Fabrication, spectroscopic characterization, calf thymus DNA binding investigation, antioxidant and anticancer activities of some antibiotic azomethine Cu(II), Pd(II), Zn(II) and Cr(III) complexes

Manganese(II) and Zinc(II) metal complexes of novel bidentate formamide-based Schiff base ligand: synthesis, structural characterization, antioxidant, antibacterial, and in-silico molecular docking study

A new bidentate Schiff base ligand (C16H16Cl2N4), condensation product of ethylene diamine and 4-chloro N-phenyl formamide, and its metal complexes [M(C16H16Cl2N4)2(OAc)2] (where M = Mn(II) and Zn(II)) were synthesized and characterized using various analytical and spectral techniques, including high-resolution mass spectrometry (HRMS), elemental analysis, ultraviolet-visible (UV-vis), Fourier-transform infrared (FTIR) spectroscopy, AAS, molar conductance, 1H NMR, and powder XRD. All the compounds were non-electrolytes and nanocrystalline. The synthesized compounds were assessed for antioxidant potential by DPPH radical scavenging and FRAP assay, with BHT serving as the positive control. Inhibitory concentration at 50% inhibition (IC50) values were calculated and used for comparative analysis. Furthermore, the prepared compounds were screened for antibacterial activity against two Gram-negative bacteria (Staphylococcus aureus and Bacillus subtilis) and two Gram-positive bacteria (Escherichia coli and Salmonella typhi) using disk-diffusion methods, with amikacin employed as the standard reference. The comparison of inhibition zones revealed that the complexes showed better antibacterial activity than the ligand. To gain insights into the molecular interactions underlying the antibacterial activity, the ligand and complexes were analyzed for their binding affinity with S. aureus tyrosyl-tRNA synthetase (PDB ID: 1JIL) and S. typhi cell membrane protein OmpF complex (PDB ID: 4KR4). These analyses revealed robust interactions, validating the observed antibacterial effects against the tested bacterial strains.

Insight into the inhibitory potential of metal complexes supported by (E)-2-morpholino-N-(thiophen-2-ylmethylene)ethanamine: synthesis, structural properties, biological evaluation and docking studies

A thiophene-derived Schiff base ligand (E)-2-morpholino-N-(thiophen-2-ylmethylene)ethanamine was used for the synthesis of M(II) complexes, [TEM(M)X2] (M = Co, Cu, Zn; X = Cl; M = Cd, X = Br). Structural characterization of the synthesized complexes revealed distorted tetrahedral geometry around the M(II) center. In vitro investigation of the synthesized ligand and its M(II) complexes showed considerable anti-urease and leishmanicidal potential. The synthesized complexes also exhibited a significant inhibitory effect on urease, with IC50 values in the range of 3.50-8.05 μM. In addition, the docking results were consistent with the experimental results. A preliminary study of human colorectal cancer (HCT), hepatic cancer (HepG2), and breast cancer (MCF-7) cell lines showed marked anticancer activities of these complexes.

Environmentally benign synthesis of unsymmetrical ureas and their evaluation as potential HIV-1 protease inhibitors via a computational approach

The present work reports the cost-effective, high yielding and environmentally acceptable preparation of unsymmetrical ureas from thiocarbamate salts using sodium percarbonate as an oxidant. Efficacy of the unsymmetrical ureas as potential human immune deficiency virus (HIV-1) protease inhibitors has been evaluated via in silico approach. The results revealed interactions of the urea compounds at the active site of the enzyme with favorable binding affinities causing possible mutations hindering the functioning of the enzyme. Further computational assessment of IC50 using known references satisfactorily authenticated the inhibitory action of the selected compounds against HIV-1 protease. Added to the easy synthesis of the ureas following an environmentally benign protocol, this work may be a valuable addition to the ongoing search for drugs with better efficacy profiles and reduced toxicity against HIV.

