Synthesis of two novel mercaptobenzimidazole derivative Schiff bases and their in vitro antioxidant and enzyme inhibitory effects

In this study, 5-(2-hydroxy-4-methoxybenzylidenamino)-2-mercaptobenzimidazole and 5-(4-hydroxy-3-methoxybenzylidenamino)-2-mercaptobenzimidazole Schiff base compounds were synthesized and their structure were characterized with spectroscopic techniques, namely, 1H NMR, IR, and 13C NMR. In vitro ABTS, DPPH, CUPRAC, and FRAP tests were applied to calculate the antioxidant activities of the newly designed compounds. Beside, the enzyme inhibitory abilities of the mercaptobenzimidazole derivative Schiff base were assessed against the glutathione S-transferase (GST) enzyme. The K-i values were calculated as 20.06 +/- 3.11 and 36.86 +/- 6.17 mu M, as well as the IC50 values were calculated as 6.30 mu M and 5.33 mu M respectively. Besides, molecular docking interactions of the compounds with the GST target enzyme (PDB ID:5JCU) were estimated via Chimera and AutoDock Vina software. -8.7 kcal/mol, and -8.5 kcal/mol were calculated as best binding scores of compounds against the GST enzyme. Since the novel Schiff base, 5-(4-hydroxy-3-methoxybenzylidenamino)-2-mercaptobenzimidazole has a good potential in the GST inhibition, it should be subjected to the further pharmacological studies.