Multi-stage screening to predict the specific anticancer activity of Ni(II) mixed-ligand complex on gastric cancer cells; biological activity, FTIR spectrum, DNA binding behavior and simulation studies

Exploring the binding properties of DNA/BSA and cytotoxicity studies with new terpyridine-ester-based metal complexes (M = Fe(III), Ni(II), Cu(II) and Ru(III)) - A comparative analysis

Many terpyridines and their metal complexes are known to exhibit remarkable potential for the interaction of biological targets. Notably, a subtle change in the structure of the ligand can influence these interactions significantly. In this regard, it would be very interesting to assess the binding affinity of functionalized molecules with DNA/BSA. In this work, a novel ester-based terpyridine (L) and the corresponding four metal complexes with Ni(II) (MC1), Cu(II) (MC2), Fe(III) (MC3) and Ru(III) (MC4) were prepared and structurally characterized using various spectroscopic and analytical techniques including the validation of molecular structures of ligand (L) and Ni(II)-Tpy complex (MC1). The EPR data demonstrate that MC1 is diamagnetic and other complexes (MC2-MC4) exhibit paramagnetic behavior. Additionally, the structures of ligands and metal complexes were determined using DFT studies and the same were utilized for the docking studies. Interestingly, MC3 and MC4 exhibit a predominant lowest binding energy of -9.62 Kcal/mol (with DNA) and -10.05 Kcal/mol (with BSA) respectively. The binding affinity of the ligand and its complexes with protein and DNA was evaluated by spectroscopic techniques. Notably, the cytotoxicity studies of L and MC1-MC4 were performed against the MCF-7 (human breast cancer) cell lines. The complex MC4 displayed great activity with an IC50 of 3.5 ± 1.75 μM among all synthesized compounds and comparable with cisplatin.

Silver(I) Complexes with Mefenamic Acid and Nitrogen Heterocyclic Ligands: Synthesis, Characterization, and Biological Evaluation

Four Ag(I) complexes with mefenamato and nitrogen heterocyclic ligands, [Ag(2-apy)(mef)]2 (1), [Ag(3-apy)(mef)] (2), [Ag2(tmpyz)(mef)2] (3), and {[Ag(4,4'-bipy)(mef)]2(CH3CN)1.5(H2O)2}n (4), (mef = mefenamato, 2-apy = 2-aminopyridine, 3-apy = 3-aminopyridine, tmpyz = 2,3,5,6-tetramethylpyrazine, 4,4'-bipy = 4,4'-bipyridine), were synthesized and characterized. The interactions of these complexes with BSA were investigated by fluorescence spectroscopy, which indicated that these complexes quench the fluorescence of BSA by a static mechanism. The fluorescence data also indicated that the complexes showed good affinity for BSA, and one binding site on BSA was suitable for the complexes. The in vitro cytotoxicity of the four complexes against human cancer cell lines (MCF-7, HepG-2, A549, and MDA-MB-468) and one normal cell line (HTR-8) was evaluated by the MTT assay. Complex 1 displayed high cytotoxic activity against A549 cells. Further studies revealed that complex 1 could enhance the intracellular levels of ROS (reactive oxygen species) in A549 cells, cause cell cycle arrest in the G0/G1 phase, and induce apoptosis in A549 cells in a dose-dependent manner.

Evaluation of the hydrogen-rich water alleviation potential on mercury toxicity in earthworms using ATR-FTIR and LC-ESI-MS/MS spectroscopy

