains the leading cause of death in the world despite the significant advancements made in anticancer drug discovery. This study is aimed to computationally evaluate the efficacy of 63 in-house synthesized pyrazole derivatives targeted to bind with prominent cancer targets namely EGFR, RSK1, RAF1, PARP2 and LIN28B known to be expressed, respectively, in lung, colon, skin, ovarian and pancreatic cancer cells. Initially, we perform the molecular docking investigations for all pyrazole compounds with a comparison to known standard drugs for each target. Docking studies have revealed that some pyrazole compounds possess better binding affinity scores than standard drug compounds. Thereafter, a long-range of 1 μs molecular dynamic (MD) simulation study for top ranked docked compounds with all respective proteins was carried out to assess the interaction stability in a dynamic environment. The results suggested that the top ranked complexes showed a stable interaction profile for a longer period of time. The outcome of this study suggests that pyrazole compounds, M33, M36, M76 and M77, are promising molecular candidates that can modulate the studied target proteins significantly in comparison to their known inhibitor based on their selective binding interactions profile. Furthermore, ADME-T profile has been explored to check for the drug-likeness and pharmacokinetics profiles and found that all proposed compounds exhibited acceptable values for being a potential drug-like candidate with non-toxic characteristics. Overall, extensive computational investigations indicate that the four proposed pyrazole inhibitors/modulators studied against each respective target protein will be helpful for future cancer therapeutic developments.Communicated by Ramaswamy H. Sarma.

Biological, toxicological and molecular docking evaluations of isoxazoline-thiazolidine-2,4-dione analogues as new class of anti-hyperglycemic agents

In this work, three isoxazoline-thiazolidine-2,4-dione derivatives were synthesized and characterized by FT-IR, ¹H-NMR, ¹³C-NMR and ESI-MS spectrometry. All compounds have been investigated for their α-amylase and α-glucosidase inhibitory activities. In vitro enzymatic evaluation revealed that all compounds were inhibitory potent against α-glucosidase with IC₅₀ values varied from 40.67 ± 1.81 to 92.54 ± 0.43 µM, and α-amylase with IC₅₀ in the range of 07.01 ± 0.02 to 75.10 ± 1.06 µM. One of the tested compounds were found to be more potent inhibitor compared to other compounds and standard drug Acarbose (IC_{50 glucosidase}= 97.12 ± 0.35 µM and IC_{50 amylase}= 2.97 ± 0.01 μM). All compounds were then evaluated for their acute toxicity in vivo and shown their safety at a high dose with LD > 2000mg/kg BW. A cell-based toxicity evaluation was performed to determine the safety of compounds on liver cells, using the MTT assay against HepG2 cells, and the results shown that all compounds have non-toxic impact against cell viability and proliferation compared to reference drug (Pioglitazone). Furthermore, the molecular homology analysis, SAR and the molecular binding properties of compound with the active site of α-amylase and α-glucosidase were confirmed through computational analysis. This study has identified the inhibitory potential of a new class of synthesized isoxazoline-thiazolidine-2,4-dione derivatives in controlling both hyperglycemia and type 2 diabetes mellitus without any hepatic toxicity.Communicated by Ramaswamy H. Sarma.

Synthesis, crystal structure, DFT, Hirshfeld surface analysis, energy framework, docking and molecular dynamic simulations of (E)-4-(4-methylbenzyl)-6-styrylpyridazin-3(2H)-one as anticancer agent

In this work, a novel crystal, (E)-4-(4-methylbenzyl)-6-styrylpyridazin-3(2H)-one (E-BSP) was synthesized via Knoevenagel condensation of benzaldehyde and (E)-6-(4-methoxystyryl)-4,5-dihydropyridazin-3(2H)-one. The molecular structure of E-BSP was confirmed by using FT-IR, 1H-NMR, 13C-NMR, UV-vis, ESI-MS, TGA/DTA thermal analyses and single crystal X-ray diffraction. The DFT/B3LYP methods with the 6-311++G(d,p) basis set were used to determine the vibrational modes over the optimized structure. Potential energy distribution (PED) and the VEDA 4 software were used to establish the theoretical mode assignments. The same approach was used to compute the energies of frontier molecular orbitals (HOMO-LUMO), global reactivity descriptors, and molecular electrostatic potential (MEP). Additionally, experimental and computed UV spectral parameters were determined in methanol and the obtained outputs were supported by FMO analysis. Molecular docking and molecular dynamics (MD) simulation analyses of the E-BSP against six proteins obtained from different cancer pathways were carried out. The proteins include; epidermal growth factor receptor (EGFR), Estrogen receptor (ERα), Mammalian target of rapamycin (mTOR), Progesterone receptor (PR) (Breast cancer), Human cyclin-dependent kinase 2 (CDK2) (Colorectal cancer), and Survivin (Squamous cell carcinoma/Non-small cell lung cancer). The results of the analyses showed that the compound had less binding energies ranging between -6.30 to -9.09 kcal/mol and formed stable complexes at the substrate-binding site of the proteins after the 50 ns MD simulation. Therefore, E-BSP was considered a potential inhibitor of different cancer pathways and should be used for the treatment of cancer after experimental validation and clinical trial.Communicated by Ramaswamy H. Sarma.

