A mononuclear diketone-based oxido-vanadium(iv) complex: structure, DNA and BSA binding, molecular docking and anticancer activities against MCF-7, HPG-2, and HT-29 cell lines

Abstract

A mononuclear oxido-vanadium(IV) complex, [VO(L)₂], has been prepared from the reaction of dibenzoylmethane (HL) and VO(acac)₂ in a 2 : 1 molar ratio, and fully characterized using elemental analyses, molar conductivity, FT-IR, and electronic spectroscopy. The structure of this compound was also confirmed by single crystal X-ray diffraction. It was found that in the title complex, the metal coordination geometry is described as a distorted square pyramid. DNA binding activities of this complex were investigated using electronic absorption titration, competitive fluorescence titration and cyclic voltammetry studies. The obtained results showed groove binding of the complex to salmon sperm DNA accompanied with a partial insertion of the ligand between the base stacks of the DNA with a binding constant of 2.3 × 10³ M⁻¹. In addition, the interaction of the complex with bovine serum albumin (BSA) was studied using electronic absorption and fluorescence spectroscopies at different temperatures indicating a good affinity of the complex for BSA. These experimental results were confirmed by the results of molecular docking. Finally, the in vitro cytotoxicity properties of the synthesized complex against MCF-7, HPG-2 and HT-29 cell lines were evaluated and compared with those of the ligand (HL). It was found that complexation improved the anticancer activity significantly. IC₅₀ values for the V(IV) complex against MCF-7, HPG-2 and HT-29 cell lines were obtained as 7.8, 13.5 and 16.1 μM, respectively.