Synthesis and structure of new dicopper(II) complexes bridged by N-(2-hydroxy-5-methylphenyl)-N'-[3-(dimethylamino)propyl]oxamide with in vitro anticancer activity: A comparative study of reactivities towards DNA/protein by molecular docking and experimental assays

Copper(II) complexes of a furan-containing aroylhydrazonic ligand: syntheses, structural studies, solution chemistry and interaction with HSA

Copper(II) complexes have become a potential alternative to the use of platinum drugs in cancer therapy due to their multi-target mode of action. In this context, we report the syntheses of new mononuclear and dinuclear coordination compounds of this element, 1 and 2, derived from the ligand 5-methylsalicylaldehyde 2-furoyl hydrazone (H2L). All three compounds were structurally and spectroscopically characterized, both in the solid state and in solution. In 1, Cu is coordinated by three donor-atoms from the hydrazonic ligand and one chloride ion. H2L is deprotonated at the phenol oxygen. The dinuclear complex 2 is, on the other hand, a dimeric form of 1 in which the chloride ions of a pair of mononuclear units are lost and phenoxo bridges take their places, double-connecting the metal centres and resulting in a single species with the ligand fully deprotonated. The compounds were fairly stable in aqueous medium at room temperature. An experimental-theoretical combined approach demonstrated that all of them are able to bind human serum albumin (HSA), although at different sites and with diverse stoichiometries and affinities (as concluded by the calculated binding energies). In view of this, and due to the well-known antiproliferative activity of hydrazone-containing copper complexes, we consider the compounds presented in here promising, and believe that they deserve more profound studies regarding the assessment of their potential against tumour cell lines.

Syntheses, crystal structures of two Fe(III) Schiff base complexes with chelating o-vanillin aroylhydrazone and exploration of their bio-relevant activities

Two novel Fe(III) complexes, Fe(HL¹)₂Cl·1.25H₂O (1) and Fe(HL²)₂·Et₃NH·H₂O (2) (H₂L¹ = o-vanillin benzoylhydrazone, H₃L² = o-vanillin salicylhydrazone) are prepared. X-ray single crystal diffraction confirms that the hydrazone ligands can be chelated to iron centre resulting in a six-coordinate octahedral configuration. Both complexes show major intercalation effect to the herring sperm deoxyribonucleic acid (HS-DNA) with high binding constants of 2.01 × 10⁴ M^-1 and 2.24 × 10⁴ M^-1, respectively. Molecular docking studies reveal both complexes can intercalate at the gap of DC5-DG2 and DG6-DC1 base pairs of DNA hexamer (1Z3F). The interaction of the complex 1 with plasmid pBR322 DNA induces distinguishable alterations of the DNA morphology. Further, the structure of plasmid pBR322 DNA treated with complex 1 in the presence of ascorbic acid has been damaged probably due to the reactive oxygen species (ROS) generation. What's more, both complexes show high affinity with bovine serum albumin (BSA), the binding constants measured by fluorescence techniques are 5.75 × 10⁶ M^-1 and 4.39 × 10⁷ M^-1, respectively. Molecular docking demonstrates that the complexes prefer the binding pocket of site III (subdomain IIB) of BSA (PDB ID: 4F5S). Similarly, dynamic light scattering (DLS) reveals that the complexes not only bind to BSA but also induce bigger size aggregates as the concentration increases.

Nano-Azo Ligand and Its Superhydrophobic Complexes: Synthesis, Characterization, DFT, Contact Angle, Molecular Docking, and Antimicrobial Studies

Metal complexes of the 2,2'-(1,3-phenylenebis(diazene-2,1-diyl))bis(4-aminobenzoic acid) diazo ligand (H2L) derived from m-phenylenediamine and p-aminobenzoic acid were synthesized and characterized by different spectral, thermal, and analytical tools. The H2L ligand reacted with the metal ions Cr(III), Mn(II), Fe(III), Co(II), Ni(II), Cu(II), Zn(II), and Cd(II) as 1 : 1 stoichiometry. All complexes displayed an octahedral geometry according to the electronic and magnetic moment measurements. The IR spectra revealed the binding of the azo ligand to the metal ions via two azo nitrogen atoms and protonated carboxylate O in a neutral tetradentate manner. Both IR and 1H NMR spectra documented the involvement of the carboxylate group without proton displacement. The thermal studies pointed out that the complexes had higher thermal stability comparable with that of the free ligand. SEM images revealed the presence of the diazo ligand and its Cd(II) complex in a nanostructure form. The contact angle measurements proved that the Cd(II) complex can be considered as a superhydrophobic material. The molecular and electronic structure of H2L and [Cd(H2L)Cl2].H2O were optimized theoretically, and the quantum chemical parameters were calculated. The biological activities of the ligand, as well as its metal complexes, have been tested in vitro against some bacteria and fungi species. The results showed that all the tested compounds have significant biological activities with different sensitivity levels. The binding between H2L and its Cd(II) complex with receptors of the crystal structure of S. aureus (PDB ID: 3Q8U), crystal structure of protein phosphatase (PPZ1) of Candida albicans (PDB ID: 5JPE), receptors of breast cancer mutant oxidoreductase (PDB ID: 3HB5), and crystal structure of Escherichia coli (PDB ID: 3T88) was predicted and given in detail using molecular docking.