Pyrazole scaffold-based derivatives: A glimpse of α-glucosidase inhibitory activity, SAR, and route of synthesis

The α-glucosidase is a validated target to develop drugs for treating type 2 diabetes mellitus. The existing α-glucosidase inhibitors have certain shortcomings related to side effects and route of synthesis. Accordingly, it is inevitable to develop new chemical templates as α-glucosidase inhibitors. Pyrazole derivatives have a special place in medicinal chemistry because of various biological activities. Recently, pyrazole-based heterocyclic compounds have emerged as a promising scaffold to develop α-glucosidase inhibitors. This study focuses on the recently reported pyrazole-based α-glucosidase inhibitors, including their biological activity (in vivo, in vitro, and in silico), structure-activity relationship, and ways of synthesis. The literature revealed the development of several promising pyrazole-based α-glucosidase inhibitors and new synthetic routes for their preparation. The encouraging α-glucosidase inhibitory results of the pyrazole-based heterocyclic compounds make them an attractive target for further research. The authors also foresee the arrival of the pyrazole-based α-glucosidase inhibitors in clinical practice.

Synthesis, crystal structure, Hirshfeld surface analysis, energy frameworks and computational studies of Schiff base derivative

The compound (E)-ethyl 3-(2-(2,4-dinitrophenyl)hydrazono)butanoate (3) was synthesised and crystallized using ethanol as a solvent. The compound was characterized by ¹H NMR, and single crystal X-ray diffraction. The compound crystallizes in the monoclinic crystal system with the space group P2₁/c. The intermolecular interactions and the interaction energies responsible for the stabilization of the molecules were determined by Hirshfeld surface analysis and energy framework calculations. The structure of the compound was optimized by Density Functional Theory calculations and HOMO–LUMO energy gap was calculated. The non–covalent interactions were revealed by reduced density gradient analysis. The Mulliken atomic charges and natural atomic charges were calculated by density functional theory calculations. The reactive sites present in the molecule are shown by molecular electrostatic potential map. The inter and intra molecular charge transfer were investigated by NBO analysis.

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Crystal structure was confirmed by X-ray diffraction analysis and the atomic coordinates were optimized by DFT calculations.

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Hirshfeld surface analysis and energy frameworks calculations were carried out.

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HOMO - LUMO frontier molecular orbitals and molecular electrostatic potential were studied.

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Reduced density gradient (RDG), and topology analyses were performed.

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Natural bond orbital analysis was performed to study intramolecular charge transfer.

Combined Experimental and Computational Study on the Transformation of a Novel 1,3,4-Oxadiazole Thioether Nematicide in Aqueous Solutions

It has been demonstrated that Exianliuyimi (EXLYM) exhibits good nematocidal activity. As a potential nematicide, EXLYM and its transformation products (TPs) may generate emerging pollutants with hazardous effects on the ecosystem. In this study, the fate of EXLYM in aqueous solutions was investigated using experimental and theoretical approaches. Laboratory-scale experiments showed that EXLYM is hydrolytically stable. Microbial processes are primarily responsible for the oxidation of sulfur in aqueous solutions. Under simulated sunlight, the t_1/2 values of EXLYM in acidic, neutral, and alkaline buffer solutions were 5.02, 3.83, and 5.55 h, respectively. Six TPs were identified using a non-target screening strategy realized by ultra-high-performance liquid chromatography coupled with Q-Exactive Orbitrap high-resolution mass spectrometry and ¹⁸O-labeling experiments. Four of these were unambiguously confirmed using authentic standards. Reactive oxygen species scavenging experiments, ¹⁸O-labeling experiments, and quantum-theoretical calculations suggested that EXLYM could degrade mainly through four pathways: sulfur oxidation, nucleophilic aromatic photosubstitution, C-S bond cleavage, and oxidative ring-opening. The proposed degradation kinetics, TPs, and transformation pathways in aqueous solutions provide valuable information on the fate of EXLYM in aquatic ecosystems and lay the foundation for further toxicological tests.

