Hydroxyphenylamine phosphonate derivatives: Synthesis, X-ray crystallographic analysis, and evaluation of theirs anti-Alzheimer effects and antioxidant activities

Synthesis, DFT Calculations, and Biological Studies of New 2-Cyano-3-(Naphthalene-1-yl) Acryloyl Amide Analogues as Anticancer Agents

A set of novel naphthalene derivatives was synthesized via investment of the electrophilic reaction center of the easily obtainable starting substance, 2-cyano-3-(naphthalen-1-yl)acryloyl chloride (1), with various nitrogen nucleophiles and assessed as potential antitumor agents. The chemical structures of these derivatives were completely specified using several spectral and elemental analyses. The antiproliferative efficacy of the discovered compounds against the human cancer cell lines HepG2 and MCF-7 was investigated. Compounds 12b and 9 have more potent anticancer activity versus MCF-7 breast cancer. DFT calculations for the synthesized compounds were studied to determine molecular geometry, frontier orbital analysis, and molecular electrostatic potential. Compound 2 has the lowest energy gap, the highest softness, and the lowest hardness molecule. Also, the electrophilicity values of the studied molecules provide evidence for their biological effectiveness, as compound 9 had significant antiproliferative activity and a high value of electrophilicity (ω) (0.190 eV).

Inhibition of cytotoxic self-assembly of HEWL through promoting fibrillation by new synthesized α-hydroxycarbamoylphosphinic acids

The main objective of the present study is to investigate the potency of new synthesized hydroxycarbamoyl phosphinic acid derivatives in modulating cytotoxic fibrillogenesis of hen egg white lysozyme (HEWL), as a common model in protein aggregation studies. Hydroxycarbamoyl phosphinic acid derivatives were prepared by the reaction of α-hydroxyalkylphosphinic acids with isocyanates (or isothiocyanates) in the presence of trimethylsilyl chloride (TMSCl). The designed process involves the condensation reaction leading to formation of new C sp2-P bond formation. The synthesis and purity of novel designed compounds were confirmed by NMR, LC-MS, and HPLC techniques. A range of experiments, including thioflavin T (ThT) and 8-anilino-1-naphthalenesulfonic acid (ANS) fluorescence assays, Congo red binding measurement, atomic force microscopy imaging, MTT-based cell viability and hemolysis assays were employed to investigate anti-amyloidogenic effects of tested compounds. The obtained results demonstrate that these compounds are able to significantly modulate the self-assembly process of HEWL via shortening of nucleation phase leading to the acceleration of fibrillation and appearance of very large and thick fibrils with decreased surface hydrophobicity and cytotoxicity. Based on ANS binding data, we suggest that increased exposure of hydrophobic patches of oligomeric species is the possible mechanism by which tested compounds promote self-assembly process of HEWL. Fluorescence anisotropy and molecular docking studies indicate the interaction of both synthesized compounds with HEWL, and more specifically with residues that are situated in the highly aggregation-prone β-domain region of protein. This study unveils the potential of hydroxyalkylphosphinic acids as modulators of amyloid fibrillation highlighting these compounds as a promising approach for targeting protein aggregates associated with neurodegenerative diseases.

Green approach to the synthesis of α-aminophosphonate-tetrahydroisoquinoline hybrids and their anti-cholinesterase activity

A series of 19 novel α-aminophosphonate-tetrahydroisoquinoline hybrids were synthesized through a cross dehydrogenative coupling reaction between N-aryl-tetrahydroisoquinolines and dialkylphosphites, using tert-butyl hydroperoxide as oxidazing agent. This simple procedure provided products with high atom economy and moderate to high yields. In vitro cholinesterase inhibitory activity of these compounds was evaluated. All the synthesized compounds showed good to excellent selective inhibition against butyrylcholinesterase. Compound 3bc was found to be the most active derivative with an IC50 of 9 nM. Molecular modelling studies suggested that the inhibitor is located in the peripheral anionic site (PAS) of the enzyme and interacts with some residue of the catalytic anionic site. Kinetic studies revealed that 3bc acts as a non-competitive inhibitor. Predicted ADME showed good pharmacokinetics and drug-likeness properties for most hybrids. Each newly synthesized compound was characterized by IR, 1H NMR, 13C NMR, 31P NMR spectral studies and also HRMS. The results of this study suggest that α-aminophosphonate-tetrahydroisoquinoline hybrids can be promising lead compounds in the discovery of new and improved drugs for the treatment of Alzheimer's disease and related neurodegenerative disorders.

