Synthesis, DNA binding and in vitro cytotoxicity studies of a mononuclear copper(II) complex containing N2S(thiolate)Cu core and 1,10-phenanthroline as a coligand

• Published in: Inorganica Chimica Acta Vol. 484; pp. 219 - 226
• Main Authors: Kumar, Manjuri, Parsekar, Sidhali Uday, Duraipandy, Natarajan, Kiran, Manikantan Syamala, Koley, Aditya P.
• Format: Journal Article
• Language: English
• Published: Elsevier B.V 01.01.2019
• Subjects: Apoptotic pathway; Cu(II) complex; Cytotoxicity and anticancer activity; DNA binding; EPR and electronic spectra; MTT assay; Cu(II) complex; EPR and electronic spectra; Apoptotic pathway; Cytotoxicity and anticancer activity; MTT assay; DNA binding
• ISSN: 0020-1693; 1873-3255
• DOI: 10.1016/j.ica.2018.09.044

A mononuclear Cu(II) complex containing the Schiff base N-(2-mercaptophenyl)-2′-pyridylmethylenimine and 1,10-phenantroline as the coligand shows remarkable cytotoxicity against human lung cancer A549 cells and epidermoid carcinoma A431 cell line but less toxic for normal L132 and HaCaT cells as evident from MTT assay. AO/PI dual staining assay for A549 cells suggests cell death via apoptosis for its anticancer activity. [Display omitted] •A mononuclear copper(II) complex shows intercalative DNA binding.•Shows significant cytotoxicity for the lung cancer A549 cell line.•Also shows significant cytotoxicity for the epidermoid carcinoma A431 cell line.•Possesses low toxicity toward L132 human lung embryonic normal cell line.•Remarkably low toxic toward human keratinocyte HaCaT normal cells.•AO/PI dual staining suggests cell death via apoptosis for the anticancer activity. We report the synthesis, characterization, spectroscopic properties, redox behavior and biological activities of the Cu(II) complex [Cu(pabt)(o-phen)](ClO4) (1), (Hpabt = N-(2-mercaptophenyl)-2′-pyridylmethylenimine, o-phen = 1,10-phenanthroline). The intense purple solution of 1 exhibits electronic spectrum with a strong LMCT band in the visible region mainly associated with S → Cu(II). It displays a four-line EPR multiplet due to the interaction of the unpaired electron with the central 63/65Cu nucleus (I = 3/2) with the Aiso value of 80 ± 1.5 G at RT suggesting its monomeric nature in solution. It shows irreversible electrochemical behavior suggesting the instability of the reduced Cu(I) species. It shows catechol oxidase activity and strong intercalative DNA binding as revealed from absorption, emission spectral and viscometric studies. It exhibits strong cytotoxicity against human lung cancer A549 and epidermoid carcinoma A431 cell lines as revealed from the MTT assay. The respective IC50 values are: 5.26 μM for A549 and 5.41 μM for A431. The compound is found to be less toxic for the L132 human lung embryonic normal cell line and least toxic for the human keratinocyte HaCaT normal cells. AO/PI dual staining assay with A549 and L132 cells suggests the compound induced cell death via apoptosis in A549 cells.