Design, spectral characterization, quantum chemical investigation, biological activity of nano-sized transition metal complexes of tridentate 3-mercapto-4H-1,2,4-triazol-4-yl-aminomethylphenol Schiff base ligand

A tridentate Schiff base ligand, H2MTIP, was produced by condensing salicylaldehyde with 4-amino-4H-1,2,4-triazole-3-thiol. The ligand was then used to create nanosized complexes of Pt(II), Ni(II), Cu(II), and Pd(II). The complexes have the composition [Pt/Ni/Cu/or Pd(MTIP)(H2O)], this conclusion is supported by molar conductance, magnetic moments, elemental analyses, spectral analyses. In DFT analysis, the 6-31+ g(d,p) basis set was used to fully optimize the energy with respect to the shapes of Schiff base ligand and metal complexes. Pt(II), Ni(II), Cu(II), and Pd(II) complexes have been assigned square-planar geometries. At the same time, the intense diffraction peaks in X-ray diffractograms show their crystalline features with particle sizes in the nanoscale range. The binding interaction of calf thymus DNA with these metal complexes and their insulin-like activity was examined in vitro by inhibiting α-amylase. The study investigated the in-vitro activity of several complexes and identified Pt(II) complex as the one with the highest activity. The researchers then tested this complex for in-vivo antidiabetic activity in induced diabetic rats using the STZ model, and it significantly lowered blood glucose levels. The antioxidant activity and toxicity level of Pt(II) complex were also excellent, suggesting that it could be a good candidate for further research as a possible diabetes drug.Communicated by Ramaswamy H. Sarma.

Visible light-driven photocatalysts, quantum chemical calculations, ADMET-SAR parameters, and DNA binding studies of nickel complex of sulfadiazine

A 3D-supramolecular nickel integrated Ni-SDZ complex was synthesized using sodium salt of sulfadiazine as the ligand and nickel(II) acetate as the metal salt using a condensation process and slow evaporation approach to growing the single crystal. The metal complex was characterized for its composition, functional groups, surface morphology as well as complex 3D structure, by resorting to various analytical techniques. The interacting surface and stability as well as reactivity of the complex were carried out using the DFT platform. From ADMET parameters, human Intestinal Absorbance data revealed that the compound has the potential to be well absorbed, and also Ni-SDZ complex cannot cross the blood-brain barrier (BBB). Additionally, the complex's DNA binding affinity and in-vivo and in-vitro cytotoxic studies were explored utilizing UV-Vis absorbance titration, viscosity measurements, and S. pombe cells and brine shrimp lethality tests. In visible light radiation, the Ni-SDZ complex displayed exceptional photo-degradation characteristics of approximately 70.19% within 70 min against methylene blue (MB).

Computational studies indicated the effectiveness of human metabolites against SARS-Cov-2 main protease

To fight against the devastating coronavirus disease 2019 (COVID-19), identifying robust anti-SARS-CoV-2 therapeutics from all possible directions is necessary. To contribute to this effort, we selected a human metabolites database containing waters and lipid-soluble metabolites to screen against the 3-chymotrypsin-like proteases (3CLpro) protein of SARS-CoV-2. The top 8 hits from virtual screening displayed a docking score varying between ~ - 11 and ~ - 14 kcal/mol. Molecular dynamics simulations complement the virtual screening study in conjunction with the molecular mechanics generalized Born surface area (MM/GBSA) scheme. Our analyses revealed that (HMDB0132640) has the best glide docking score, - 14.06 kcal/mol, and MM-GBSA binding free energy, - 18.08 kcal/mol. The other three lead molecules are also selected along with the top molecule through a critical inspection of their pharmacokinetic properties. HMDB0132640 displayed a better binding affinity than the other three compounds (HMDB0127868, HMDB0134119, and HMDB0125821) due to increased favorable contributions from the intermolecular electrostatic and van der Waals interactions. Further, we have investigated the ligand-induced structural dynamics of the main protease. Overall, we have identified new compounds that can serve as potential leads for developing novel antiviral drugs against SARS-CoV-2 and elucidated molecular mechanisms of their binding to the main protease. Identification of probable hits from human metabolites against SARS-CoV-2 using integrated computational approaches-Missed against MS.

