Synthesis, Structural Characterization, Biological Effects and Molecular Docking Study of New Schiff Base Ligands Containing Sulfonyl Units

Schiff bases containing sulfonyl units are important compounds because of their potential biological properties in the therapeutical field. In this study, three novel ligands (L1, L2, and L3) containing the sulfonyl groups, a derivative of Schiff base, were synthesized, and their molecular structures were characterized by FT-IR, ¹H-NMR, ¹³C NMR, and elemental analysis results. The antiproliferative activities of these Schiff base ligands were evaluated against human colon cancer (HT-29 and Caco-2) and mouse fibroblast (L929) cells by the 3-(4,5-dimethylthiazol-2-yl)−2,5-diphenyltetrazolium bromide (MTT) method. In addition, the antioxidant activities of these ligands were determined. Their potential activities against Peroxiredoxin 2 enzyme were assessed with molecular docking studies. When the spectral evaluation of the novel Schiff Base compounds (L1-3), the characteristic peaks and bands of target compounds were observed from ¹H NMR, ¹³C NMR, and FT-IR results. The elemental analysis results supported the structures of the characterized compounds. All compounds' DPPH radical scavenging effect was similar to rutin at the highest applied concentration. According to molecular docking results, it was determined that hydrogen bond and steric interactions played a role in the interaction of the compounds and Peroxiredoxin 2 protein. It was observed that there was a parallelism between molecular docking results and antioxidant activity results. As a result of in silico and in vitro studies, it was found that L2 compound was the most effective compound with −60.083 MolDock Score and −61.079 total energy data. It was observed that hydrogen bonding and steric interactions played a role in the interaction of the compounds with the protein. Each compound showed cytotoxic effects against human colon cancer cells with increasing doses but not against healthy cells. These results support the hope that these compounds can be used for therapeutic purposes.