Structural elucidation of a new binuclear copper(II)/phenanthroline/2-(2,4-dihydroxybenzoyl)benzoate complex by synchrotron radiation, DNA interaction and cytotoxicity against tumor cells

• Published in: Inorganic chemistry communications 2024-09, Vol.167, p.112670, Article 112670
• Main Authors: Montilla-Suárez, Jerica M., Loures dos Santos, Aline, de Araújo, Bianca, Rodrigues, Júlia H.V., Tenorio, Juan C., B. P. Soares, Milena, Silva, Valdenizia R., de S. Santos, Luciano, Bezerra, Daniel P., Taylor, Jason G., Correa, Rodrigo S.
• Format: Article
• Language: English
• Subjects: Binuclear; Copper complex; Crystal structure; Cytotoxicity assay; Hybrid system
• ISSN: 1387-7003; 1879-0259
• DOI: 10.1016/j.inoche.2024.112670

[Display omitted] •A novel binuclear copper(II) complex was prepared.•This complex was confirmed by Synchrotron X-ray diffraction (SXRD).•Complex/CT-DNA interaction presents Kb of 1.6 × 104 L.mol−1.•Cytotoxic assays against HCT116 and HepG2 cells were carried out.•The complex showed higher levels of activated caspase-3 and cleaved PARP. A novel binuclear copper(II)-based complex was obtained with 2-(2,4-dihydroxybenzoyl)benzoate (DBB) and 1,10-phenanthroline (phen) as chelate ligands (Complex 1). Characterization was performed by ultraviolet, visible and infrared spectroscopy, and Synchrotron X-ray diffraction (SXRD), confirming the chemical structure. The crystal structure presents each metal center of complex 1 with a distorted square pyramidal geometry. Such as observed, one metal ion shows of one DBB and one phen as bidentate, as well as one monodentate methanol at the axial position. Meanwhile, the other copper center is also formed by one DBB and phen as bidentate ligands, and an additional carboxylate of DBB as monodentate, making a bridge between the two nuclei of the complex. Alamar blue assays revealed that complex 1 is cytotoxic against HCT116 (human colon carcinoma), and HepG2 (human hepatocellular carcinoma) tumor cell lines, with IC50 values of 5 and 2.75 μg.mL−1, respectively. HCT116 cells treated with complex 1 showed higher levels of activated caspase-3 and cleaved PARP (Asp214), as well as higher DNA fragmentation.