Anticancer activity of novel silicon phthalocyanines against the colorectal adenocarcinoma cell line (DLD-1)

In this study, the DNA cleavage activities of a series of new silicon phthalocyanines were studied to measure their potential for cancer treatment. For this purpose, 2-(2,4,6-tris((dimethylamino)methyl)phenoxy)ethan-1-ol (2) and 2-(2-(2,4,6-tris((dimethylamino)methyl)phenoxy)ethoxy)ethan-1-ol (3) were synthesized and used for the preparation of axially di-substituted silicon phthalocyanines. The resulting phthalocyanines were quaternized in the presence of iodomethane. Characterization of all the newly synthesized compounds was carried out using several spectroscopic approaches including mass, UV-vis, FT-IR, and NMR spectroscopies. Plasmid DNA (pBR322) cleavage, topoisomerase enzyme activity and binding situation with calf thymus DNA (CT-DNA) of the new silicon phthalocyanines were measured using an agarose gel electrophoresis assay. 1-QSi exhibited remarkable cleavage activities on supercoiled plasmid DNA at all the studied concentrations. Compound 3-QSi displayed significant cleavage activities on supercoiled plasmid DNA only at 200 μg mL⁻¹. Besides, compound 3-QSi exhibited higher human topoisomerase I inhibition activity compared to compound 2-QSi. Moreover, all the compounds were screened for biological activities. The cytotoxicity and apoptosis activities were studied against DLD-1 colorectal cancer cell lines at different concentrations ranging from 6.25 to 100 μg mL⁻¹. The results indicated that the studied compounds can be utilized as anticarcinogenic agents.