A binuclear Fe()/quinizarin complex as a structural model for anthracycline drugs binding to iron
The cis -[Fe(cyclam)Cl 2 ]Cl (cyclam = 1,4,8,11-tetraazacyclotetradecane) complex reacts with quinizarin (1,4-dihydroxy-9,10-anthraquinone, Qz), a biologically relevant molecule, yielding the binuclear complex [(Fe(cyclam)) 2 (Qz)]Cl(PF 6 ) 3 . This new compound was characterized by means of element...
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Published in | New journal of chemistry Vol. 46; no. 12; pp. 5515 - 5525 |
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Main Authors | , , , , , , , , , , , |
Format | Journal Article |
Language | English |
Published |
Cambridge
Royal Society of Chemistry
21.03.2022
|
Subjects | |
Online Access | Get full text |
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Summary: | The
cis
-[Fe(cyclam)Cl
2
]Cl (cyclam = 1,4,8,11-tetraazacyclotetradecane) complex reacts with quinizarin (1,4-dihydroxy-9,10-anthraquinone, Qz), a biologically relevant molecule, yielding the binuclear complex [(Fe(cyclam))
2
(Qz)]Cl(PF
6
)
3
. This new compound was characterized by means of elemental analysis, X-ray diffraction, cyclic voltammetry and spectroscopic techniques. Crystallographic and FTIR data indicated that the bridging ligand, quinizarin, is coordinated to the Fe
III
cation
via
the oxygen atoms of the carbonyl groups in the form of quinones. The effect of ancillary (cyclam) and bridging (Qz) ligands on the properties of the complex is reflected by the stabilization of the Fe
III
-Fe
III
configuration supported by Mössbauer spectroscopy. The efficiency of ROS generation and DNA cleavage activity for this binuclear complex, as well as for the free quinizarin ligand, were investigated. This metal complex exhibited very low photochemical activity; however, it revealed a great ability to cleave the DNA molecule in the presence of glutathione, which was associated with the production of ROS species. Thereafter, the cytotoxic activity of these compounds was evaluated using the MTS assay against human tumor cells, namely lung adenocarcinoma (A549) and prostate carcinoma (LNCaP clone FGC), and against normal fibroblasts (L929). Our findings indicated low cytotoxic effects in general, where only a slight reduction in A549 and L929 cell viability was observed after light irradiation. Despite the lack of any significant biological activity, this binuclear compound validates
in vitro
the essential role of metal binding to an anthracycline-like moiety in the generation of ROS. The latter may be responsible for some of the cardiotoxicity reported for anthracycline-based drugs.
Quinizarin, an anthracyclin-like compound, was used to prepare a binuclear complex, [(Fe(cyclam))
2
Qz]Cl(PF
6
)
3
, which showed damage to DNA with glutathione. This mimic of anthracyclin drugs might explain undesired side effects of these compounds. |
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Bibliography: | Electronic supplementary information (ESI) available. CCDC For ESI and crystallographic data in CIF or other electronic format see DOI 2005420 10.1039/d1nj04087a |
ISSN: | 1144-0546 1369-9261 |
DOI: | 10.1039/d1nj04087a |