Cocrystallization of 5-fluorouracil and l-phenylalanine: the first zwitterionic cocrystal of 5-fluorouracil with amino acid exhibiting perfect in vitro/vivo pharmaceutical properties

The first zwitterionic cocrystal of 5-fluorouracil with amino acid has been prepared and its structure and in vitro/vivo properties have been systematically studied.

Synthesis, DNA/BSA binding studies and in vitro biological assay of nickel(II) complexes incorporating tridentate aroylhydrazone and triphenylphosphine ligands

Two new nickel (II) triphenylphosphine complexes derived from tridentate aroylhydrazone ligands [H2L1 = 2-hydroxy-3-methoxybenzylidene)benzohydrazone and H2L2 = N'-(2-hydroxy-3-methoxybenzylidene)-2-hydroxybenzoylhydrazone] and triphenylphosphine were prepared and their molecular structures were determined by single crystal X-ray diffraction analysis. Both nickel(II) complexes showed slightly distorted square planar geometry with one tridentate aroylhydrazone ligand coordinated through ONO donor atoms and one triphenylphosphine ligand coordinated to the nickel center through the phosphorus atom. DNA interaction studies indicated that both complexes possessed higher affinity to herring sperm DNA (HS-DNA) than the corresponding free aroylhydrazone ligand. Molecular docking investigations showed that both complexes could bind to DNA through intercalation of the phenyl rings between adjacent base pairs in the double helix. Meanwhile, bovine serum albumin (BSA) binding studies revealed the complexes could effectively interact with BSA and change the secondary structure of BSA. Further pharmacological evaluations of the synthesized complexes by in vitro antioxidant assays demonstrated high antioxidant activity against NO· and O2˙- radicals. The anticancer activity of each complex was assessed through in vitro cytotoxicity assays (CCK-8 kit) toward A549 and MCF-7 cancer cell and normal L-02 cell lines. Significantly, the Ni(II) complex derived from H2L1 ligand was found to be more effective cytotoxic toward MCF-7cancerous cell with the IC50 value equaled 9.7 μM, which showed potent cytotoxic activity over standard drug cisplatin. AbbreviationsA549human lung carcinoma cellBSAbovine serum albuminCCK-8Cell Counting Kit-8DFTdensity functional theoryDNAdeoxyribonucleic acidDPPH˙2,2-diphenyl-1-picrylhydrazylH2L12-hydroxy-3-methoxybenzylidene)benzohydrazone N'-(2-hydroxy-3-methoxybenzylidene)-2-hydroxybenzoylhydrazoneH2L2N'-(2-hydroxy-3-methoxybenzylidene)-2-hydroxybenzoylhydrazoneHOMOhighest occupied molecular orbitalIC50the 50% activityL-02human normal liver cellLOMOlowest unoccupied molecular orbital (LUMO)MCF-7human breast carcinoma cellNO˙nitric oxideO2˙-superoxide anionSODsuperoxide dismutaseCommunicated by Ramaswamy H. Sarma.

Synthesis, structure, and biological active evaluation of a new cyclic tetranuclear copper(II) complex bridged both by oxamido and carboxylate groups

A new tetracopper(II) complex bridged both by oxamido and carboxylato groups, namely [Cu₄ (dmaepox)₂ (bpy)₂ ](NO₃ )₂ ·2H₂ O, where H₃ dmaepox and bpy represent N-benzoato-N'- (3-methylaminopropyl)oxamide and 2,2'-bipyridine, was synthesized, and its structure reveals the presence of a centrosymmetric cyclic tetracopper(II) cation assembled by a pair of cis-dmaepox^3- - bridged dicopper(II) units through the carboxylato groups, in which the endo- and exo-copper(II) ions bridged by the oxamido group have a square-planar and a square-pyramidal coordination geometries, respectively. The aromatic packing interactions assemble the complex molecules to a two-dimensional supramolecular structure. The reactivity toward DNA and protein bovine serum albumin (BSA) indicates that the complex can interact with herring sperm DNA through the intercalation mode and the binding affinity is dominated by the hydrophobicity and chelate ring arrangement around copper(II) ions and quenches the intrinsic fluorescence of BSA via a static process. The cytotoxicity of the complex shows selective cancer cell antiproliferative activity.

Cadmium(ii) complexes with a 4-acyl pyrazolone derivative and co-ligands: crystal structures and antitumor activity

The antitumor activity of three mononuclear cadmium(ii) complexes and an apoptosis assay of complex 3 were investigated.