Crystal structure, DNA interactions, antioxidant and antitumor activity of thermally stable Cu(II), Ni(II) and Co(III) complexes of an N,O donor Schiff base ligand

A mononuclear N,N,N,O donor schiff base Cu(II) complex inhibits bacterial biofilm formation and promotes apoptosis and cell cycle arrest in prostate cancer cells

In this work, we report a distorted square pyramidal mononuclear copper(II) complex [Cu(L)(NCS)] (1) which was obtained by the reaction of the aqueous solution of ammonium thiocyanate to a methanolic solution of copper nitrate trihydrate and corresponding Schiff-base ligands. Schiff bases, HL (C12H19N3O) act as a tetradentate Schiff base, derived from 1:1 condensation of o-hydroxyacetophenone and diethylenetriamine. The synthesized complex has been successfully characterized based on elemental analysis and Infrared (IR) spectroscopy. The structure of complex 1 was confirmed by single-crystal X-ray diffraction study. In our study, we investigated synthesis, structural characterization, antimicrobial, anti-biofilm, and anti-cancer activity, and plausible mechanism of action of a novel mononuclear copper(II) schiff base complex. Increasing microbial resistance to several commercially available or traditional antimicrobial compounds has become a major global health concern at present time. The mononuclear copper(II) complex exhibited potential antibacterial activity against two strains of the gram-negative pathogen Pseudomonas aeruginosa. The copper compound dependent damage of bacterial cell membrane and inhibition of bacterial biofilm formation were also identified. Moreover, complex 1 inhibited prostate cancer cell growth, and migration by inducing apoptosis and arresting the cell cycle at the G2/M phase. Based on the results, we are suggesting our novel mononuclear copper(II) compound as a potential candidate for the development of new antibacterial and anti-cancer drugs.

Synthesis, characterization, solution chemistry and anticancer activity of [NiCl2(Ph2P-N(R)-PPh2)] (R = 2-CH2Py, CH2Ph and p-tol) complexes

In this work three Ni²⁺ complexes with general formula [NiCl₂(Ph₂P-N(R)-PPh₂)], R = 2-CH₂Py (Py = pyridine) - 1, CH₂Ph (Ph = phenyl) - 2 and p-tol (p-tol = p-tolyl) - 3, were synthesized and characterized. These complexes were obtained in high yield by the reaction of NiCl₂.6H₂O and the corresponding diphenylphosphinoamine ligand (Ph₂P-N(R)-PPh₂) in CH₂Cl₂/MeOH (1:1) solution, at room temperature (∼25 °C), and characterized by ¹H and ³¹P {¹H} NMR, vibrational spectroscopy in the infrared region, electronic spectroscopy in the UV-Vis regions, elemental analysis (%C, %H, %N) and single-crystal X-ray diffraction. The solution chemistry was studied in CDCl₃/dmso-d⁶ (dimethylsulfoxide) or neat dmso-d⁶ using complex 2 as a model. The complexes were evaluated as cytotoxic agents against two cancer cells lines, A549 (lung cancer cells), B16F10 (melanoma cells) and the health cells HaCaT (human epithelial keratinocytes).

Antitumor activity of synthetic three copper(II) complexes with terpyridine ligands

Three new synthetic terpyridine copper(II) complexes were characterized. The copper(II) complexes induced apoptosis of three cancer cell lines and arrested T-24 cell cycle in G1 phase. The complexes were accumulated in mitochondria of T-24 cells and caused significant reduction of the mitochondrial membrane potential. The complexes increased both intracellular ROS and Ca²⁺ levels and activated the caspase-3/9 expression. The apoptosis was further confirmed by Western Blotting analysis. Bcl-2 was down-regulated and Bax was upregulated after treatment with complexes 1-3. The in vivo studies showed that complexes 1-3 obviously inhibited the growth of tumor without significant toxicity to other organs.