Design, Synthesis, Spectroscopic Inspection, DFT and Molecular Docking Study of Metal Chelates Incorporating Azo Dye Ligand for Biological Evaluation

A new heterocyclic azo dye ligand (L) was synthesized by the combination of 4-amino antipyrine with 4-aminophenol. The new Cr(III), Mn(II), Fe(III), Co(II), Ni(II), Cu(II), Zn(II), and Cd(II) complexes were synthesized in excellent yields. The metal chelate structures were elucidated using elemental analyses, FT-IR, ¹H-NMR, mass, magnetic moment, diffused reflectance spectral and thermal analysis (TG-DTG), and molar conductivity measurement. According to the FT-IR study, the azo dye ligand exhibited neutral tri-dentate behavior, binding to the metal ions with the azo N, carbonyl O, and protonated phenolic OH. The ¹H-NMR spectral study of the Zn(II) complex supported the coordination of the zo dye ligand without proton displacement of the phenolic OH. Diffused reflectance and magnetic moment studies revealed the octahedral geometry of the complexes, as well as their good electrolytic nature, excepting the Zn(II) and Cd(II) complexes, which were nonelectrolytes, as deduced from the molar conductivity study. The theoretical calculations of optimized HOMO-LUMO energies, geometrical parameters, electronic spectra, natural atomic charges, 3D-plots of MEP, and vibrational wavenumbers were computed and elucidated using LANL2DZ and 6-311G (d, p) basis sets of density functional theory (DFT) with the approach of B3LYP DFT and TD-DFT methods. The ligand and complexes have been assayed for their antimicrobial activity and compared with the standard drugs. Most of the complexes have manifested excellent antimicrobial activity against various microbial strains. A molecular docking investigation was also performed, to acquire more information about the binding mode and energy of the ligand and its metal complexes to the Escherichia coli receptor using molecular docking. Altogether, the newly created ligand and complexes showed positive antibacterial effects and are worth future study.

Development of New Azomethine Metal Chelates Derived from Isatin: DFT and Pharmaceutical Studies

Through the condensation of isatin (indoline-2, 3-dione) and aniline in a 1:1 ratio, a Schiff base ligand was synthesized and characterized via (¹H-NMR, mass, IR, UV-Vis) spectra. Elemental analyses, spectroscopy (¹H-NMR, mass, UV-Vis), magnetic susceptibility, molar conductivity, mass spectra, scanning electron microscope (SEM), and thermal analysis have all been used to characterize a series of Cr(III), Mn(II), Fe(III), Co(II), Ni(II), Cu(II), Zn(II), and Cd(II) metal complexes derived from the titled ligand. The metal-to-ligand ratio is 1:1, according to the analytical data. The Schiff base ligand displayed bidentate behavior with NO coordination sites when it bonded to metal ions, as seen by the IR spectra. The magnetic moment measurement and UV-Vis spectral investigation showed the octahedral geometry of the Cr(III), Fe(III), Co(II), Ni(II), and Zn(II) complexes, whereas they suggested the tetrahedral geometry of the Mn(II), Cu(II), and Cd(II) complexes. The thermal analysis study confirmed the presence of both hydrated and coordinated water molecules in all the compounds, except for the Mn(II) complex, and showed that the complexes decomposed in three or five decomposition steps leaving the corresponding metal oxide as a residue. The ligand and its metal complexes' antibacterial efficacy were evaluated. The findings showed that the metal complexes had stronger antibacterial properties than the ligand alone. The ligand and its metal complexes' anticancer properties were also investigated. A DFT investigation is also reported to gather information regarding the electronic features of the ligand and its metal complexes. Finally, drug-likeness and ADME characteristics were also calculated as parameters.

