Insight on the chelation of aluminum(III) and iron(III) by curcumin in aqueous solution

Publication date: 15 December 2019Source: Journal of Molecular Liquids, Volume 296Author(s): Amerigo Beneduci, Giuseppina Anna Corrente, Tiziana Marino, Donatella Aiello, Lucia Bartella, Leonardo Di Donna, Anna Napoli, Nino Russo, Isabella Romeo, Emilia FuriaAbstractIn this work we have studied the complexation of curcumin (HCur, 1,7-bis-(4-hydroxy-3-methoxyphenyl)-1,6-heptadiene-3,5-dione) with Al(III) and Fe(III) at 37 °C and in 0.16 M NaCl. The protonation constant of curcumin was also determined to evaluate the competition of the ligand for the metal cations and H+. Speciation profiles obtained by potentiometric titrations show that in aqueous solution a complexation occurs at 1:1 ligand-to-cations ratio. With the aim to define the coordination sites of curcumin with these metal ions a mass spectrometry and UV–Vis spectroscopy characterization was carried out. It was found that aluminum binds to the keto-enol moiety of curcumin, while iron binds to the guaiacol (2-methoxyphenol) one. This unexpected experimental evidence was supported by a thorough computational study.Graphical abstract
Source: Journal of Molecular Liquids - Category: Molecular Biology Source Type: research