In vitro antiproliferative effect of four ball-type phthalocyanines linked by t-butylcatechol and high singlet oxygen production

Abstract

Four ball-type phthalocyanines (H₂Pc, MgPc, CoPc, and ZnPc) containing 4-tert-butylcatechol substituents at alpha-positions were synthesized from 3,3′-(4-tert-butyl-1,2-phenylene)bis(oxy)diphthalonitrile. The structures were elucidated by elemental analysis and ultraviolet-visible, Fourier-transform infrared, proton nuclear magnetic resonance, and Maldi-Tof mass spectroscopies. The photophysicochemical properties of H₂Pc, MgPc, and ZnPc were investigated in dimethylsulphoxide. The fluorescence quantum yields (Φ_F), triplet state quantum yields (Φ_T), and singlet oxygen quantum yields (Φ_Δ) with respect to H₂Pc, MgPc and ZnPc were experimentally obtained. Furthermore, the degradation quantum yield (Φ_d) was evaluated for all complexes. Finally, the magnetic circular dichroism spectra of the four Pcs were obtained. Among these ball-type phthalocyanines, MgPc had the highest triplet lifetime and ZnPc had the highest singlet oxygen quantum yield. Moreover, the in vitro antiproliferative effect of ball-type phthalocyanines (H₂Pc, MgPc, CoPc, and ZnPc) was evaluated on MCF-7 cell line originated from luminal A breast cancer and MDA-MB-231 cell line originated from triple negative breast cancer. For this purpose, cell viability MTT (3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide) assay was used. For all compounds, 0.2, 0.4, 0.8, 1.6, 3.2, 6.4, 12.8, 25.6, 51.2, 102.4 µM concentrations were applied to both cell lines. There was a significant decrease in cell viability for MCF-7 and MDA-MB-231 cells (p < 0.05).

Graphical Abstract

Keywords:

• Ball-type phthalocyanines
• high singlet oxygen quantum yield
• MTT
• antiproliferative effect
• MCF-7
• MDA-MB-23

Acknowledgements

The authors are thankful to the Yildiz Technical University in Turkey, the University of Illinois at Urbana-Champaign in the USA, and Rhodes University in Grahamstone, South Africa. The authors would like to thank Prof. Kenneth S. Suslick for the synthesis of compounds. The authors are also thankful to Prof. Tebello Nyokong for the photophysical and photochemical measurements.

Disclosure statement

No potential conflict of interest was reported by the authors.

Additional information

Funding

This work was supported by Tubitak-BİDEB-2219 International Postdoctoral Research Scholarship Programme [Applying Number: 1059B191401081] in Turkey.