Design and prediction of novel pyrazole derivatives as potential anti-cancer compounds based on 2D-2D-QSAR study against PC-3, B16F10, K562, MDA-MB-231, A2780, ACHN and NUGC cancer cell lines

Despite the decades of scientific studies for developing promising new therapies, cancer remains a major cause of illness and mortality, worldwide. Several cancer types are the major topic of research in drug discovery programs due to their global incidence cases and growing frequency. In the present study, using two different statistical approaches PCA (principal component analysis) and PLS (partial least squares), six 2D-QSAR (quantitative structure activity relationship) models have been developed for the set of compounds retrieved against seven cancer cell lines vizPC-3, B16F10, K562, MDA-MB-231, A2780, and ACHN. For the creation and validation of 2D-QSAR models, OECD (Organization for Economic Co-operation and Development) requirements have been strictly followed. All of the generated 2D-QSAR models produce a significant and high correlation coefficient value with several other statistical parameters. Moreover, developed 2D-QSAR models have been used for activity predictions of in-house synthesized 63 pyrazole derivatives compounds. Precisely, most statistically significant and accepted2D-QSAR model generated for each cancer cell line has been used to predict the pIC₅₀ value (anti-cancer activity) of all 63 synthesized pyrazole derivatives. Furthermore, designing of novel pyrazole derivatives has been carried out by substituting the essential functional groups based on the best derived 2D-QSAR models for each cancer cell line, more precisely, based on the most significant molecular descriptors with enhanced anti-cancer activity. Finally, the prediction of the new designed molecules reveals higher pIC₅₀ than the standard compounds.

Fabrication, depiction, DNA interaction, anti-bacterial, DFT and molecular docking studies of Co(II) and Cu(II) complexes of 3-methyl-1-phenyl-4-[(E)-(pyridin-2-yl)diazenyl]-1H-pyrazol-5-ol ligand

Cobalt(II) and copper(II) complexes of the (3-methyl-1-phenyl-4-[E-(1iazinyl-2-yl)1iazinyl]-1H-pyrazole-5-ol) ligand were obtained by the diazotization reaction of 5-methyl-2-phenyl-2,4-dihydro-3H-pyrazol-3-one with 2-amino pyridine. The synthesized compounds were confirmed by analytical, and spectroscopic analyses (like, UV-Visible, FT-IR, NMR, and mass spectroscopy). Calf thymus DNA interaction with metal complexes is inspected by UV-Visible spectra, viscosity measurements, and thermal denaturation techniques. The intrinsic binding constant (K_b) was found to be 1.17 × 10⁶ M^-1, and 0.98 × 10⁶ M^-1 for Co(II) and Cu(II) complexes respectively. The Cleavage of pUC-19 DNA was monitored by gel electrophoresis. The computerized in silico molecular dockage studies of the composites with the target receptor Glu-6p and results showed that the compounds are potent drugs for the target enzyme. Further, the optimized structure of the azo dye ligand was obtained by the density functional theory (DFT) by Gaussian09 program by the RB3LYP at 6-311 G (++, g, d, p) basis set. Furthermore, screened for the bacterial action in contradiction of pathogenic organism's gram-negative Klebsiella pneumonia, gram-positive Bacillus subtills by a diffusion method.Supplemental data for this article is available online at https://doi.org/10.1080/15257770.2021.1991373 .

Investigation of Pharmaceutical Importance of 2H-Pyran-2-One Analogues via Computational Approaches

Highly functionalized spirocyclic ketals were synthesized through asymmetric oxidative spirocyclization via carbanion-induced ring transformation of 2H-pyran-2-ones with 1,4-cyclohexandione monoethyleneketal under alkaline conditions. Further acidic-hydrolysis of obtained spirocyclic ketals yields highly substituted 2-tetralone in good yield. Computational analysis based on the DFT calculations and MD simulations has been performed in order to predict and understand global and local reactivity properties of newly synthesized derivatives. DFT calculations covered fundamental reactivity descriptors such as molecular electrostatic potential and average local ionization energies. Nitrogen atom and benzene rings have been recognized as the most important molecular sites from these aspects. Additionally, to predict whether studied compounds are stable towards the autoxidation mechanism, we have also studied the bond dissociation energies for hydrogen abstraction and identified the derivative which might form potentially genotoxic impurities. Interactions with water, including both global and local aspects, have been covered thanks to the MD simulations and calculations of interaction energies with water, counting of formed hydrogen interactions, and radial distribution functions. MD simulations were also used to identify which excipient could be used together with these compounds, and it has been established that the polyvinylpyrrolidone polymer could be highly compatible with these compounds, from the aspect of calculated solubility parameters.