Heteroligand α-Diimine-Zn(II) Complexes with O,N,O'- and O,N,S-Donor Redox-Active Schiff Bases: Synthesis, Structure and Electrochemical Properties

A number of novel heteroligand Zn(II) complexes (1-8) of the general type (Lⁿ)Zn(NN) containing O,N,O'-, O,N,S-donor redox-active Schiff bases and neutral N,N'-chelating ligands (NN) were synthesized. The target Schiff bases LⁿH₂ were obtained as a result of the condensation of 3,5-di-tert-butyl-2-hydroxybenzaldehyde with substituted o-aminophenols or o-aminothiophenol. These ligands with combination with 2,2'-bipyridine, 1,10-phenanthroline, and neocuproine are able to form stable complexes upon coordination with zinc(II) ion. The molecular structures of complexes 4∙H₂O, 6, and 8 in crystal state were determined by means of single-crystal X-ray analysis. In the prepared complexes, the redox-active Schiff bases are in the form of doubly deprotonated dianions and act as chelating tridentate ligands. Complexes 6 and 8 possess a strongly distorted pentacoordinate geometry while 4∙H₂O is hexacoordinate and contains water molecule coordinated to the central zinc atom. The electrochemical properties of zinc(II) complexes were studied by the cyclic voltammetry. For the studied complexes, O,N,O'- or O,N,S-donor Schiff base ligands are predominantly involved in electrochemical transformations in the anodic region, while the N,N'-coordinated neutral nitrogen donor ligands demonstrate the electrochemical activity in the cathode potential range. A feature of complexes 5 and 8 with sterically hindered tert-butyl groups is the possibility of the formation of relatively stable monocation and monoanion forms under electrochemical conditions. The values of the energy gap between the boundary redox orbitals were determined by electrochemical and spectral methods. The parameters obtained in the first case vary from 1.97 to 2.42 eV, while the optical bang gap reaches 2.87 eV.

Innovation of Imine Metal Chelates as Corrosion Inhibitors at Different Media: A Collective Study

The corrosion inhibition of transition metal chelates derived from Schiff base ligands was tested for (mild, copper, stainless, aluminum and carbon) steel in various concentrations of (HCl, HNO₃ and H₂SO₄) acidic medium at 25 °C through (weight loss, potentiodynamic polarization, polarization curves, electrochemical impedance spectroscopy (EIS) and open circuit potential measurements (OCP)) techniques. The studied compounds were identified with various spectral, analytical and physico-chemical techniques. It was observed that the investigated compounds had a significant inhibitory impact on the corrosion of diverse steels in the medium investigated. The analysis shows that increasing the dose of the studied complexes improves the corresponding inhibitory efficiency values. Negative results of Gibb’s free adsorption energy (ΔGads0) prove the suppression process’s spontaneous and physical adsorption, which contradicts the Langmuir adsorption isotherm. As a result of this insight, a novel bridge between nuclearity driven coordinated inorganic chemistry and materials, as well as corrosion control, has been built. This review provides an overview of the use of Schiff bases and associated transition metals as potential corrosion inhibitors, including the factors that influence their application.

Cytotoxic effects of Pd(II) complexes on cancer and normal cells: Their DNA & BSA adduct formation and theoretical approaches

Herein, we report the synthesis and characterisation of a series of Pd(II) complexes: Pd(TEEDA)Cl₂, C-1; [Pd(TEEDA)(OH₂)₂](NO₃)₂, C-2; [Pd(TEEDA)(l-cys)](NO₃)₂, C-3; [Pd(TEEDA)(NALC)], C-4; [Pd(TEEDA)(Meth)](NO₃)₂, C-5; and [Pd(TEEDA)(GSH)], C-6 (where TEEDA = N,N,N'-Triethylenediamine, l-cys = l-cysteine, NALC = N-acetyl-l-cysteine, Meth = dl-methionine and GSH = glutathione). UV-Vis spectroscopic characterisation was supported by TD-DFT theoretical simulation using Gaussian09 software. Different reactivity parameters were calculated from the energy difference between HOMO and LUMO of the complexes by DFT. The bonding mode of the labile ligands was confirmed by NBO analysis. Interaction of the complexes with DNA has been observed by gel electrophoresis experiment. DNA binding nature as well as binding constants of the complexes were measured with UV-Vis and fluorescence spectroscopic method. The binding nature of the complexes with DNA was confirmed by viscometric titration. Interaction of the complexes with BSA was investigated by UV-Vis and fluorescence titration method. Cytotoxic activity of the Pd(II) complexes was evaluated on A549 (lung carcinoma epithelial cells), HCT116(Colorectal Carcinoma) and HEK293 (Human embryonic kidney cells) cell lines. The ROS generation in the presence of the complexes was tested both on cancer cell lines A549 and HCT116 as well as human normal cell HEK293.