Biologically active oxovanadium(IV) Schiff base metal complex: antibacterial, antioxidant, biomolecular interaction and molecular docking studies

The oxovanadium(IV) Schiff base metal complex (ISNPV) have been synthesized as well as characterized by using micro analytical and traditional spectroscopic techniques. The spectral findings were utilized to validate the formation of ISNPV with structure exhibited square pyramidal geometry. The in vitro antibacterial activities of ISNPV were investigated to five different bacterial stains such as S. aureus, S. epidermidis, B. cereus, B. amyloliquefaciens and B. subtilis. The obtained result have suggested that the ISNPV has highest antibacterial activity against S. aureus than the other bacterial stains. The in vitro antioxidant activity like DPPH free radical scavenging assay method was studied by ISNPV in DMSO medium. Because it scavenges all free radicals, the ISNPV possesses higher antioxidant activity than the free ligand. UV-visible absorption and emission spectral techniques were used to investigate the binding of CT-DNA to the ISNPV. Both the spectral data indicate that the ISNPV binds the double helix structure of CT-DNA via an intercalation mode. Additionally, investigate the interactions of ISNPV with the protein molecules like BSA/HAS has been investigated using absorption and emission techniques. The absorption intensity of metal complex increases as well as the emission intensity of protein molecules ability decreases due to the binding nature of ISNPV with BSA/HSA protein molecules. The binding nature of ISNPV with bio molecules such as CT-DNA, BSA and HSA was also validated using molecular docking approach.

Preparation, Characterization of New Antimicrobial Antitumor Hybrid Semi-Organic Single Crystals of Proline Amino Acid Doped by Silver Nanoparticles

Proline is water soluble amino acid extensively used in drug delivery systems. Compounds of cobalt (Co) transition metal have potent antimicrobial and anticancer activities. However, a drug delivery system combining proline cobalt is not reported yet. For the first time, new hybrid semi-organic single crystals of proline cobalt chloride (PCC) are prepared. The novelty of the article is also that single crystal proline cobalt chloride showed potent antimicrobial and antitumor activity. Doping of PCC by Ag⁰NPs significantly increased these biological activities. The anisotropic magnetic properties of single crystals can mitigate the cytotoxicity of Ag⁰NPs on normal cells. Silver nanoparticles (Ag⁰NPs) improved the crystal habits and physicochemical properties. Ag⁰NPs showed the best performance, paramagnetic materials n-type semiconductors due to delocalized excess electrons of Ag⁰NPs incorporated in the crystal lattice interstitially. Crystals have high absorptivity for UV-radiation electromagnetic radiation. Ag⁰NPs enhanced AC electrical conductivity up to 2.3 × 10⁴ Ω cm^-1 due to high electron density. Proline doped crystals are obtained in good purity as triclinic unit cell with having anisotropic magnetism. PCCAg⁰NPs crystal exhibited: high antimicrobial activities to various bacterial and fungal species, inhibition zone (mm): 21, 25, 24, 26, 30, 28, 12, and 46 for S. aureus, E. faecalis, S. typhi, E. coli, P. aerugino, K. pneumoniae, A. braselienses, and C. albicans, respectively, in comparison to ciprofloxacin antibiotic (23, 0, 26, 26, 25, 0, 0, 0) for the same tested species, respectively; higher cytotoxicity against breast cancer cells (IC₅₀ 22.1 μM) than the reference drug cisplatin (IC₅₀ 11.7 μM); and lower cytotoxicity to normal healthy lung cells MRC-5, (IC₅₀ 145.5 μM) than cisplatin (IC₅₀ 30.2 μM). Hence, this crystal is a candidate for chemotherapy of breast cancer.