New2-((2-(2,4-dinitrophenyl)hydrazineeylidene) derivatives: design, synthesis, in silico, and in vitro anticancer studies

A series of novel hydrazone compounds have been synthesized by the condensation of hydrazines and different substituted salicylaldehydes at a molar ratio of 1:1 in one step reaction and characterized by FT-IR, ESI-MS, 1H NMR, and single crystal x-ray diffraction. The crystal structure of the compound shows a trans configuration around the C = N bond and triclinic system with P -1/-p 1. Synthesized compounds were screened for cytotoxicity activities against A375 (melanoma), HT-29 (Colon), and A549 (lung) cancer cell lines. Among them, compound 2 exhibited the highest cytotoxic effect against the A375 cell line (IC50 = 0.30 µM) and HT-29 cell line (1.68 µM), compared to those of apatinib as a reference standard drug (0.28, 1.49 µM, respectively). The cytocompatibility assay on the L929 normal cell line and the hemolysis assay on human RBC were used to validate the non-toxic action. From DFT calculation, the various parameters such as HOMO-LUMO energies, Hirshfeld, and MEP have been studied. Furthermore, in silico molecular docking with three receptors was studied. Among four compounds, compound 2 has the lowest binding energy against cyclin dependent kinase (ΔGb = -9.3 kcal/mol). In addition to this, molecular dynamics (MD) simulation was also performed. Based on this study, these novel hydrazones can be considered a promising anticancer agent due to their potent cytotoxicity activities and computational analysis.Communicated by Ramaswamy H. Sarma.

Design, synthesis, anti-acetylcholinesterase evaluation and molecular modelling studies of novel coumarin-chalcone hybrids

The major enzyme responsible for the hydrolytic breakdown of the neurotransmitter acetylcholine (ACh) is acetylcholinesterase (AChE). Acetylcholinesterase inhibitors (AChEIs) are the most prescribed class of medications for the treatment of Alzheimer's disease (AD) and dementia. The limitations of available therapy, like side effects, drug tolerance, and inefficacy in halting disease progression, drive the need for better, more efficacious, and safer drugs. In this study, a series of fourteen novel chalcone-coumarin derivatives (8a-n) were designed, synthesized and characterized by spectral techniques like FT-IR, NMR, and HR-MS. Subsequently, the synthesized compounds were tested for their ability to inhibit acetylcholinesterase (AChE) activity by Ellman's method. All tested compounds showed AChE inhibition with IC50 value ranging from 0.201 ± 0.008 to 1.047 ± 0.043 μM. Hybrid 8d having chloro substitution on ring-B of the chalcone scaffold showed relatively better potency, with IC50 value of 0.201 ± 0.008 μM compared to other members of the series. The reference drug, galantamine, exhibited an IC50 at 1.142 ± 0.027 μM. Computational studies revealed that designed compounds bind to the peripheral anionic site (PAS), the catalytic active site (CAS), and the mid-gorge site of AChE. Putative binding modes, ligand-enzyme interactions, and stability of the best active compound are studied using molecular docking, followed by molecular dynamics (MD) simulations. The cytotoxicity of the synthesised derivatives was determined using the MTT test at three concentrations (100 g/mL, 500 g/mL, and 1 mg/mL). None of the chemicals had a significant effect on the body at the highest dose of 1 mg/mL.Communicated by Ramaswamy H. Sarma.

