Schiff bases targeting an Sw-480 colorectal cell line: synthesis, characterization, ds-DNA binding and anticancer studies

Abstract

In present studies, six Schiff bases were prepared, characterized and evaluated for their anti-tumor activity against the colorectal cancer cell line SW-480. The test compounds were characterized by various physico-chemical techniques such as M. P., TLC, UV, FT-IR, elemental analysis, ¹H-NMR spectroscopy etc. and investigated for their non-covalent DNA binding potential. The electronic absorption and hydrodynamic studies expressed strong complementary evidence that the Schiff bases are binding between the narrow walls of the helical DNA grooves and were stabilized via electrostatic interactions through groove binding as the dominant binding mode. Moreover, these studies also revealed that the tested compound had significant non-covalent binding to chicken (ck) blood ds-DNA at blood pH (7.4) and body temperature 310 K: the calculated values of standard Gibbs free energy changes (ΔG = −RT ln K_f) for all compounds were negative which manifested the spontaneity of binding for all compounds. The cytotoxicity of the compounds was found through triplicate testing and the O. D. values were compared to find the percentage viability of the cells. The IC₅₀ values of the compounds were estimated through dose-dependent curves. HSB3, HSB4 and HSB1 showed relatively potent anti-cancer activity with IC₅₀ values of 7.0913 μg mL⁻¹, 17.1469 μg mL⁻¹ and 17.5254 μg mL⁻¹, respectively. The same compounds had also exhibited relatively better ds-DNA binding efficacy with binding constant values (9.1 × 10⁵, 3.5 × 10⁵ and 5.13 × 10⁴ respectively).