Design, Structural Inspection and Bio-Medicinal Applications of Some Novel Imine Metal Complexes Based on Acetylferrocene

Some novel imine metal chelates with Cr³⁺, Mn²⁺, Fe³⁺, Co²⁺, Ni²⁺, Cu²⁺, Zn²⁺, and Cd²⁺ cations were produced from 2-acetylferrocene and 3-aminophenol. The new acetylferrocene azomethine ligand ((Z)-cyclopenta-1,3-dien-1-yl(2-(1-((3-hydroxyphenyl)imino)ethyl)cyclopenta-2,4-dien-1-yl)iron) and its metal ion chelates were constructed and elucidated using FT-IR, UV/Vis, ¹HNMR, DTA/TGA, CHNClM studies, mass spectrometry and SEM analysis. According to the TGA/DTG investigation, the ferrocene moiety spontaneously disintegrates to liberate FeO. The morphology of the free acetylferrocene azomethine via SEM analysis was net-shaped with a size of 64.73 nm, which differed in Cd(II) complex to be a spongy shape with a size of 42.43 nm. The quantum chemical features of the azomethine ligand (HL) were computed, and its electronic and molecular structure was refined theoretically. The investigated acetylferrocene imine ligand behaves as bidinetate ligand towards the cations under study to form octahedral geometries in case of all complexes except in case of Zn²⁺ is tetrahedral. Various microorganisms were used to investigate the anti-pathogenic effects of the free acetylferrocene azomethine ligand and its metal chelates. Moreover, the prepared ligand and its metal complexes were tested for anticancer activity utilizing four different concentrations against the human breast cancer cell line (MCF7) and the normal melanocyte cell line (HBF4). Furthermore, the binding of 3-aminophenol, 2-acetylferrocene, HL, Mn²⁺, Cu²⁺, and Cd²⁺ metal chelates to the receptor of breast cancer mutant oxidoreductase was discovered using molecular docking (PDB ID: 3HB5).

Development of Metal Complexes for Treatment of Coronaviruses

Coronavirus disease (SARS-CoV-2) is a global epidemic. This pandemic, which has been linked to high rates of death, has forced some countries throughout the world to implement complete lockdowns in order to contain the spread of infection. Because of the advent of new coronavirus variants, it is critical to find effective treatments and vaccines to prevent the virus’s rapid spread over the world. In this regard, metal complexes have attained immense interest as antibody modifiers and antiviral therapies, and they have a lot of promise towards SARS-CoV-2 and their suggested mechanisms of action are discussed, i.e., a new series of metal complexes’ medicinal vital role in treatment of specific proteins or SARS-CoV-2 are described. The structures of the obtained metal complexes were fully elucidated by different analytical and spectroscopic techniques also. Molecular docking and pharmacophore studies presented that most of complexes studied influenced good binding affinity to the main protease SARS-CoV-2, which also was attained as from the RCSB pdb (Protein Data Bank) data PDB ID: 6 W41, to expect the action of metal complexes in contradiction of COVID-19. Experimental research is required to determine the pharmacokinetics of most of the complexes analyzed for the treatment of SARS-CoV-2-related disease. Finally, the toxicity of a metal-containing inorganic complex will thus be discussed by its capability to transfer metals which may bind with targeted site.

Syntheses, in vitro, and in silico studies of rhodanine-based schiff bases as potential α-amylase inhibitors and radicals (DPPH and ABTS) scavengers

