Synthesis and Characterization of Juglone‐Derived cu (II), Mn (II) and Zn (II) Complexes and Investigation of Their Cytotoxic Activities Against Lung and Colon Cancer Cells in Vitro <i>and in Silico</i>

Three new Zn (II), Cu (II) and Mn (II) complexes have been synthesized from 5-hydroxy-1,4-naphthoquinone (HNQ). Elemental analysis, magnetic susceptibility, UV-Vis, IR and Mass spectrometry have all been used to explore the structural characterization of these compounds. When the electronic spectra of these compounds are examined, they correspond to π → π* transitions in the 261-262 nm range, n → π* transitions in the 316-354 nm range, and charge transfer transitions in the 417-423 nm range. Also, in vitro cytotoxic activities of both juglone ligand and its metal complexes against A549 lung cancer and HT-29 colon cancer cells have been investigated. The Mn (II)-Juglone complex showed better cytotoxic activity than juglone ligand and other metal complexes in both cell lines. Moreover, molecular docking analyses demonstrated that the Mn (II)-Juglone complex exhibited stronger binding interactions with both DNA and the anti-apoptotic protein Bcl-2 compared to the free Juglone ligand. Annexin V/PI double staining results using flow cytometry showed that there were more total apoptotic cells in the Mn (II)-Juglone complex-treated groups than in the ligand-treated groups in both cell lines. In addition, it was found that Cas-3 and Bax immunoreactivity increased significantly and Bcl-2 immunoreactivity decreased significantly in Mn (II)-Juglone complex-treated groups compared to the control and ligand groups.