Exploring the synthesis, molecular structure and biological activities of novel Bis-Schiff base derivatives: A combined theoretical and experimental approach

Abstract

A library of six novel bis-Schiff base derivatives (2a-f) were synthesized, characterized through modern spectroscopic techniques and screened for their α-glucosidase and α-amylase inhibitory activities (in vitro). In the series, compound 2a (IC50 = 5.64 ± 2.22 µM) and 2f (IC50 = 22.78 ± 2.37 µM) were the most potent α-amylase inhibitors while the remaining four compounds showed significant to less activity. In case of α-glucosidase inhibition, four compounds 2e (IC50 = 2.83 ± 0.18 µM), 2c (IC50 = 7.03 ± 0.15 µM), 2f (IC50 = 9.99 ± 0.20 µM), and 2d (IC50 = 14.68 ± 0.21 µM) displayed excellent inhibitory activity while two compounds showed good inhibitory activity, comparing with the standard acarbose drug. The DFT assay was used to measure the FMO of the synthesized molecules, which indicated their stability, bioactivity and charge transfer. The MEP analysis revealed the distribution of electrostatic potential on the molecular surface of 2a-f, which is helpful for understanding reactivity and interactions. The AIM study showed low hydrogen bond energy and non-covalent interactions. This implies that these molecules may have weak hydrogen bonding and non-covalent interactions, which could affect their chemical behavior. The molecular docking study has provided valuable insights into the interactions between the synthesized derivatives of 2,4-dihydroxyacetophenone with α-glucosidase and α-amylase proteins. The results not only shed light on the binding affinity and key interaction sites but also offer potential avenues for the design of novel drug candidates to control postprandial glucose level in diabetic patients.