Dataset Information

Synthesis, Characterization, Crystal Structure, DNA and HSA Interactions, and Anticancer Activity of a Mononuclear Cu(II) Complex with a Schiff Base Ligand Containing a Thiadiazoline Moiety.

ABSTRACT: A mononuclear Cu(II) complex [Cu(HL)(o-phen)]·H₂O (1) [H₃L =, o-phen = 1,10-phenanthroline] was isolated from methanol, and its X-ray single-crystal structure was determined. Frozen glass X-band EPR of 1 in dimethylformamide (DMF) at LNT showed a spectrum that is characteristic of a monomeric tetragonal character with g _∥ = 2.164, g _⊥ = 2.087, A _∥ = 19.08 mT, and A _⊥ ≤ 4 mT. Electronic spectroscopic studies using calf thymus DNA (CT-DNA) showed strong binding affinity of 1 as reflected from its intrinsic binding constant (K _b) value of 2.85 × 10⁵ M^-1. Competitive behavior of 1 with ethidium bromide (EB) displayed intercalative binding of DNA (K _app = 1.3 × 10⁶ M^-1). The compound displayed significant oxidative cleavage of pUC19 DNA. The interaction between HSA and complex 1 was examined by employing fluorescence and electronic absorption spectroscopic experiments. The secondary and tertiary structures of HSA were found to be altered as suggested by three-dimensional (3D) fluorescence experiments. The affinity of 1 to bind to HSA was found to be strong as indicated from its value of the binding constant (K _a = 2.89 × 10⁵ M^-1). Intrinsic fluorescence of the protein was found to be reduced through a mechanism of static quenching as suggested from the k _q (2.01 × 10¹³ M^-1 s^-1) value, the bimolecular quenching constant. The Förster resonance energy transfer (FRET) process may also be accounted for such a high k _q value. The r value (2.85 nm) calculated from FRET theory suggested that the distance between complex 1 (acceptor) and HSA (donor) is quite close. Complex 1 primarily bound to HSA in subdomain IIA as suggested by molecular docking studies. IC₅₀ values (0.80 and 0.43 μM, respectively) obtained from the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay with HeLa and MCF7 cells suggested remarkable in vitro anticancer activity of 1. Nuclear dual staining assays revealed that cell death occurred via apoptosis in HeLa cells and reactive oxygen species (ROS) accumulation caused apoptosis induction. On treatment with a 5 μM dose of 1 in HeLa cells, the cell population significantly increased in the G2/M phase, while it was decreased in G0/G1 and S phases as compared to the control, clearly indicating G2/M phase arrest.

SUBMITTER: Parsekar SU

PROVIDER: S-EPMC8792924 | biostudies-literature |

REPOSITORIES: biostudies-literature

ACCESS DATA

Similar Datasets

Project description:New Co(II), Ni(II), and Cu(II) complexes were synthesized with the Schiff base ligand obtained by the condensation of sulfathiazole with salicylaldehyde. Their characterization was performed by elemental analysis, molar conductance, spectroscopic techniques (IR, diffuse reflectance and UV-Vis-NIR), magnetic moments, thermal analysis, and calorimetry (thermogravimetry/derivative thermogravimetry/differential scanning calorimetry), while their morphological and crystal systems were explained on the basis of powder X-ray diffraction results. The IR data indicated that the Schiff base ligand is tridentate coordinated to the metallic ion with two N atoms from azomethine group and thiazole ring and one O atom from phenolic group. The composition of the complexes was found to be of the [ML2]∙nH2O (M = Co, n = 1.5 (1); M = Ni, n = 1 (2); M = Cu, n = 4.5 (3)) type, having an octahedral geometry for the Co(II) and Ni(II) complexes and a tetragonally distorted octahedral geometry for the Cu(II) complex. The presence of lattice water molecules was confirmed by thermal analysis. XRD analysis evidenced the polycrystalline nature of the powders, with a monoclinic structure. The unit cell volume of the complexes was found to increase in the order of (2) < (1) < (3). SEM evidenced hard agglomerates with micrometric-range sizes for all the investigated samples (ligand and complexes). EDS analysis showed that the N:S and N:M atomic ratios were close to the theoretical ones (1.5 and 6.0, respectively). The geometric and electronic structures of the Schiff base ligand 4-((2-hydroxybenzylidene) amino)-N-(thiazol-2-yl) benzenesulfonamide (HL) was computationally investigated by the density functional theory (DFT) method. The predictive molecular properties of the chemical reactivity of the HL and Cu(II) complex were determined by a DFT calculation. The Schiff base and its metal complexes were tested against some bacterial strains (Escherichia coli, Pseudomonas aeruginosa, Staphylococcus aureus, and Bacillus subtilis). The results indicated that the antibacterial activity of all metal complexes is better than that of the Schiff base.

Project description:A new family of dicopper(I) complexes [CuI2RL](X)2 (R=H, 1X, R=tBu, 2X and R=NO2, 3X, X=CF3SO3, ClO4, SbF6, or BArF, BArF=[B{3,5-(CF3)2C6H3}4]-), where RL is a Schiff-base ligand containing two tridentate binding sites linked by a xylyl spacer, has been prepared and characterized, and its reaction with O2 has been studied. The complexes were designed with the aim of reproducing structural aspects of the active site of type 3 dicopper proteins; they contain two three-coordinate copper sites and a rather flexible podand ligand backbone. The solid-state structures of 1ClO4, 2CF3SO3, 2ClO4, and 3BArF.CH3CN have been established by single-crystal X-ray diffraction analysis. 1ClO4 adopts a polymeric structure in the solid state while 2CF3SO3, 2ClO4, and 3BArF.CH3CN are monomeric. The complexes have been studied in solution by means of 1H and 19F NMR spectroscopy, which put forward the presence of dynamic processes. 1-3BArF and 1-3CF3SO3 in acetone react rapidly with O2 to generate metaestable [CuIII2(mu-O)2(RL)]2+ 1-3(O2) and [CuIII2(mu-O)2(CF3SO3)(RL)]+ 1-3(O2)(CF3SO3) species, respectively, that have been characterized by UV-vis spectroscopy and resonance Raman analysis. Instead, reaction of 1-3BArF with O2 in CH2Cl2 results in intermolecular O2 binding. DFT methods have been used to study the chemical identities and structural parameters of the O2 adducts, and the relative stability of the CuIII2(mu-O)2 form with respect to the CuII2(mu-eta2:eta2-O2) isomer. The reaction of 1X, X = CF3SO3 and BArF, with O2 in acetone has been studied by stopped-flow UV-vis exhibiting an unexpected very fast reaction rate (k=3.82(4)x10(3) M-1 s-1, DeltaH=4.9+/-0.5 kJ.mol-1, DeltaS=-148+/-5 J.K-1.mol-1), nearly 3 orders of magnitude faster than in the parent [CuI2(m-XYLMeAN)]2+. Thermal decomposition of 1-3(O2) does not result in aromatic hydroxylation. The mechanism and kinetics of O2 binding to 1X (X=CF3SO3 and BArF) are discussed and compared with those associated with selected examples of reported models of O2-processing copper proteins. A synergistic role of the copper ions in O2 binding and activation is clearly established from this analysis.

Dataset Information

Synthesis, Characterization, Crystal Structure, DNA and HSA Interactions, and Anticancer Activity of a Mononuclear Cu(II) Complex with a Schiff Base Ligand Containing a Thiadiazoline Moiety.

Similar Datasets

OmicsDI is part of the ELIXIR infrastructure