Aspects of 2-acetyl-1,3-cyclopentanedione as a chromium(III) chelating agent: nutritional implications
2003
Blanco, C. | Rojas, A. | Gomez, M. | Ronda, F. | Caballero, P.
The chemistry of 2-acetyl-1,3-cycloalkanediones has acquired increased applied importance because of the great number of applications in the agroalimentary industry. The keto-enol ratios and equilibrium constants for proton reactions of 2-acetyl-1,3-cyclopentanedione have been determined in solution using nuclear magnetic resonance and spectrophotometric methods. Chromium(III) is an essential nutrient and it seems that high chromium supplementation improves glucose tolerance. Chromium chelates have been shown to have a significant beneficial effect on metal status by increasing metal bioavailability in human diets. The composition and log beta-value of the complex formed in aqueous solution by chromium(III) with the ligand mentioned above have been determined. A detailed reaction scheme is proposed for the 1:1 chelation process. The kinetic data are consistent with a mechanism in which the mono-enol tautomer of the ligand reacts with both metallic species, the fully hydrated metal ion and the Cr(OH)2+. The results are discussed in the light of previous work.
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