Metal complexes of curcumin and curcumin derivatives for molecular imaging and anticancer therapy

•This review focuses on metal complexes of the natural, highly bioactive compound curcumin as well as on its derivatives for imaging and anticancer purposes.•It reveals that some metal complexes of curcumin and its derivatives, besides better solubility and higher stability, possess favorable biological activities.•There is a complex interaction of the ligand and ancillary ligands with various metal ions, which offers many possible applications, including the fine tuning of fluorescent properties and cytotoxicity.

Curcuminoids are highly bioactive, polyphenolic compounds derived from the roots of Curcuma longa. Among them, curcumin is the best known and shows potential against various diseases, such as cancer, neurodegenerative, autoimmune and infectious diseases combined with nontoxicity up to high dosages and fluorescent properties. Unfortunately, it has some disadvantages, e.g., a poor solubility in water or a rapid clearance, which prevent this natural compound from reaching its potential. There are many strategies to overcome these drawbacks, most notably the application of nanoparticulate, micellar or liposomal carriers. Various metals also have advantageous properties that can be used to mitigate the inherent disadvantages of curcumin, such as higher stability under physiological conditions and ease of detection in vivo. Metal complexes of curcumin and its derivatives broaden the potential applications in comparison to the parent ligand in modern imaging and anticancer strategies. A number of promising derivatives have been published so far. This review focuses on metal complexes of curcumin and its derivatives for imaging and anticancer application.