Synthesis and biological evaluation of copper and cobalt complexes of (5-substituted-salicylidene) isonicotinichydrazide derivatives as antitubercular agents

Cobalt(II) and copper(II) complexes of a series (E)-N'-(5-X-salicylidene)isonicotinohydrazide Schiff bases derived from isonicotinic acid hydrazide and 5-substituted-salicylaldehydes have been synthesized and characterized by FTIR, AAS, UV-Visible spectroscopy and elemental analysis. Evaluation of the in-vitro antitubercular, antioxidant and cytotoxic activities of the compounds was carried out to establish their potential as antituberculosis agents. The FTIR spectra showed that the ligands behave as tridentate dibasic ligands towards the metal ions. The antioxidant activities of the compounds investigated through their scavenging effect on DPPH revealed that the IC50 for the nitro substituted Schiff base was highest, similarly, the LC50 value was much lower than the values for other compounds. The ligand complexes containing the nitro NO2 ( )substituent exhibited enhanced in vitro Mycobacterium tuberculosis and antioxidant activities compared with the ligands and reference compounds (Isoniazid and vitamin C). (C) 2020 The Authors. Published by Elsevier B.V. on behalf of African Institute of Mathematical Sciences / Next Einstein Initiative.