Issue 10, 2018

New curcumin-derived ligands and their affinity towards Ga3+, Fe3+ and Cu2+: spectroscopic studies on complex formation and stability in solution

Abstract

The metal complexing ability in solution of four substituted curcumin (CUR)-derived ligands K3T, originated by the insertion of the –CH2CH2COOtBu branch on the central atom of the diketonic moiety of CUR and related derivatives with variable meta and para substituents (OH, OMe, H, OCOCH3) on the peripheral aromatic rings, is examined. These molecules can act as new chelators with biological properties comparable to those of CUR but with improved stability. In fact, curcuminoids represent new perspectives for the development of novel therapeutic agents for several diseases including Alzheimer's disease. CUR showed neuroprotective properties, and a probable mechanism of its action is related to the complexation ability towards endogenous metal ions Fe3+ and Cu2+. K3T derivatives retain the solvent-dependent diketo–ketoenol tautomerism, with the prevalence of the diketonic form in aqueous solution. They show enhanced stability in simulated physiological conditions (phosphate buffered solution at pH = 7.4) compared to CUR, together with similar or even higher anti-proliferative activity against human colon carcinoma cells HCT116. The addition of the metal ion causes dissociation of the enolic proton creating chelate complexes and shift of the tautomeric equilibrium toward the keto–enol species. The formation of metal complexes was followed and confirmed by both NMR (using Ga3+ as a diamagnetic probe for Fe3+) and UV-visible spectroscopy. All the ligands showed high affinity for Fe3+ and Ga3+, forming M : L 1 : 2 species. In view of therapeutic applications, notable is the good affinity of K3T31, i.e. the ligand bearing only OH groups in para positions of the aromatic rings, for Cu2+, and the ability of the Cu : K3T31 1 : 1 complex to bind to DNA.

Graphical abstract: New curcumin-derived ligands and their affinity towards Ga3+, Fe3+ and Cu2+: spectroscopic studies on complex formation and stability in solution

Supplementary files

Article information

Article type
Paper
Submitted
30 Janv. 2018
Accepted
02 Marts 2018
First published
05 Marts 2018

New J. Chem., 2018,42, 7680-7690

New curcumin-derived ligands and their affinity towards Ga3+, Fe3+ and Cu2+: spectroscopic studies on complex formation and stability in solution

L. Rigamonti, G. Orteca, M. Asti, V. Basile, C. Imbriano, M. Saladini and E. Ferrari, New J. Chem., 2018, 42, 7680 DOI: 10.1039/C8NJ00535D

To request permission to reproduce material from this article, please go to the Copyright Clearance Center request page.

If you are an author contributing to an RSC publication, you do not need to request permission provided correct acknowledgement is given.

If you are the author of this article, you do not need to request permission to reproduce figures and diagrams provided correct acknowledgement is given. If you want to reproduce the whole article in a third-party publication (excluding your thesis/dissertation for which permission is not required) please go to the Copyright Clearance Center request page.

Read more about how to correctly acknowledge RSC content.

Social activity

Spotlight

Advertisements