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

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 oC as compared with 75, 50 and 25oC respectively. The chemical shifts of spectrum shows that the curcumin was strongly interact with Al (III).