A two-step reaction method was used to synthesize a series of rhodanine-based Schiff bases (2-33) that were characterized using spectroscopic techniques. All compounds were assessed for α-amylase inhibitory and radical scavenging (DPPH and ABTS) activities. In comparison to the standard acarbose (IC₅₀ = 9.08 ± 0.07 µM), all compounds demonstrated good to moderate α-amylase inhibitory activity (IC₅₀ = 10.91 ± 0.08-61.89 ± 0.102 µM). Compounds also demonstrated significantly higher DPPH (IC₅₀ = 10.33 ± 0.02-96.65 ± 0.03 µM) and ABTS (IC₅₀ = 12.01 ± 0.12-97.47 ± 0.13 µM) radical scavenging activities than ascorbic acid (DPPH, IC₅₀ = 15.08 ± 0.03 µM; ABTS, IC₅₀ = 16.09 ± 0.17 µM). The limited structure-activity relationship (SAR) suggests that the position and nature of the substituted groups on the phenyl ring have a vital role in varying inhibitory potential. Among the series, compounds with an electron-withdrawing group at the para position showed the highest potency. Kinetic studies revealed that the compounds followed a competitive mode of inhibition. Molecular docking results are found to agree with experimental findings, showing that compounds reside in the active pocket due to the main rhodanine moiety.

Synthesis, Spectroscopic, Structural and Molecular Docking Studies of Some New Nano-Sized Ferrocene-Based Imine Chelates as Antimicrobial and Anticancer Agents

The newly synthesized organometallic acetyl ferrocene imine ligand (HL) was obtained by the direct combination of 2-acetyl ferrocene with 2-aminothiophenol. The electronic and molecular structure of acetyl ferrocene imine ligand (HL) was refined theoretically and the chemical quantum factors were computed. Complexes of the acetyl ferrocene imine ligand with metal(II)/(III) ions (Cr(III), Mn(II), Fe(III), Co(II), Ni(II), Cu(II), Zn(II) and Cd(II)) were fabricated. They were inspected by thermal (DTG/TG), spectroscopic techniques (FT-IR, 1H NMR, mass, UV-Vis), molar conductivity, and CHNClM to explicate their structures. Studies using scanning electron microscope (SEM) were conducted on the free acetyl ferrocene imine ligand and its Cd(II) chelate to confirm their nano-structure. To collect an idea about the effect of metal ions on anti-pathogenic properties upon chelation, the newly synthesized acetyl ferrocene imine ligand and some of its metal chelates were tested against a variety of microorganisms, including Bacillus subtilis, Staphylococcus aureus, Salmonella typhimurium, Escherichia coli, Aspergillus fumigatus, and Candida albicans. The ligand and its metal chelate were tested for cytotoxic activity in human cancer (MCF-7 cell viability) and human melanocyte cell line HBF4. It was discovered that the Cd(II) chelate had the lowest IC50 of the three and thus had the prior activity. Molecular docking was utilized to investigate the interaction of acetyl ferrocene imine ligand (HL) with the receptors of the vascular endothelial growth factor receptor VEGFR (PDB ID: 1Y6a), human Topo IIA-bound G-segment DNA crystal structure (PDB ID: 2RGR), and Escherichia coli crystal structure (PDB ID: 3T88).

Synthesis, Characterization, Biological Activity and Molecular Docking Studies of Novel Organotin(IV) Carboxylates

Four new carboxylates complexes with general formula R₂SnL₂ and R₃SnL, where R = n-butyl (1, 3), methyl (2, 4) and L = 4-Chlorophenoxyacetate, were synthesized in significant yields. FT-IR analysis revealed a chelating (1 and 2) and a bridging bidentate (3 and 4) coordination modes for the carboxylate ligand in solid state which was further confirmed by the single crystal X-ray analysis of complex 4. The NMR data (¹H, ¹³C and ¹¹⁹Sn) revealed a higher coordination number around the tin center in R₂SnL₂ (1 and 2) compared to R₃SnL (3 and 4). A close matching was observed between the experimental and calculated structures (obtained at B3LYP/6-31G* + LANL2DZ basis set). Quantum chemical analysis indicates that the carboxylate moiety has the major contribution in the formation of filled and unfilled orbitals as well as in ligand to ligand intramolecular charge transfer during the electronic transitions. The cytotoxicity data of the screened compounds evaluated against lung cancer cell line (A549) and normal lung fibroblast cell line (MRC-5) revealed that 1, 3 and 4 have shown dose dependent cytotoxic effects while HL and 2 have shown steady and low cytotoxic activities. The antibacterial activity of complexes 1–4 is higher than that of HL. Molecular docking study showed an intercalation binding mode for complex 3 with DNA (docking score = −3.6005) involving four polar interactions. Complex 3 docking with tubulin (PDB ID 1SA0) with colchicine as a target protein resulted in three polar interactions (docking score −5.2957). Further, the docking analysis of the HL and 1–4 has shown an adequate interactions with the coronavirus SARS-CoV-2 spike protein, nucleocapsid protein and human angiotensin converting enzyme (ACE2).

