Water-soluble Cu(II)-complexes of Schiff base amino acid derivatives as biological reagents and sufficient catalysts for oxidation reactions

Abstract

Two novel water-soluble Cu(II) complexes (Cu-PSA and Cu-PSL) are synthesized from easily accessible Schiff base amino acid ligands (HPSA and HPS), as sodium sulfonate salts, obtained from D,L-phenylalanine and D,L-leucine, respectively. Their chemical composition is confirmed using various spectroscopic analyses (NMR, UV–vis, IR and mass spectroscopies, CHN micro-analyses, conductivities, TGA, and magnetism). The effect of sodium sulfonate group (Na+ SO3− group) on the chemical behavior of both Cu-PSA and Cu-PSL complexes is studied catalytically and biologically. Catalytically, Cu-PSA and Cu-PSL exhibit high reactivity in the (ep)oxidation of 1,2-cyclooctene and benzyl alcohol in polar reaction media, (acetonitrile or water) at 80 °C, under homogeneous reaction condition. Biologically, the Cu-complexes and their ligands (HPSA and HPS) are tested for antimicrobial activity against some pathogens strains. Both Cu-complexes reveal higher performance than their corresponding ligands. Cu-PSA and Cu-PSL complexes are also examined for ctDNA-interaction, which studied using various techniques including spectroscopy, viscosity and gel-electrophoresis. Despite, their low lipophilicity due to the sodium sulfonate group (salting group), they show potentially high electrostatic interaction with ctDNA. The binding potential of these compounds is also investigated by molecular docking showing the role of the central metal ion (Cu2+) and the salting group in the ctDNA interaction. For anticancer reactivity, both ligands (HPSA, HPSL), and their complexes (Cu-PSA or Cu-PSL) are examined against hepatocellular carcinoma (HepG2) cell line, breast carcinoma (MCF7) cell line and colon carcinoma (HCT-116) cell line. The obtained results are encouraging and after optimization the Cu-complexes could be potentially anticancer drug candidates.