Synthesis, characterization, cytotoxicity, DNA cleavage, and antimicrobial activity of lanthanide(III) complexes of a Schiff base ligand derived from glycylglycine and 4-nitrobenzaldehyde

Abstract

Lanthanide complexes of Eu(III), Gd(III), Nd(III), Sm(III), and Tb(III) with the Schiff base derived from glycylglycine and 4-nitrobenzaldehyde were synthesized and characterized by elemental analysis, mass, IR, electronic spectra, molar conductance, TGA, and powder XRD. The results show that the Schiff base ligand acts as a tridentate monobasic donor coordinating through the azomethine nitrogen, deprotonated peptide nitrogen, and carboxylato oxygen atoms. Thermal decomposition profiles are consistent with the proposed formulations. The powder XRD studies show that all the complexes are amorphous in nature. Antimicrobial studies indicate that these complexes exhibit more activity than the ligand itself. The DNA cleavage activity of the ligand and its complexes were assayed on Escherichia coli DNA using gel electrophoresis in the presence of H2O2. The result shows that the Eu(III) and Nd(III) complexes have completely cleaved the DNA. The anticancer activities of the complexes have also been studied towards human cervical cancer cell line (HeLa) and Colon Cancer Cells (HCT116) and it was found that the Eu(III) and Nd(III) complexes were more active than the corresponding Gd(III), Sm(III), Tb(III) complexes and the free ligand on both the cancer cells.