Synthesis, characterization, DFT, antioxidant, antibacterial, pharmacokinetics and inhibition of SARS-CoV-2 main protease of some heterocyclic hydrazones

Three hydrazone derivatives have been synthesized using condensation reaction of 4-hydrazinylbenzoic acid with three aromatic aldehydes namely: thiophene-2-carbaldehyde, thiophene-3-carbaldehyde and 2-furaldehyde in ethanol at 78 °C reflux. The synthesized molecules have been characterized using spectroscopic and physicochemical methods including UV-Vis, IR, ¹H NMR, ¹³C NMR, ¹⁵N NMR and melting point determination. Optimized molecular structures, UV-Vis and IR spectra modeling, the reactivity, the stability and some quantum chemical parameters of the synthesized molecules were modeled utilizing density functional theory (DFT). The obtained theoretical results were found in good agreement with the experimental results. On the other hand, the antioxidant and antibacterial activities of the molecules under study were evaluated to better understand the associated mechanisms of action specifically. Also, predicted ADME-T and pharmacokinetic parameters indicated that these compounds showed good oral bioavailability. Finally, molecular docking has been used to predict the inhibitory activity of the studied hydrazone derivatives on the SARS-CoV-2 main protease (Mpro).

Novel Strategy to fabricate Antiwrinkle Cotton fabrics with 1,2,3,4-Butanetetracarboxylic Acid under a Low Temperature

As a most promising formaldehyde-free crosslinking agent for the antiwrinkle treatment of cotton fabrics, 1,2,3,4-butanetetracarboxylic acid (BTCA) has been explored for many years to replace the traditional N-methylol resin. However, the current methodology for preparing antiwrinkle cotton fabrics with BTCA mainly highlights the troublesome problem of higher curing temperature. In this research, a novel strategy with the aid of dimethyl sulfone (MSM) was developed to decrease the curing temperature of BTCA for fabricating antiwrinkle cotton fabrics, which is an eco-friendly additive with low price and wonderful biocompatibility. Temperature-dependent Fourier-transform infrared spectroscopy, X-ray photoelectron spectroscopy, and computational simulations were employed to analyze the mechanism of MSM in the overall reaction between BTCA and cellulose. Based on the strong hydrogen-bond acceptor property of MSM, the noncovalent interactions in the crosslinking system could be easily interrupted, which facilitates the BTCA diffusion in amorphous regions of cellulose, anhydride formation, and the thermal vibration of cellulose chains during the processing. Physically and chemically speaking, both reactivities of grafting and crosslinking reactions of BTCA are significantly increased with the assistance of MSM, consequently reducing the curing temperature, which will hopefully help achieve the industrial-scale application of BTCA in antiwrinkle treatment.

Chemical Composition, Anti-Quorum Sensing, Enzyme Inhibitory, and Antioxidant Properties of Phenolic Extracts of Clinopodium nepeta L. Kuntze

Phenolic extracts of Clinopodium nepeta were prepared and their preliminary phenolic profiles determined using HPLC-DAD with 26 phenolic standards. Apigenin (21.75 ± 0.41 µg/g), myricetin (72.58 ± 0.57 µg/g), and rosmarinic acid (88.51 ± 0.55 µg/g) were the most abundant compounds in DCM (dichloromethane), AcOEt (ethyl acetate), and BuOH (butanol) extracts, respectively. The DCM and AcOEt extracts inhibited quorum-sensing mediated violacein production by C. violaceum CV12472. Anti-quorum-sensing zones on C. violaceum CV026 at MIC (minimal inhibitory concentration) were 10.3 ± 0.8 mm for DCM extract and 12.0 ± 0.5 mm for AcOEt extract. Extracts showed concentration-dependent inhibition of swarming motility on flagellated P. aeruginosa PA01 and at the highest test concentration of 100 μg/mL, AcOEt (35.42 ± 1.00%) extract displayed the best activity. FRAP assay indicated that the BuOH extract (A0.50 = 17.42 ± 0.25 µg/mL) was more active than standard α-tocopherol (A0.50 = 34.93 ± 2.38 µg/mL). BuOH extract was more active than other extracts except in the ABTS●+, where the DCM extract was most active. This antioxidant activity could be attributed to the phenolic compounds detected. C. nepeta extracts showed moderate inhibition on acetylcholinesterase (AChE), butyrylcholinesterase (BChE), tyrosinase, and α-amylase. The results indicate that C. nepeta is a potent source of natural antioxidants that could be used in managing microbial resistance and Alzheimer's disease.