Antiviral Activity of Isoimperatorin Against Influenza A Virus in vitro and its Inhibition of Neuraminidase

Influenza A virus (IAV) poses a severe threat to human health and is a major public health problem worldwide. As global anti-influenza virus drug resistance has increased significantly, there is an urgent need to develop new antiviral drugs, especially drugs from natural products. Isoimperatorin, an active natural furanocoumarin, exhibits a broad range of pharmacologic activities including anticoagulant, analgesic, anti-inflammatory, antibacterial, anti-tumor, and other pharmacological effects, so it has attracted more and more attention. In this study, the antiviral and mechanistic effects of isoimperatorin on influenza A virus in vitro were studied. Isoimperatorin illustrated a broad-spectrum antiviral effect, especially against the A/FM/1/47 (H1N1), A/WSN/33 (H1N1, S31N, amantadine resistant), A/Puerto Rico/8/34 (H1N1), and A/Chicken/Guangdong/1996 (H9N2) virus strains. The experimental results of different administration modes showed that isoimperatorin had the best antiviral activity under the treatment mode. Further time-of-addition experiment results indicated that when isoimperatorin was added at the later stage of the virus replication cycle (6–8 h, 8–10 h), it exhibited an effective antiviral effect, and the virus yield was reduced by 81.4 and 84.6%, respectively. In addition, isoimperatorin had no effect on the expression of the three viral RNAs (mRNA, vRNA, and cRNA). Both the neuraminidase (NA) inhibition assay and CETSA demonstrated that isoimperatorin exerts an inhibitory effect on NA-mediated progeny virus release. The molecular docking experiment simulated the direct interaction between isoimperatorin and NA protein amino acid residues. In summary, isoimperatorin can be used as a potential agent for the prevention and treatment of influenza A virus.

Synthesis, α-glucosidase and α-amylase inhibitory activities, acute toxicity and molecular docking studies of thiazolidine-2,4-diones derivatives

In the present study, a series of thiazolidine-2,4-diones derivatives (3a-3e) and (4a-4e) were synthesized and characterized by ¹H NMR, ¹³C NMR and ESI-MS spectrometry. All compounds were screened for their α-glucosidase and α-amylase inhibitory activities. In vitro biological investigations revealed that most of compounds were active against α-glucosidase with IC₅₀ values in the range of 43.85 ± 1.06 to 380.10 ± 1.02 µM, and α-amylase with IC₅₀ in the range of 18.19 ± 0.11 to 208.10 ± 1.80 µM. Some of the tested compounds were found to be more potent inhibitors than the clinical drug Acarbose (IC_{50glucosidase} = 97.12 ± 0.35 µM and IC_50amylase = 2.97 ± 0.004 μM). The lead compounds were evaluated for their acute toxicity on Swiss mice and found to be completely non-toxic with LD > 2000 mg/kg BW. Furthermore, the Structure-activity relationship (SAR) and the binding interactions of all compounds with the active site of α-glucosidase and α-amylase were confirmed through molecular docking and stabilizing energy calculations. This study has identified the inhibitory potential a new class of synthesized thiazolidine-2,4-diones in controlling both hyperglycemia and type 2 diabetes mellitus. Furthermore, the theoretical binding mode of the target molecules was evaluated by molecular docking studies against the 3D Crystal Structure of human pancreatic α-amylase (PDB ID: 1B2Y) and α-glucosidase (PDB ID: 3W37)Communicated by Ramaswamy H. Sarma.

