Recent advances in therapeutical applications of the versatile hydroxypyridinone chelators

Hydroxypyridinones (HOPOs) are excellent class of chelators that have been gaining attention in the field of pharmaceutical drugs by their high chelating efficacy and specificity with different metal ions. Among all the metal ions, they exhibit a high binding affinity towards iron (III) and are clinically used as iron chelators nowadays. The HOPO family has different isomers, out of which 3,4-HOPO possesses applicability for designing drugs. The effect of methyl substitution on different positions of pyridinone ring also plays an essential role in deciding the pM values, thus describing the metal affinity. Several metal ions like Fe, Al, Cu, Zn, and some actinides are found to exhibit good chelation efficacy with HOPOs. In terms of denticity, there are various forms of HOPO. Among these, discussion on bidentate, tetradentate, hexadentate, octadentate, and dendrimers will be done here. This review systematically summarizes the various literature reports on the design and pharmacological activities of the newly developed HOPOs and their derivatives, including antibiotics, anticancer, and antineurodegeneratives.