Synthesis and Therapeutic Potential of selected Schiff Bases: In vitro Antibacterial, Antioxidant, Antidiabetic, and Computational Studies

Abstract

In this study, three Schiff base compounds, (E)‐N‐(4‐bromophenyl)‐1‐(2‐nitrophenyl)methanimine (L1), (E)‐2‐((mesitylimino)methyl)phenol (L2), and (E)‐N‐(4‐bromophenyl)‐1‐(pyridin‐2‐yl)methanimine (L3), were synthesized and characterized by various spectroscopic techniques. The antibacterial activity of the compounds was evaluated against Gram‐positive and Gram‐negative bacteria, with L3 demonstrating the most significant activity. The compounds were also evaluated for their antioxidant activity using DPPH, FRAP, and NO scavenging assays. While the compounds exhibited concentration‐dependent scavenging of free radicals, their activity was not as significant as that of the reference, Trolox. Furthermore, L1–L3 were tested for their α‐amylase and α‐glucosidase inhibitory activity, with L1 showing the highest inhibitory activity among the three compounds. The DFT study showed that L1 is the most chemically reactive among the three compounds, having the lowest energy band gap value of 3.82 eV in acetonitrile, the experimental solvent. Molecular docking predicted that L1 and L2 have very strong inhibition equivalents to the standard drugs against bacteria and diabetes. All the compounds showed stronger inhibition against α‐glucosidase than acarbose, while only L1 and L2 exhibited stronger inhibition against α‐amylase than acarbose. It can be deduced that the theoretical studies corroborate well with the experimental, and compounds with the electron‐withdrawing group displayed better medicinal properties than their electron‐donating counterparts.