Zinc coordination complexes as anticancer agents

Zinc, present in all forms of life, is an essential element for humans. It is one of the most abundant metals in our body. Because of its importance, any malfunctions of its homeostasis can lead to different disease states, also related to the development of cancer. On the other hand, several Zn complexes have been recognized for their biological activities principally for preventive effects on infectious diseases and for low toxicity. Among different applications in medicinal chemistry, zinc-based complexes have shown to be appealing as anticancer drugs with low toxicity or as photosensitizers in photodynamic therapy. Here we present an overview of Zn coordination complexes proposed in the last six years as anticancer agents, trying to find a correlation between their chemical features and biological activity, and to evidence the potential perspectives of their use. Despite the great amount of work done in this field, this is the first exhaustive review on antitumor zinc complexes, that might be of wide interest for the researchers in the design and synthesis of new antitumor zinc-based drugs alternative to platinum derivatives.