Synthesis of Co(II) Metal Complexes of Tryptanthrin Schiff Bases, Characterization, their Biological Evaluation, and Molecular Docking Studies

Tryptanthrin derived Schiff base ligands and their corresponding Co (II) metal complexes[Co(II)(trypNNH۲)۲Cl۲], [Co(trypNNHPh)Cl۲], [Co(II)-(trypNOH)۲] and [Co(trypNNHCSNH۲)۲] were synthesized by directly reacting Tryptanthrin derived ligands (L۱–L۴) with CoCl۲.۶H۲O in methanol/DMF at a ۲:۱ ratio solvent system under reflux condition for ۷۲h. The complexes were characterized and confirmed by Mass, IR, elemental analysis, and Electronic spectral data. The synthesized complexes have been screened for biological evaluation, such as anti-cancer activity against MCF-۷, HeLaby the MTT assay. Cisplatin used as a standard drug. Among the tested complexes, Complex [Co(II)(trypNNH۲)۲Cl۲] with an IC۵۰ value of ۱۱.۰۹ ± ۱.۲۵ µM and ۹.۳۱ ± ۱.۰۷ µM against MCF-۷ and HeLa, respectively, exhibited most effective anti-cancer activity. Molecular docking investigations were done on IDO۱ target by using auto dock. These findings match experimental studies. Among the studied complexes, complex [Co(trypNNH۲)۲Cl۲] with the lowest binding energy of -۱۱.۴۲ kcal/mol, shown its strongest binding with the protein. The complexes were further examined for anti-bacterial activity against two gram+ve bacteria (B. Subtilis and S. Aureus), two Gram -ve bacteria (K. Pneumoniae and E. Coli) and anti-fungal activity against A. Niger and C. Albicans. Most of the synthesized complexes showed good anti-microbial activity. Complex [Co(trypNNHCSNH۲)۲] shown excellent anti-bacterial activity, while the complex [Co (trypNOH)۲]exhibited good anti-fungal activity.

Keywords:

Tryptanthrin , Co (II) complex , cancer activity , bacterial activity , IDO۱ , Molecular docking