Water-soluble nickel (II) Schiff base complexes: Synthesis, structural characterization, DNA binding affinity, DNA cleavage, cytotoxicity, and computational studies

Two water-soluble nickel (II) Schiff base complexes were prepared and their interaction with fish sperm DNA (FS-DNA) was investigated by various methods including UV-vis spectroscopy, fluorescence spectroscopy, cyclic voltammetry, and viscometric measurements. Complex 1: [N,N'-bis{5-[(triphenyl phosphonium chloride)-methyl] salicylidine}-3,4-diaminobenzophenone]nickel(II) perchloride dihydrate: [Ni(5-CH₂PPh₃-3,4-salophen)] (ClO₄)₂.2 H₂O was synthesized as a new complex and characterized by elemental analysis, IR, ¹H NMR, thermal gravimetric analysis (TGA) and UV-vis spectroscopy. Complex 2: sodium [(N,N'-bis(5-sulfosalicyliden)-3, 4-diaminobenzophenone)aqua] nickel(II) hydrate: Na₂[Ni (5-SO₃-3,4-salbenz)(H₂O)]. H₂O was already synthesized by our research team, but in this study, its function as a DNA-binding compound was tested, and compared with the results of complex 1-DNA binding. The calculation of different constants using absorption and emission data, all confirmed the stronger binding ability of complex 1 than complex 2 with DNA. Different thermodynamic parameters showed the interactions between DNA and complexes were the type of hydrophobic interaction for complex 1 and electrostatic interaction for complex 2. Also, the negative values of free energy changes proved a spontaneous DNA binding process. Based on cell toxicity assay against two different cell lines including Jurkat and MCF-7, the effect of complex 1 was comparable to cisplatin, and the toxicity mechanism was further justified by bright field microscopy, flow cytometry, and cleavage of DNA in the presence of H₂O₂. Besides, the docking calculations suggested intercalation after measuring the lowest-energy between the complexes and DNA. For both complexes, all analytical, spectroscopic, and molecular modeling methods supported partial intercalation as the main binding mode between the complexes and DNA.

A Treatise on Furan Cored Schiff Base Cu(II), Ni(II) and Co(III) Complexes Accentuating Their Biological Efficacy: Synthesis, Thermal and Spectroscopic Characterization, DNA Interactions, Antioxidant and Antibacterial Activity Studies

Three metal complexes [Cu(FMIMDIP)₂ ] (1), [Ni(FMIMDIP)₂ ] (2) and [Co(FMIMDIP)₃ ] (3) where, FMIMDIP=(((furan-2-yl)methylimino)methyl)-4,6-diiodophenol, were synthesized and characterized by various spectroscopy. The analytical data revealed a square planar geometry for 1 and 2 and an octahedral geometry for 3. The kinetic and thermodynamic parameters of the thermal decomposition steps were calculated from the thermograms. The quantum chemical parameters have been calculated using HOMO-LUMO energies and reveal the stability of the complexes. The DNA interaction of 1-3 towards calf-thymus DNA was investigated by absorption titration, fluorescence spectroscopy and gel electrophoresis. All the complexes bind to DNA via intercalation mode with binding constant (K_b ) values of 4.17×10³  M^-1 to 5.9×10⁴  M^-1 and also effectively cleave pBR322 DNA by oxidative and photolytic techniques. The synergistic action of metal chelates with ascorbic acid induced the generation of free radicals. The antibacterial activity of 1-3 was tested against B. thuringiensis, S. pneumoniae, E. coli, and P. putida. Complex 3 has the best activity among all the complexes.

Terpyridine copper(II) complexes as potential anticancer agents by inhibiting cell proliferation, blocking the cell cycle and inducing apoptosis in BEL-7402 cells

Four mononuclear terpyridine complexes [Cu(H-L^a)Cl₂]·CH₃OH (1), [Cu(H-L^a)Cl]ClO₄ (2), [Cu(H-L^b)Cl₂]·CH₃OH (3), and [Cu(H-L^b)(CH₃OH)(DMSO)](ClO₄)₂ (4) were prepared and fully characterized. Complexes 1-4 exhibited higher cytotoxic activity against several tested cancer cell lines especially BEL-7402 cells compared to cisplatin, and they showed low toxicity towards normal human liver cells. ICP-MS detection indicated that the copper complexes were accumulated in mitochondria. Mechanistic studies demonstrated that the copper complexes induced G0/G1 arrest and altered the expression of the related proteins of the cell cycle. All copper complexes reduced the mitochondrial membrane potential while increasing the intracellular ROS levels and the release of Ca²⁺. They also up-regulated Bax and down-regulated Bcl-2 expression levels, caused cytochrome c release and the activation of the caspase cascade, and induced mitochondrion-mediated apoptosis. Animal studies demonstrated that complex 1 suppressed tumor growth in a mouse xenograft model bearing BEL-7402 tumor cells.

