2-Acetyl-1,3-cyclopentanedione–oxovanadium(IV) complexes. Acidity and implications for gastrointestinal absorption

• Published in: Food and chemical toxicology 2007-02, Vol.45 (2), p.322-327
• Main Authors: Rojas, Antonio, Blanco, Carlos A., Ronda, Felicidad, Gomez, Manuel, Caballero, Pedro A.
• Format: Article
• Language: English
• Subjects: acute toxicity; animal models; Animals; Biological and medical sciences; cartilage; Chelating Agents; Chelation; chicken meat; chondroitin sulfate; collagen; Cyclopentanes - chemistry; Cyclopentanes - pharmacokinetics; dietary exposure; dosage; Electron Spin Resonance Spectroscopy; females; histopathology; hyaluronic acid; Hydrogen-Ion Concentration; Intestinal Absorption - drug effects; Intestinal tract; Kinetics; lesions (animal); males; Medical sciences; Oxovanadium(IV); rats; signs and symptoms (animals and humans); Structure-Activity Relationship; subchronic toxicity; Toxicology; Vanadates - chemistry; Vanadates - pharmacokinetics; Vanadium Compounds - chemistry; Vanadium Compounds - pharmacokinetics; β-triketone
• ISSN: 0278-6915; 1873-6351
• DOI: 10.1016/j.fct.2006.08.023

Since vanadyl sulphate has demonstrated insulin-like effects on glucose metabolism in animal and human trials, and organic vanadium complexes are better absorbed by the intestinal tract than vanadyl species, in this work the complexation of oxovanadium(IV) with 2-acetyl-1,3-cyclopentanedione is studied. Kinetic and equilibria in aqueous 1:1 chelation are investigated spectrophotometrically in aqueous solution at 25 °C. The mechanism proposed to account for the kinetic data involves a reversible pathway where VO +2 reacts with the enolate ion of the ligand. From calculated kinetic and thermodynamic parameters, it can be expected that the rates between final and initial monocharged complex concentration could help a better control of the absorption through the lipophilic membranes in the intestinal tract.