Fabrication, DFT Calculation, and Molecular Docking of Two Fe(III) Imine Chelates as Anti-COVID-19 and Pharmaceutical Drug Candidate

Two tetradentate dibasic chelating Schiff base iron (III) chelates were prepared from the reaction of 2,2′-((1E,1′E)-(1,2-phenylenebis(azanylylidene))bis(methanylylidene))bis(4-bromophenol) (PDBS) and 2,2′-((1E,1′E)-((4-chloro-1,2-phenylene)bis(azanylylidene))-bis(methanylylidene))bis(4-bromophenol) (CPBS) with Fe³⁺ ions. The prepared complexes were fully characterized with spectral and physicochemical tools such as IR, NMR, CHN analysis, TGA, UV-visible spectra, and magnetic moment measurements. Moreover, geometry optimizations for the synthesized ligands and complexes were conducted using the Gaussian09 program through the DFT approach, to find the best structures and key parameters. The prepared compounds were tested as antimicrobial agents against selected strains of bacteria and fungi. The results suggests that the CPBSFe complex has the highest activity, which is close to the reference. An MTT assay was used to screen the newly synthesized compounds against a variety of cell lines, including colon cancer cells, hepatic cellular carcinoma cells, and breast carcinoma cells. The results are expressed by IC50 value, in which the 48 µg/mL value of the CPBSFe complex indicates its success as a potential anticancer agent. The antioxidant behavior of the two imine chelates was studied by DPPH assay. All the tested imine complexes show potent antioxidant activity compared to the standard Vitamin C. Furthermore, the in vitro assay and the mechanism of binding and interaction efficiency of the tested samples with the receptor of COVID-19 core protease viral protein (PDB ID: 6lu7) and the receptor of Gram-negative bacteria (Escherichia coli, PDB ID: 1fj4) were investigated using molecular docking experiments.

Spectrophotometric and fluorometric detection of DNA/BSA interaction, antimicrobial, anticancer, antioxidant and catalytic activities of biologically active methoxy substituted pyrimidine-ligand capped copper nanoparticles

New Schiff base ligand (DPMN) was synthesized from the condensation of 2-hydroxy-5-nitrobenzaldehyde and 2-amino-4,6-dimethoxypyrimidine which was confirmed by spectroscopic and analytical methods. Solid air stable copper nanoparticles (DPMN-CuNPs) were synthesized from its copper chloride salt and it is stabilized by the prepared Schiff base ligand by phase transfer assisted synthesis which is a modified Brust-Schiffrin technique. The formation of ligand stabilized copper nanoparticles was confirmed by UV-Visible and FT-IR spectroscopic techniques. The size, surface morphology and quality of DPMN-CuNPs were analyzed by SEM and TEM techniques. Antioxidant activities of DPMN and DPMN-CuNPs with DPPH, SOD, peroxide and nitrous oxide were analyzed by electronic absorption spectroscopy. DNA interaction between DPMN and DPMN-CuNPs with CT-DNA was carried out using electronic absorption, fluorescence, viscometric measurements and cyclic voltammetric techniques. Interaction between BSA and the synthesized compounds analyzed by electronic absorption spectroscopy, Antimicrobial studies confirmed that the synthesized DPMN-CuNPs possess significant biological activities than DPMN. Anticancer results suggest that prepared DPMN-CuNPs have significant anticancer activity against different cancer cell lines and least toxic effect against the normal (NHDF) cell line. Other than the positive response in biological evaluation, our DPMN-CuNPs possess good catalytic activity in methyl orange reduction, methylene blue degradation and nitro phenol reduction.

