Synthesis, structural characterization and in vitro cytotoxic evaluation of mixed Cu(II)/Co(II) levofloxacin–bipyridyl complexes

Abstract

This work features synthesis, structural characterization and biological evaluation of two Cu(II)/Co(II)–based complexes (1 and 2) synthesized from levofloxacin (lvXn) and bipyridyl ligands. The structural elucidation of complexes 1 and 2 was carried out by analytical, spectral (UV–vis, FTIR, EPR) and single crystal X–ray crystallographic techniques. The crystallographic details of complex 1 revealed a triclinic crystal system with P-1 space group and lattice parameters a = 10.32(7) Å, b = 11.75(8) Å, c = 14.85(9) Å, and α = 87.40°, β = 77.55°, γ = 66.26°. The DFT studies were performed to study the electronic structure and localization of HOMO and LUMO electron densities on the complexes. We have also performed comparative in vitro DNA/BSA binding studies of complexes 1 and 2 by multispectroscopic methods to evaluate the cytotoxic potential of synthesized complexes which revealed better binding potential of copper analogue. Furthermore, the cytotoxic assessment of copper analogue was examined on a panel of five human cancer cell lines employing SRB assay which revealed remarkably good and selective cytotoxic activity towards A498 (kidney), HeLa (cervical) and HepG2 (hepatoma) cancer cell lines.