In 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 37C and in 0.16 M NaCl. Theprotonation constant of curcumin was also determined to evaluate the competition of the ligand for themetal cations and Hþ. Speciation profiles obtained by potentiometric titrations show that in aqueoussolution a complexation occurs at 1:1 ligand-to-cations ratio. With the aim to define the coordinationsites of curcumin with these metal ions a mass spectrometry and UVeVis spectroscopy characterizationwas carried out. It was found that aluminum binds to the keto-enol moiety of curcumin, while iron bindsto the guaiacol (2-methoxyphenol) one. This unexpected experimental evidence was supported by a thorough computational study.

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

Beneduci, Amerigo;Corrente, Giuseppina Anna;Marino, Tiziana
;
Aiello, Donatella;Bartella, Lucia;Di Donna, Leonardo;Napoli, Anna;Russo, Nino;ROMEO, ISABELLA;Furia, Emilia
2019

Abstract

In 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 37C and in 0.16 M NaCl. Theprotonation constant of curcumin was also determined to evaluate the competition of the ligand for themetal cations and Hþ. Speciation profiles obtained by potentiometric titrations show that in aqueoussolution a complexation occurs at 1:1 ligand-to-cations ratio. With the aim to define the coordinationsites of curcumin with these metal ions a mass spectrometry and UVeVis spectroscopy characterizationwas carried out. It was found that aluminum binds to the keto-enol moiety of curcumin, while iron bindsto the guaiacol (2-methoxyphenol) one. This unexpected experimental evidence was supported by a thorough computational study.
DFT
Coordination sites
Stability constants
Aluminum curcumin complexes
Iron curcumin complexes
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Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/20.500.11770/295973
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