DNA interaction, cytotoxic and phototoxic properties of new water-soluble zinc (II) phthalocyanines

In this paper, we have synthesized water-soluble peripherally tetra and octa-({6-[3-(dimethylamino)phenoxylhexyl}oxy) groups substituted zinc (II) phthalocyanines (DM-C6-ZnQ and o-DM-C6-ZnQ). Also, we have investigated ct-DNA binding, supercoiled plasmid DNA cleavage properties of DM-C6-ZnQ and o-DM-C6-ZnQ by using spectrophotometric and electrophoretic methods. On the other hand, cytotoxic and phototoxic effects of DM-C6-ZnQ and o-DM-C6-ZnQ were examined using (3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay on human lung adenocarcinoma (A549) cell lines. In UV-Vis absorption studies, hypochromism was observed about 18% for DM-C6-ZnQ and 57% for o-DM-C6-ZnQ on addition of increasing concentrations of ct-DNA. The intrinsic binding constant (K-b) values of DM-C6-ZnQ and o-DM-C6-ZnQ were 3.82 (+/- 0.14) x 10(4) M-1 and 2.34 (+/- 0.05) x 10(5) M-1, respectively. The supercoiled plasmid DNA cleavage studies showed that DM-C6-ZnQ and o-DM-C6-ZnQ had no DNA damage actions in the dark. On the other hand, they caused DNA damage depending on the light dose. In the MIT assay, the compounds had low cytotoxic properties on A549 cell lines, but they showed significant phototoxic actions. These results reveal that the compounds interact with DNA and have phototoxic properties; it has been determined that they have the potential to be photosensitizing agents for photodynamic therapy.