Antioxidant Activity of 1,2,4-Triazole and Its Derivatives: A Mini Review

The information about the presence of free radicals in biological materials was given for the first time about 70 years ago. Since then, numerous scientific studies have been conducted and the science of free radicals was born. Today we know that free radicals are by-products of enzymatic reactions occurring in the organism. They are produced during endogenous processes such as: cell respiration, phagocytosis, biosynthesis, catalysis, and biotransformation. They can also be produced by exogenous processes (radiation, sunlight, heavy metals, bacteria, fungi, protozoa and viruses). The overproduction of free radicals affects the aging processes, oxidative stress (OS) and takes part in the pathogenesis of various diseases. Among them are cancer, rheumatoid arthritis, neurodegenerative diseases: Alzheimer and Parkinson, pulmonary diseases, atherosclerosis and DNA damage. Compounds with antioxidant activity are very important nowadays because they allow organisms to keep a balance between the production of free radicals and the speed of their neutralization in the body. Next to the natural antioxidants (flavonoids, carotenoids, vitamins, etc.), synthetic ones are also of great importance. Among synthetic compounds with antioxidant activity are 1,2,4-triazoles and its derivatives. 1,2,4-Triazoles are heterocyclic compounds with three nitrogen atoms. Due to a broad spectrum of biological activities, these derivatives have been of interest to scientists for many years. Some of them are also used as drugs. The finding of new synthetic compounds with antioxidant features in the triazole group has become important problem of medicinal chemistry.

Chalcones and Bis-Chalcones Analogs as DPPH and ABTS Radical Scavengers

Background:

A number of synthetic scaffolds, along with natural products, have been identified as potent antioxidants. The present study deals with the evaluation of varyingly substituted, medicinally distinct class of compounds “chalcones and bis-chalcones” for their antioxidant potential.

Methods:

In vitro radical scavenging activities were performed on a series of synthetic chalcones 1- 13 and bis-chalcones 14-18.

Results:

All molecules 1-18 revealed a pronounced 2-diphenyl-1-picrylhydrazyl (DPPH) and 2,2ʹ- azino-bis(3-ethylbenzothiazoline-6-sulphonic acid) (ABTS) radicals scavenging potential in the ranges of IC50s = 0.58 ± 0.14 - 1.72 ± 0.03 and 0.49 ± 0.3 - 1.48 ± 0.06 μM, respectively. Ascorbic acid (IC50s = 0.5 ± 0.1 and 0.46 ± 0.17 μM for DPPH and ABTS, respectively) was used as a standard radical scavenger.

Conclusion:

Structure-activity relationship (SAR) revealed an active participation of various groups, including -SMe and -OMe in scavenging activity.

Synthesis, spectroscopy, crystal structure, TGA/DTA study, DFT and molecular docking investigations of (E)-4-(4-methylbenzyl)-6-styrylpyridazin-3(2H)-one

In this study, we present the synthesis of novel pyridazin-3(2H)-one derivative namely (E)-4-(4-methylbenzyl)-6-styrylpyridazin-3(2H)-one (MBSP). The chemical structure of MBSP was characterized using spectroscopic techniques such as FT-IR, ¹H NMR, ¹³C NMR, UV-Vis, ESI-MS, and finally, the structure was confirmed by single X-ray diffraction studies. The DFT calculation was performed to compare the gas-phase geometry of the title compound to the solid-phase structure of the title compound. Furthermore, a comparative study between theoretical UV-Vis, IR, ¹H- and ¹³C NMR spectra of the studied compound and experimental ones have been carried out. The thermal behavior and stability of the compound were analyzed by using TGA and DTA techniques which revealed that the compound is thermostable up to its melting point. Finally, the in silico docking and ADME studies are performed to investigate whether MBSP is a potential therapeutic for COVID-19.

Synthesis, cytotoxicity of some pyrazoles and pyrazolo[1,5-a]pyrimidines bearing benzothiazole moiety and investigation of their mechanism of action

A novel series of pyrazoles and pyrazolo[1,5-a]pyrimidines bearing benzothiazole moiety were designed and synthesized. Chemical structures were confirmed by spectral data and elemental analyses. Nine compounds were selected and screened for their cytotoxic activity at the National Cancer Institute (NCI), USA against 60 cancer cell lines in a single dose assay. Compounds 4 and 5 exerted the most potent growth inhibitory activity against most cancer cell lines with growth inhibition (GI%) ranges from 44.86% to 84.59% and 31.20% to 52.36%, respectively. Consequently, they were further investigated through IC₅₀ determination using five dose MTT colorimetric assay against three sensitive cell lines, leukemia CCRF-CEM, non-small cell lung cancer HOP-92 and liver cancer Hep-G2. Compound 4 exhibited potent cytotoxic activity against the three tested cell lines with IC₅₀ 16.34, 3.45 and 7.79 μM, respectively representing half potency, 3.5 folds potency and nearly equipotent to roscovitine. To investigate its mechanism of action, cell cycle analysis of compound 4 was conducted and showed that it induced cell cycle arrest at G2/M phase and apoptosis in HOP-92 cells. In correlation with the previous results, caspase-3 activation was tested and illustrated elevation in its concentration by nearly 14 folds than control. Besides, enzyme inhibition assay of compound 4 was evaluated towards two common antitumor targets namely KDM1 and CDK1 showing significant inhibitory activity with IC₅₀ 0.096 and 0.078 μM, respectively.