Nanoparticles Functionalised with Re(I) Tricarbonyl Complexes for Cancer Theranostics

Globally, cancer is the second (to cardiovascular diseases) leading cause of death. Regardless of various efforts (i.e., finance, research, and workforce) to advance novel cancer theranostics (diagnosis and therapy), there have been few successful attempts towards ongoing clinical treatment options as a result of the complications posed by cancerous tumors. In recent years, the application of magnetic nanomedicine as theranostic devices has garnered enormous attention in cancer treatment research. Magnetic nanoparticles (MNPs) are capable of tuning the magnetic field in their environment, which positively impacts theranostic applications in nanomedicine significantly. MNPs are utilized as contrasting agents for cancer diagnosis, molecular imaging, hyperfusion region visualization, and T cell-based radiotherapy because of their interesting features of small size, high reactive surface area, target ability to cells, and functionalization capability. Radiolabelling of NPs is a powerful diagnostic approach in nuclear medicine imaging and therapy. The use of luminescent radioactive rhenium(I), 188/186Re, tricarbonyl complexes functionalised with magnetite Fe3O4 NPs in nanomedicine has improved the diagnosis and therapy of cancer tumors. This is because the combination of Re(I) with MNPs can improve low distribution and cell penetration into deeper tissues.

Synthesis and Catalytic Application of Two Mononuclear Complexes Bearing Diethylenetriamine Derivative Ligand

Two mononuclear zero-dimensional Ni(II) and Zn(II) complexes bearing diethylenetriamine derivative ligand, namely [NiL(CH₃COO)₂(H₂O)] (1) and [ZnL(CH₃COO)₂] (2) [L = N, N'-bis(2-hydroxybenzyl)diethylenetriamine], were synthesized under reflux conditions. The molecular composition and structure of the complexes were identified by IR, PXRD, elemental analyses, and single crystal X-ray diffraction. Complex 1 belongs to a monoclinic crystal system with the P2₁/n space group, and Complex 2 belongs to a monoclinic crystal system with the C2/c space group. The Henry reaction of nitromethane with aromatic aldehydes was explored with Complexes 1 and 2 as the catalyst. Results from the catalytic reaction revealed that the complexes displayed excellent catalytic activities under the optimized conditions and that the substrate scope of aromatic aldehydes could be extended to a certain extent. In addition, the possible catalytic mechanism of the Henry reaction was also deduced.

Influence of DMβCD on the Interaction of Copper(II) Complex of 6-Hydroxychromone-3-carbaldehyde-3-hydroxybenzoylhydrazine with ctDNA

The interaction mechanism between a scarcely soluble copper(II) complex of Cu(II)-6-hydroxychromone-3-carbaldehyde-(3'-hydroxy)benzoylhydrazone (CuCHz) in aqueous solution and its DMβCD complex was studied in the presence of ctDNA through spectroscopy and thermodynamic methods. The thermodynamic results indicate that the binding process of the CuCHz-DMβCD inclusion complex is a spontaneous process and the inclusion is enthalpy-driven. The binding constants of CuCHz and CuCHz-DMβCD with ctDNA are 2.69 × 10³ and 14.7 × 10³ L mol^-1, respectively. The stoichiometry of the complex is 1:1, and the determined thermodynamic indicates that the process of binding is spontaneous and entropy-driven. A competitive binding titration with ethidium bromide revealed that CuCHz efficiently displaces EB from the EB-DNA system. In addition to the thermal denaturation experiments and docking studies, we can confirm that the mode of binding of this complex to ctDNA is intercalation mode. The presence of DMβCD enhances the aqueous solubility of CuCHz; nevertheless, the cyclodextrin did not affect the interaction of CuCHz with ctDNA because the inclusion complex breaks down when it binds with ctDNA.