M. Borsari, E. Ferrari, R. Grandi
Jan 30, 2002
Citations
2
Influential Citations
167
Citations
Quality indicators
Journal
Inorganica Chimica Acta
Abstract
The pKa values of curcumin and diacetylcurcumin are, here doubtless, determined by means of spectroscopic and potentiometric measurements, and the enolic proton is the more acidic one. The interaction of Fe 3 + with curcumin and diacetylcurcumin, in water/methanol 1:1 solution, leads to the formation of the complex species [FeH2CU(OH)2] and [FeDCU(OH)2 ]( H 2CU and DCU=curcumin or diacetylcurcumin monoanion, respectively) which prevails near pH 7. At more basic condition the prevailing species are [FeH2CU(OH)3] − and [FeDCU(OH)3] − , which prevent metal hydroxide precipitation. 1 H NMR data state that the dissociated -diketo moiety of the ligands is involved in metal chelation. The pKa value of the deprotonation reaction is strongly anticipated by the metal ion, as shown by UV spectral data. The stability constants, evaluated from potentiometric data, are near to that of desferrioxamine, which is, by now, the only iron-chelating agent for clinical use. © 2002 Elsevier Science B.V. All rights reserved.