Glycosyl-curcuminoids as potential new chelating agents in iron overload chelation therapy

The iron(III) chelating ability of some glycosyl derivatives of curcuminoids is tested by means of UV, potentiometric and NMR studies. The pK(a) of the ligands and the stability constants of their Fe3+ and Ga3+ complexes are evaluated by UV spectroscopy. The only metal binding site of the ligand is the beta-dioxo moiety; the glycosyl moiety does not interact with the metal ion at acidic pH values but it helps to stabilise metal/ligand (1:2) complexes by means of hydrophilic interactions. By comparing the pFe(3+) of our ligands with those reported for other chelating agents we suggest using these molecules as pro-drugs in iron overload treatment. Some of the more water-soluble derivatives are also tested for their antioxidant properties in vitro in biological systems and proved to act as free-radical scavengers inhibiting the iron redox cycle, ((C) Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2004).