Preliminary spectroscopic studies of the interactions between 9-fluoro-5-alkyl-12(H)-quino[3,4-b][1,4]benzothiazine chloride and DNA.

Cancer treatment is one of the challenges of modern medicine. The advancement of new anticancer drugs requires a comprehensive understanding of their mechanism of action and structure-activity relationships. 9-fluoro-5-alkyl-12(H)-quino[3,4-b][1,4]benzothiazine chloride (Salt2) is a newly synthesized substance exhibiting promising anticancer activity. Deoxyribonucleic acid (DNA) is a macromolecule of high biological importance. DNA is essential for cellular development, including DNA replication, transcription and translation. Binding of small molecules to DNA can inhibit or modify cellular DNA function and induces cell death. In turn, it can allow to alleviate or control the disease. The objective of the research was to assess the interactions of a newly developed substance (Salt2) and calf thymus DNA (ctDNA) using UV-VIS, spectrofluorescence and circular dichroism spectroscopy. The UV-VIS and fluorescence analysis showed that Salt2 might form a strong, intercalative complex in the ground state with ctDNA. Due to the fact that Salt2 changes ctDNA structure it can be assumed, that Salt2 can effect on DNA replication, transcription and translation processes and inhibits or modifies cellular DNA function. The results obtained for the Salt2-ctDNA complex, not only encourage further research, but may also prove useful in determining binding to human cellular DNA.