An Overview of Coumarin as a Versatile and Readily Accessible Scaffold with Broad-Ranging Biological Activities

Privileged structures have been widely used as an effective template for the research and discovery of high value chemicals. Coumarin is a simple scaffold widespread in Nature and it can be found in a considerable number of plants as well as in some fungi and bacteria. In the last years, these natural compounds have been gaining an increasing attention from the scientific community for their wide range of biological activities, mainly due to their ability to interact with diverse enzymes and receptors in living organisms. In addition, coumarin nucleus has proved to be easily synthetized and decorated, giving the possibility of designing new coumarin-based compounds and investigating their potential in the treatment of various diseases. The versatility of coumarin scaffold finds applications not only in medicinal chemistry but also in the agrochemical field as well as in the cosmetic and fragrances industry. This review is intended to be a critical overview on coumarins, comprehensive of natural sources, metabolites, biological evaluations and synthetic approaches.

Crystal structure of (E)-1-(2-nitrophenyl)-N-(o-tolyl)methanimine, C14H12N2O2

C14H12N2O2, monoclinic, P21, a = 8.3844(1) Å, b = 20.0465(3) Å, c = 14.0511(2) Å, β = 94.786(1)°, V = 2353.44(6) Å3, Z = 4, R gt(F) = 0.0356, wR ref(F 2) = 0.1022, T = 150(2) K.

Discovery of New Schiff Bases Tethered Pyrazole Moiety: Design, Synthesis, Biological Evaluation, and Molecular Docking Study as Dual Targeting DHFR/DNA Gyrase Inhibitors with Immunomodulatory Activity

A series of Bis-pyrazole Schiff bases (6a–d and 7a–d) and mono-pyrazole Schiff bases (8a–d and 9a–d) were designed and synthesized through the reaction of 5-aminopyrazoles 1a–d with aldehydes 2–5 using mild reaction condition with a good yield percentage. The chemical structure of newly formed Schiff bases tethered pyrazole core was confirmed based on spectral and experimental data. All the newly formed pyrazole Schiff bases were evaluated against eight pathogens (Gram-positive, Gram-negative, and fungi). The result exhibited that, most of them have good and broad activities. Among those, only six Schiff bases (6b, 7b, 7c, 8a, 8d, and 9b) displayed MIC values (0.97–62.5 µg/mL) compared to Tetracycline (15.62–62.5 µg/mL) and Amphotericin B (15.62–31.25 µg/mL), MBC values (1.94–87.5 µg/mL) and selectivity to tumor cell than normal cells. Immunomodulatory activities showed that the promising Schiff bases increase the immunomodulator effect of defense cell and the Schiff base 8a is the highest one by (Intra. killing activity = 136.5 ± 0.3%) having a pyrazole moiety as well as amide function (O=C-NH₂) and piperidinyl core. Furthermore, the most potent one exhibited broad activity depending on both MIC and MBC values. Moreover, to study the mechanism of these pyrazole Schiff bases, two active Schiff bases 8a and 9b from six derivatives were introduced to study the enzyme assay as dihydrofolate reductase (DHFR) on E. coli organism and DNA gyrase with two different organisms, S. aureus and B. subtilis, to determine the inhibitory activities with lower values in the case of DNA gyrase (8a and 9b) or nearly as DHFR compound 9b, while pyrazole 8a showed excellent inhibitory against all enzyme assay. The molecular docking study against dihydrofolate reductase and DNA gyrase were performed to study the binding between active site in the pocket with the two Schiff bases (8a and 9b) that exhibited good binding affinity with different bond types as H-bonding, aren-aren, and arene-cation interaction as well as study the physicochemical and pharmacokinetic properties of the two active Schiff bases 8a and 9b.