abstract
With many metal-based drugs extensively used today in the treatment of cancer, attention has focused on the development of new coordination compounds with antitumor activity with europium(III) complexes recently introduced as novel anticancer drugs. The aim of this work is to design new Eu(III) complexes with gallic acid, an antioxida'nt phenolic compound. Gallic acid was chosen because it shows anticancer activity without harming health cells. As antioxidant, it helps to protect human cells against oxidative damage that implicated in DNA damage, cancer, and accelerated cell aging. In this work, the formation of binary and ternary complexes of Eu(III) with gallic acid, primary ligand, and amino acids alanine, leucine, isoleucine, and tryptophan was studied by glass electrode potentiometry in aqueous solution containing 0.1 M NaNO3 at (298.2 +/- 0.1) K. Their overall stability constants were evaluated and the concentration distributions of the complex species in solution were calculated. The protonation constants of gallic acid and amino acids were also determined at our experimental conditions and compared with those predicted by using conductor-like screening model for realistic solvation (COSMO-RS) model. The geometries of Eu(III)-gallic acid complexes were characterized by the density functional theory (DFT). The spectroscopic UV-visible and photoluminescence measurements are carried out to confirm the formation of Eu(III)-gallic acid complexes in aqueous solutions. (C) 2016 Elsevier Inc. All rights reserved.
keywords
INDUCED OXIDATIVE STRESS; RARE-EARTH COMPLEXES; GALLIC ACID; COSMO-RS; COORDINATION-COMPLEXES; PELTIPHYLLUM-PELTATUM; EQUILIBRIUM-CONSTANTS; LANTHANIDE COMPLEXES; STABILITY-CONSTANTS; ANTICANCER DRUGS
subject category
Biochemistry & Molecular Biology; Chemistry
authors
Taha, M; Khan, I; Coutinho, JAP
our authors
Imran Khan
Post-Doc Fellowship
Mohamed Taha Ahmed Amin
Post-doc Fellowshipacknowledgements
This work was financed by national funding from Fundacao para a Ciencia e a Tecnologia (FCT, Portugal), European Union, QREN, FEDER and COMPETE for funding the CICECO (project PEst-C/CTM/LA0011/2013), QOPNA (project PEst-C/QUI/UI0062/2013) and LSRE/LCM (project PEst-C/EQB/LA0020/2013). M. Taha and I. Khan acknowledge FCT for the postdoctoral grants SFRH/BPD/78441/2011 and SFRH/BPD/76850/2011, respectively.