Anti-oxidant activity of hydroxy(thio)pyrone iron-chelators

The hydroxypyrones and related compounds have been widely investigated for medicinal applications. Although their interest has been mostly associated with their metal chelating role for mobilization of undesirable excess metal ion, the anti-oxidant activity is also a key feature. From these two perspectives, maltol, 3-hydroxy-2-methyl-4-pyrone, and its O,S-donor analogue, thiomaltol, have been investigated and the results are described herein. In particular, these compounds have been studied in solution, for the iron-complexation ability and electrochemical behaviour of the complexes, as well as for their anti-oxidant properties, namely in terms of hydroxyl radical scavenging activity and inhibition of lipid peroxidation. The results revealed that both the compounds are good iron chelators and are able to prevent the redox cycling of iron; they both present high activity as hydroxyl radical scavengers, although maltol evidences further anti-oxidant properties because it is a considerably stronger inhibitor of the liposome peroxidation.