Four mononuclear platinum(II) complexes: synthesis, DNA/BSA binding, DNA cleavage and cytotoxicity

Probing the interaction of new and biologically active Pd(II) complex with DNA/BSA via joint experimental and computational studies along with thermodynamic, NLO, FMO and NBO analysis

Treatment with transition metal complexes is an efficient method to fight with cancer. Therefore, a new transition metal complex formulated as [Pd(1, 3-pn)(acac)]Cl (pn and acac stand for propylendiamine and acetylacetonate, respectively) was synthesized and analyzed using ¹H NMR, Fourier transform infrared, electronic absorption spectroscopy techniques as well as elemental analysis and conductivity measurement. The geometry optimization, frontier molecular orbital (FMO) analysis, molecular electrostatic potential (MEP), natural bond orbital (NBO) analysis and nonlinear optical (NLO) property were accomplished by density functional theory (DFT) at B3LYP level with 6-311G(d,p)/aug-cc-pVTZ-PP basis set. Preliminary determination of antitumor activity and lipophilicity of this metal complex was performed experimentally and the promising results were obtained. This encouraged us to study the interaction and binding mode/modes of this complex with DNA as the primary receptor for the chemotropic drugs and BSA as the transporter protein in the circulatory system. For this reason, the binding of newly made complex was assessed in-vitro under physiological state using experimental and in-silico molecular modeling studies. So, the CT-DNA binding study of this complex was explored using spectrofluorometric as well as spectrophotometric techniques, viscosity and gel electrophoresis experiments. Furthermore, fluorescence, UV-Vis, F[Formula: see text]rster resonance energy transfer and circular dichroism studies were carried out for BSA binding. The experimental and computational interaction studies showed that [Pd(1, 3-pn)(acac)]Cl complex binds to the minor groove of CT-DNA and interacts with BSA by van der Waals forces and hydrogen bond.

Anticancer activity and cell death mechanism of Pt(II) complexes: Their in vitro bio-transformation to Pt(II)-DNA adduct formation and BSA binding study by spectroscopic method

Pt(II) complex cis-[Pt(PEA)(OH₂)₂] X₂, C-2 (where, PEA = 2-Pyridylethylamine and X  = ClO₄^- or NO₃^-) was synthesized by hydrolysis of cis-[Pt(PEA)Cl₂] C-1. Glutathione (GSH) and DL-penicilamine (DL-pen) substituted complexes cis-[Pt(PEA)(GSH)],C-3 and cis-[Pt(PEA)DL-pen)]X C-4 were synthesized and characterized by spectroscopic methods. Kinetic studies were traced on complex C-2 with the thiols, GSH and DL-pen. Pt(II)-Sulfur adduct formation mechanisms of the substituted products C-3 and C-4 were established from the kinetic investigation. At pH 4.0, C-2 - thiols interactions follow two consecutive steps: the first step is dependent, and the second is independent of [thiol]. The association equilibrium constant (K_E), substitution rate constants for both steps (k₁ & k₂), and activation parameters (ΔH^‡ and ΔS^‡) have been assessed to propose the mechanism. Agarose gel electrophoresis mobilization pattern of DNA with complexes was performed to visualize the interaction nature. CT-DNA and BSA binding activities of the complexes have been executed by electronic, fluorescence spectroscopy, and viscometric titration methods. Evaluation of thermodynamic parameters (ΔH⁰, ΔS⁰, and ΔG⁰) from BSA binding constants was executed to propose the driving forces of interaction between these species. A molecular docking study was performed to evaluate the binding mode of complexes with BDNA strands. Anticancer activity of the complexes C-1 to C-4 was explored on both A549 and HEp-2 cell lines, compared with approved anticancer drugs cisplatin, carboplatin, and oxaliplatin. All these complexes were tested by NBT assay on normal cell line skeletal muscle cells (L6 myotubes) to observe the adverse effects compared to recognized anticancer medications. The ultimate aim is to explore the role of anticancer agents on cell death mechanism, which has been performed by flow-cytometer on HEp-2 cell lines.

Pt(II) and Au(III) complexes containing Schiff-base ligands: A promising source for antitumor treatment

The effective application of cisplatin in the clinic as an antitumor treatment has stimulated widespread interest in inorganic metal drugs. In particular, complexes containing the transition metals platinum and gold have attracted considerable attention due to their antitumor effects. The Pt(II) and Au(III) Schiff-base complexes are potential antitumor agents because of their remarkable biological activities and good stability, lipophilicity, and electroluminescent properties. These complexes act via various antitumor mechanisms that are unlike those of the classic platinum drugs, providing a feasible solution for improving the serious side effects caused by metal chemotherapy. In this review, promising antitumor agents based on Pt(II) and Au(III) complexes containing Schiff-base ligands, and their biological targets, including G-quadruplex DNA and thioredoxin reductase, are comprehensively summarized.

Selective cytotoxicity and antifungal properties of copper(II) and cobalt(II) complexes with imidazole-4-acetate anion or 1-allylimidazole

The physicochemical properties of metal complexes determine their potential applications as antitumor agents. In this study, the antitumor properties of mononuclear cobalt(II) and copper(II) coordination compounds (stoichiometry: [Co(iaa)₂(H₂O)₂]·H₂O (iaa = imidazole-4-acetate anion), [Co(1-allim)₆](NO₃)₂ (1-allim = 1-allylimidazole), [Cu(iaa)₂H₂O] and [Cu(1-allim)₄(NO₃)₂]) and their ligands have been evaluated on human lung carcinoma A549 cells and normal bronchial BEAS-2B cells. Designing the chemical structure of new antitumor agents the possible interactions with macromolecules such as DNA or proteins should be take into account. PCR gene tlr4 product served as DNA model, whereas lysozyme and phage-derived endolysin (both peptidoglycan degrading enzymes) were applied as protein/enzyme model. The interactions were analysed using PCR-HRM and circular dichroism, FT-IR, spectrophotometry, respectively. Additionally, the antimicrobial properties of the complexes at a non-cytotoxic concentration were analyzed against S. aureus, E. coli, P. aeruginosa and C. albicans strains. The results obtained in this study showed the selective cytotoxicity of metal complexes, mainly [Cu(1-allim)₄(NO₃)₂] towards tumor cells. From all tested compounds, only [Co(iaa)₂(H₂O)₂]^.H₂O non-covalently interacts with DNA. Cu(II) and Co(II) complexes did not affect the secondary conformation of tested proteins but modified the hydrolytic activity of enzymes (lysozyme and endolysin). Moreover, only [Co(iaa)₂(H₂O)₂]^.H₂O exhibited the antifungal properties. In conclusion, Co(II) and Cu(II) metal complexes bearing two imidazole-4-acetate ligands seemed to be promising antitumor and antifungal agents for future drug design and application.