Synthesis, characterization, and antitumor activity of binuclear curcumin-metal(II) hydroxo complexes

Binuclear curcumin-M(II) (M, Cu, Zn, Cd) hydroxo complexes, obtained by the reaction of metal (II) nitrate and curcumin in a 1:2 mol ratio were characterized by elemental analysis, FTIR, UV, and mass spectroscopy. Mechanism of reaction was elucidated showing that curcumin catalyzes hydroxyl formation in the presence of the oxolating nitrate groups. Cytotoxic activities of curcumin alone and the three complexes against a panel of four cancer cell lines, MCF-7, HEPG2, Hela, and HCT-116, was investigated in vitro. Curcumin alone was found to be more effective as an anticancer agent compared to the metal-complexed curcumin.