Synthesis, characterization and comparative DNA interaction studies of new copper(II) and nickel(II) complexes containing mesalamine drug using molecular modeling and multispectroscopic methods

<div><p>Complexes of copper(II) and nickel(II) containing the drug mesalamine (5-ASA) have been synthesized and characterized by FT-IR, mass and UV–vis spectra, elemental analysis, and theoretical methods. The binding interactions between mesalamine and its Cu(II) and Ni(II) complexes with calf thymus DNA (ct-DNA) were investigated using absorption, fluorescence emission and circular dichroism (CD) spectroscopies, and viscosity measurements. Absorption spectra of 5-ASA, Cu(II) and Ni(II) complexes showed hypochromism. The calculated binding constants (<i>K</i>_b) obtained from UV–vis absorption studies were 1.27 × 10³, 1.6 × 10³, and 1.2 × 10⁴ M⁻¹ for 5-ASA, Cu(II) and Ni(II) complexes, respectively. The compounds induced detectable changes in the CD spectra of ct-DNA (B → A structural transition, B → C structural transition and stabilization of the right-handed B form, for mesalamine, Cu(II) and Ni(II) complexes, respectively). The competitive binding experiments with Hoechst 33258 indicated that 5-ASA and copper complex could interact as groove binders. Furthermore, Ni complex had no effect on the fluorescence intensity and peak position of MB-DNA system. Finally, the results obtained from experimental and molecular modeling showed that complexes bind to DNA via minor-groove binding.</p></div

Synthesis, characterization, molecular modeling, and DNA interaction studies of a Cu(II) complex containing drug of chronic hepatitis B: adefovir dipivoxil

<div><p>A new copper(II) complex [Cu(adefovir)₂Cl₂], where adefovir = adefovir dipivoxil drug, was synthesized and characterized by using different physicochemical methods. Binding interaction of this complex with calf thymus DNA (ct-DNA) has been investigated by multi-spectroscopic techniques and molecular modeling study. The complex displays significant binding properties of ct-DNA. The results of fluorescence and UV–vis absorption spectroscopy indicated that, this complex interacted with ct-DNA in a groove-binding mode, and the binding constant was 4.3(±0.2)  ×  10⁴ M⁻¹. The fluorimeteric studies showed that the reaction between the complex and ct-DNA is exothermic (Δ<i>H</i> = 73.91 kJ M⁻¹; Δ<i>S</i> = 357.83 J M⁻¹ K⁻¹). Furthermore, the complex induces detectable changes in the CD spectrum of ct-DNA and slightly increases its viscosity which verified the groove-binding mode. The molecular modeling results illustrated that the complex strongly binds to the groove of DNA by relative binding energy of the docked structure −5.74 kcal M⁻¹. All experimental and molecular modeling results showed that the Cu(II) complex binds to DNA by a groove-binding mode.</p></div

Human serum albumin interaction studies of a new copper(II) complex containing ceftobiprole drug using molecular modeling and multispectroscopic methods

<p>A copper(II) complex containing the ceftobiprole drug and 1,10-phenanthroline (phen) has been synthesized and characterized by UV–vis, FT-IR and mass spectra, and elemental analysis. The binding interaction between [Cu(cef)(phen)Cl₂] complex and human serum albumin (HSA) was investigated using absorption, fluorescence emission and circular dichroism spectroscopies, and molecular docking. Thermodynamic parameters (Δ<i>H</i> < 0 and Δ<i>S</i> < 0) indicated that the hydrogen bond and van der Waals interactions played main roles in the binding of complex [Cu(cef)(phen)Cl₂] to HSA. The results of CD and UV–vis spectroscopy showed that the binding of [Cu(cef)(phen)Cl₂] to HSA induces some conformational changes in HSA. Displacement experiments predicted that the binding of [Cu(cef)(phen)Cl₂] complex to HSA is located within domain III, Sudlow’s site 2, and these observations were substantiated by molecular docking studies.</p