Cytotoxicity studies, DNA interaction and protein binding of new Al (III), Ga (III) and In (III) complexes with 5‐hydroxyflavone

Abstract

We report the synthesis and characterization of three new complexes of the natural flavonoid 5‐hydroxyflavone (primuletin) and Al (III), Ga (III), In (III), respectively. The physico‐chemical properties and structural features of these three novel compounds have been investigated by elemental and thermogravimetric analysis, molar conductance and several spectroscopic techniques, including FT‐IR, UV–Vis and mass spectra. Based on the experimental data, the general chemical formula of the complexes is [M (C 15 H 9 O 3 ) 3 ] · n H 2 O, where M is the cation and n = 2 for Al (III), n = 0 for Ga (III), n = 1, for In (III); each one of the three 5‐hydoxyflavone molecules acts as a monoanionic bidentate chelate ligand in the complexes. DFT calculations further sustain the proposed structures of the complexes. Cytotoxicity was studied using MTS assay on cervical, breast, colon and ovary adenocarcinoma cell lines. The central metal ions exert cytotoxic effects in a disparate manner: Al (III) enhances, while Ga (III) and In (III) decrease the cytotoxicity of the ligand. As a means to investigate the mechanism underlying the cytotoxic effects of the complexes, interactions with calf thymus DNA, human serum albumin and transferrin were also carried out.