Exploring novel NH-form resorcinol-based schiff base and its metal complexes: Synthesis, characterization, cytotoxic activity, molecular docking and ADME studies

The research investigates the cytotoxic effects of the stable NH-form of a resorcinol-based Schiff base (HL) and its metal complexes (Zn(II), Cd(II), Cu(II), Ni(II)) on MCF-7 breast cancer cells. The structural characterization was conducted utilizing diverse analytical techniques, including mass spectrometry, elemental analysis, molar conductance, magnetic moment, UV-Vis, IR and ESR. The crystalline state analysis of HL through X-ray crystallography disclosed a hybrid structure comprising two canonical forms, specifically the quinoid and zwitterion, that contribute to resonance and diverse interactions, resulting in the development of a three-dimensional form. NMR, IR and ESR analyses showed that the HL was bidentate, using the oxygen of the hydroxyl and the nitrogen atom of azomethine, bonded to the metal center during complexation. The study explored the cytotoxic effects of HL and the various metal complexes on MCF-7 human breast cancer cells. All complexes display significant cytotoxicity (IC₅₀ < 38.37 μM). The activity of the complexes was greater than that of the free ligand, with the Cu(II) complex followed by Zn(II) demonstrated superior cytotoxicity compared to Cd(II), and Ni(II) complexes. Notably, the Cu(II) and Zn(II) complex exhibited approximately 13.2 and 12.9 times greater cytotoxicity than the 5-F Uracil (5-FU) cancer drug. An MTT assay corroborated the antiproliferative activity. The molecular docking study has been performed for all compounds with the aromatase cytochrome P450 receptor protein associated with breast cancer (PDB code = 3eqm). ADME drug likeness model has been done.