Anthranilamides with quinoline and β-carboline scaffolds: design, synthesis, and biological activity

In the present study, we report the design and synthesis of novel amide-type hybrid molecules based on anthranilic acid and quinoline or β-carboline heterocyclic scaffolds. Three types of biological screenings were performed: (i) in vitro antiproliferative screening against a panel of solid tumor and leukemia cell lines, (ii) antiviral screening against several RNA viruses, and (iii) anti-quorum sensing screening using gram-negative Chromobacterium violaceum as the reporter strain. Antiproliferative screening revealed a high activity of several compounds. Anthranilamides 12 and 13 with chloroquine core and halogenated anthranilic acid were the most active agents toward diverse cancer cell lines such as glioblastoma, pancreatic adenocarcinoma, colorectal carcinoma, lung carcinoma, acute lymphoblastic, acute myeloid, chronic myeloid leukemia, and non-Hodgkin lymphoma, but also against noncancerous cell lines. Boc-protected analogs 2 and 3 showed moderate activities against the tested cancer cells without toxic effects against noncancerous cells. A nonhalogenated quinoline derivative 10 with N-benzylanthranilic acid residue was equally active as 12 and 13 and selective toward tumor cells. Chloroquine and quinoline anthranilamides 10-13 exerted pronounced antiviral effect against human coronaviruses 229E and OC43, whereas 12 and 13 against coronavirus OC43 (EC₅₀ values in low micromolar range; selectivity indices from 4.6 to > 10.4). Anthranilamides 14 and 16 with PQ core inhibited HIV-1 with EC₅₀ values of 9.3 and 14.1 µM, respectively. Compound 13 displayed significant anti-quorum/biofilm effect against the quorum sensing reporter strain (IC₅₀ of 3.7 μM) with no apparent bactericidal effect.

Transition metal complexes of triazole-based bioactive ligands: synthesis, spectral characterization, antimicrobial, anticancer and molecular docking studies

In the present research work, four new heterocyclic Schiff base ligands (1–4) were synthesized by the condensation of 4-(4-amino-5-mercapto-4H-1,2,4-triazol-3-yl)phenol with salicylaldehyde derivatives in 1:1 molar ratio. The synthesized Schiff base ligands were allowed for complexation with Co(II), Ni(II), Cu(II), Zn(II) metal ions. The structure of the newly synthesized compounds (1–20) was elucidated with the help of various spectral and physicochemical techniques. Spectroscopic data confirm the tridentate nature of ligands which coordinate to the metal via deprotonated oxygen, azomethine nitrogen and thiol sulphur. Conductivity data showed the non-electrolytic nature of complexes. Furthermore, the synthesized compounds were evaluated for their in-vitro antimicrobial activity against four pathogenic bacterial strains and two pathogenic fungal strains. The observed results of microbial activity reveals that compound 3 and its complexes (13–16) were found most potent against the pathogenic strains. In addition, the anticancer activity of all the synthesized compounds was evaluated against human carcinoma cell lines i.e. HCT-116, DU145 and A549 using MTT assay. Among the tested compounds 12, 19, and 20 were found to show promising potency against the cancer cell lines. To rationalize the preferred modes of interaction of most potent compounds with the active site of human EGFR protein (PDB id: 5XGM), molecular docking studies were performed.

Schiff bases and their metal complexes with biologically compatible metal ions; biological importance, recent trends and future hopes

Schiff bases are in the field of medicinal and material chemistry for a long time. There are several advancements from time to time towards facile synthesis and potential applications. As medicines they have been applied as organic molecules as well as their metal complexes. The activities of metal complexes have been found to increase due to increase lipophilicity in comparison to the corresponding free ligand. Besides simple coordination compounds they have been applied as ionic liquid (IL)- supported and IL-tagged species with far enhanced efficiency. Among metal complexes recent advancement deals with photodynamic therapy to treat a number of tumors with fewer side effects. Schiff bases are efficient ligands and their complexes with almost all metal ions are reported. This mini-review article deals with complexes of Schiff bases with biologically compatible metal ions, Co(II), Cu(II), Zn(II), Pd(II), Ag(I), Pt(II) and their potential uses to combat cancerous cells. Strong hopes are associated with photodynamic therapy and IL-tagged and IL-supported Schiff bases and their complexes.