Synthesis, characterization, DNA/BSA binding and cytotoxicity studies of Mononuclear Cu(II) and V(IV) complexes of Mannich bases derived from Lawsone

Abstract

A series of new mononuclear copper complexes (1–5) and a vanadium complex (6) were synthesized using bidentate Mannich base ligands derived from bioactive molecule Lawsone. The structure of these new molecules/complexes (1–6) were characterized by various spectroscopic techniques such as UV-Vis, FT-IR, EPR, and ESI-MS. The structure of complex 1 was also confirmed by single crystal X-ray diffraction analysis, which revealed that complexes containing copper atom has slightly distorted square planar geometry. Computational studies were carried out for the synthesized compounds (1–6) using the DFT method with B3LYP/6–311 G (d, p) and LanL2DZ basis sets to assess the bond length, bond angle, HOMO, and LUMO energy gap (∆E). The CT-DNA and BSA binding (protein binding affinity) studies revealed that complex 4 exhibited the highest DNA binding affinity and complexes 5 and 6 exhibited the highest protein binding affinity. The cytotoxic activity of complexes 3–6 was evaluated using MTT assay along with the apoptosis assessment (AO/EB staining) against HepG2 (human liver carcinoma cell line). Furthermore, the data revealed that all the complexes 3–6 displayed very good anticancer activity with IC50 values in the range of 5.46–2.71 µM which is comparable with that of standard anticancer drug.