Non-aggregated axially disubstituted silicon phthalocyanines: Synthesis, DNA cleavage and in vitro cytotoxic/phototoxic anticancer activities against SH-SY5Y cell line

Abstract

In this paper, axially {6-[3-(dimethylamino)phenoxy]hexyl}oxy and {6-[3-(diethylamino)phenoxy]hexyl}oxy groups substituted silicon phthalocyanines were synthesized by reaction of SiPcCl2 with 6-[3-(dimethylamino)phenoxy]hexan-1-ol and 6-[3-(diethylamino)phenoxy]hexan-1-ol in the presence of NaH in toluene. The identity of silicon phthalocyanines was confirmed by 1H NMR, 13C NMR, FT-IR, UV–Vis and mass spectrometry. The aggregation behaviors of the compounds were examined in different solvents and concentrations in DMSO. In all studied solvents and concentrations, the compounds were non-aggregated. These compounds have been screened for DNA cleavage using agarose gel electrophoresis and cytotoxic/phototoxic effects against human neuroblastoma cell line (SH-SY5Y) using MTT assay. The results showed that the compounds (1a and 2a) cleaved significantly supercoiled plasmid DNA in a concentration-dependent fashion with irradiation. The compounds (1a and 2a) exhibited low dark toxicity but excellent phototoxicity with IC50 values 0.56 and 4.46 μM, respectively toward SH-SY5Y cell line. The finding highlights that these compounds presented great potential for photodynamic therapy.