Cobalt (II) complexes with N-methyl thio semicarbazide Schiff bases: Synthesis, spectroscopic investigation, cytotoxicity, DNA binding and incision, anti-bacterial and anti-fungal studies

Abstract

• Three Schiff bases and its Co (II) complexes have been prepared and characterized spectroscopically. • Complexes were studied for their cytotoxic activity against HeLa and MCF7 cell lines. • DNA Binding and Incision affinity of the complexes have been evaluated. • Antimicrobial activity of the complexes against two gram-positive and two gram-negative strains and two fungal strains was also investigated. • Complexes showed potent results in all biological aspects. Three Co(II) complexes [Co(L 1 ) (I), [Co(L 2 ) H 2 O] II), and [Co(L 3 ) H 2 O] ](III), where L 1 H is 2-(2-Hydroxy-5-Bromo Benzylidine) Hydrazine N-Methyl Carbo-Thioamide, L 2 H is 2-(2-Hydroxy-5-Chloro Benzylidine) Hydrazine N-Methyl Carbo-Thioamide and L 3 H is 2-(2-Hydroxy-Phenylethylidine) Hydrazine N-Methyl Carbo-Thioamide were synthesized and spectroscopically characterized using FT-IR, UV-Drs, 1 H NMR, 13 C NMR, ESI Mass, TGA, Magnetic susceptibility values. Based on these values a tetrahedral geometry is proposed for all the complexes. The DNA binding studies against calf thymus DNA (CT DNA) revealed an intercalative mode of binding has existed between DNA and metal complex and also metal complexes can cleave the supercoiled pBR 322 DNA effectively. The Schiff bases and metal complexes were also examined for antimicrobial studies against bacterial species of two gram-positive and two gram- negative strains and also two fungal strains and observed that complexes showed better activity than a free ligand. Further, the cytotoxic activity of synthesized compounds has been done using MTT assay and found that complexes acted as good anticancer agents against both MCF7 and HeLa cell lines.