The Factors Effecting the Formation of Curcumin-Al (III) Complexes

Abstract

Curcumin has been recognized as a potential natural drug to treat the Alzheimer’s disease (AD) by chelating metal ions. In the present paper, curcumin–Al (III) [Cur - Al (III)] complexes were synthesized in aqueous solution and characterized by UV-visible spectroscopy. The formation of complexes between Al (III) and curcumin in acidic condition, by using citric acid as catalyst were studied. The complex molar ratio [Cur - Al (III] was found to be 2:1 in buffer phosphate of pH 1.0, 1.5, 2.0, 3.0, 3.5 and 4.0. The optimum pH for the complex [Cur - Al (III)] formation was at phosphate buffer of pH=2.5, at this pH the complex [Cur. - Al (III)] was more stable than the other pH values (throughout the absorbance calculation at 531nm). About 92% of Al (III) was chelated by curcumin at pH 2.5 as compared with 1.0, 1.5, 2.0, 3.0, 3.5 and 4.0 pH values. Curcumin complexes (at pH 2.5) were thermally stable at 100 o C as compared with 75, 50 and 25 o C respectively. The chemical shifts of spectrum shows that the curcumin was