Synthesis, structural elucidation, pharmacological and molecular docking studies of terpolymer transition metal complexes

Abstract

A novel monomer (terpolymer) was prepared by mixing of 2-amino-6-nitro-benzimidazole, 2,5-diaminophenol and formaldehyde. Based on the impressive material utilities and therapeutic potential, Cu2+, Ni2+, Co2+ and Zn2+ metal ions were mixed with terpolymer to form different metal chelates. UVVis., IR, 1H NMR, ESR spectral data analysis showed that the prepared metal chelates were of square planar geometry. The molecular mass of polymer was determined using gel permeation chromatography technique. Thermo gravimetric technique was utilized to measure the thermal withstanding ability of terpolymer chelates. The electron transfer mechanism of the metal complexes was investigated by the aid of cyclic voltammetry. The prepared compounds were also screened for antimicrobial efficiency against bacterial strains (B. subtilis, E. coli and S. aureus) and fungal strains (C. albicans, A. niger and A. flavus). The observed results indicated that the chelates showed greater antimicrobial efficiencies than terpolymer ligand. Furthermore, the SOD biomimetic activity of prepared metal chelates was accessed and copper complex was found to possess high antioxidant potential with IC50 value of 0.94 µM. Antituberculosis capacities of terpolymer and its metal chelates was assessed against M. tuberculosis H37Rv strain using MABA assay protocol. Copper complex was found to possess good antitubercular activity with MIC value of 6.20 mg/mL. Molecular docking study was conducted to assess the target for antitubercular activity. It was found that copper complex could be a potent inhibitor of pantothenate synthetase enzyme (a potential target for development of antitubercular drug) of M.tuberculosis with binding energy of -9.8 kcal/mol. Overall copper complex showed good antimicrobial, antioxidant and antitubercular activity when compared to other metal complexes and terpolymer ligand.