Coordination of the natural ligand lapachol to iron(II): synthesis, theoretical study and antiproliferative activity

Lapachol is a natural naphthoquinone known for having a variety of biological properties, and in recent years, it has been used in the synthesis of metal complexes with biological applications. This work reports on the synthesis, properties and antiproliferative activity of one new metal complex obtained by the reaction of the natural naphthoquinone lapachol with Fe(II). Characterizations by CHN elemental analysis, electrochemical and spectroscopic techniques (infrared, UV–Vis and luminescence) allowed to infer the coordination of two lapachol molecules to the metallic Fe(II) ion through the phenolic and carbonyl oxygens, as well as the presence of two water molecules completing the complex coordination sphere. Molecular modeling was in good agreement with the [Fe(Lap)2(H2O)2] $$\cdot$$ 2H2O complex structure proposed from the experimental data. Antiproliferative activity assay revealed the efficiency of the [Fe(Lap)2(H2O)2] $$\cdot$$ 2H2O complex against some human tumor cell lines, with lowest TGI (Total growth inhibition) value and higher selectivity index for the glioma tumor cell line (U251).