The toxic effects of mercury in earthworms and the potential alleviation effect of hydrogen-rich water (HRW) using ATR-FTIR and LC-MS analysis methods were investigated. Different concentrations of mercury chloride (H1: 5 µg/mL, H2: 10 µg/mL, H3: 20 µg/mL, H4: 40 µg/mL, and C1: control) and mercury chloride prepared in hydrogen-rich water (H5: 5 µg/mL, H6: 10 µg/mL, H7: 20 µg/mL, H8: 40 µg/mL, and C2: control) were injected into earthworms. The changes and reductions in some bands representing proteins, lipids, and polysaccharides (3280 cm^-1, 2922 cm^-1, 2855 cm^-1, 1170 cm^-1, and 1047 cm^-1) showed that protective effects could occur in groups prepared with hydrogen-rich water. In the FTIR results, it was found that these bands in the H3 group were more affected and decreased by the influence of mercury on earthworms than the H7 group prepared with hydrogen. LC-MS analysis showed that the changes in some ions of the highest dose groups (H4 and H8) were different, and mercury caused oxidative DNA damage in earthworms. When the high-level application groups of mercury, i.e., H4 and H8 were compared with the controls, the ion exchange ([M + H] + ; m/z 283.1) representing the 8-Oxo-dG level in earthworms was higher in the H4 group than the H8 group. This reveals that HRW exhibited the potential ability to alleviate the toxic effects of mercury; however, a longer period of HRW treatment may be necessary to distinguish an obvious effect. The ATR-FTIR spectroscopy provided a rapid and precise method for monitoring the changes in biological tissues caused by a toxic compound at the molecular level.

OUP accepted manuscript

Fourteen new organotin(IV) complexes were successfully synthesized and characterized by elemental analyses, Fourier transform infrared spectroscopy (FT-IR), multinuclear (1H, 13C, and 119Sn) NMR spectroscopy, high-resolution mass spectrometry (HRMS), and X-ray single-crystal techniques. Crystallographic data showed that the complexes 1b, 2b, 3b, and 5b were macrocyclic compounds, 4b exhibited a one-dimensional spiral chain structure with distorted trigonal bipyramidal geometry, other complexes were centrosymmetric dimers, and there was an Sn2O2 four-membered ring in the middle of the molecule. In-vitro anticancer activity against the three human tumor cell lines NCI-H460, MCF-7, and HepG2 was studied, and the dibutyltin complex 5a is a more potent antitumor agent than other complexes and cisplatin. Cell apoptosis study of 5a with the highest activity on HepG2 cancer cell lines was done by flow cytometry; it was shown that the antitumor activity of 5a was related to apoptosis, and it inhibited proliferation by blocking cells in the G2/M phase. The single-cell gel electrophoresis assay results show that 5a induces DNA damage. 5a interacts with ct-DNA by intercalating the mode of interaction. UV-visible absorption spectrometry, fluorescence competitive, viscosity measurements, and gel electrophoresis results also support the intercalative mode of interaction for 5a with DNA.

Structural, theoretical and biological activity of mono and binuclear nickel(II) complexes with symmetrical and asymmetrical 4,6-diacetylresorcinol-dithiocarbazate ligands

The present work reports the synthesis and a structural study of two novel dithiocarbazate, the 4,6-diacetylresorcinol-S-benzyldithiocarbazate (H₃L¹) and the 4,6-diacetylresorcinol-bis(S-benzyldithiocarbazate) (H₄L²), and their Ni(II) complexes, [Ni(HL¹)(Py)] (1) and [Ni₂(L²)(PPh₃)₂] (2). Single crystal X-ray analyzes reveal mono and binuclear complexes and the metal centers with distorted square planar geometry. The analyses of the Hirshfeld surface and fingerprints plots revealed intermolecular contacts attributed to the H···H and C···H/H···C bonds. The Density Functional Theory (DFT), with the B3LYP functional and 6-311-G(d,p)/LanL2DZ basis sets, was employed to optimize the geometries of synthesized compounds. From the resulting geometries, the highest occupied and lowest unoccupied molecular orbital maps (HOMO-LUMO), orbital energy gap, electron localization function (ELF), electron density, natural bond orbital (NBO) analysis, and complexation of the ligands with Ni(II) were calculated supporting the experimental data. The ESI (+)-MS/MS data indicated the presence in solution of the characteristic fragmentation with the [H₃L¹]⁺ and [H₄L²]⁺ molecular ions for the ligands. The pharmacological potential of the dithiocarbazate ligands and their Ni(II) complexes were evaluated in vitro against MDA-MB-231 human breast cancer cells. A remarkable cytotoxic activity was observed, more evident for free ligands than complexes at low concentrations; however, this latter showed a better dose-response pattern, being more attractive in terms of pharmacokinetics and therapeutic window.