Synthesis, characterization, biological activity and molecular docking studies of novel schiff bases derived from thiosemicarbazide: Biochemical and computational approach

In this study, eight new Schiff base derivatives (2a-h) were synthesized and their inhibition activities against Acetylcholinesterase (AChE), Butyrylcholinesterase (BChE), alpha-Glucosidase and Lactoperoxidase (LPO) were investigated. Structures of the synthesized compounds were characterized using H-1 and C-13 nuclear magnetic resonance (NMR), infrared spectroscopy (IR), and high-resolution mass spectrometry (HRMS) spectroscopic methods. AChE was inhibited by these novel Schiff bases (2a-h) in low nanomolar levels, the K-i of which differed between 592.66 +/- 57.04 and 810.78 +/- 84.06 nM. Against BChE, the novel compounds demonstrated Kis varying from 358.31 +/- 37.88 to 577.24 +/- 59.91 nM. Also, these novel Schiff bases effectively inhibited alpha-glucosidase, with K-i values in the range of 1.56 +/- 0.32 to 14.78 +/- 2.57 nM. For LPO, K-i values were in the range of 3.96 +/- 0.37 to 12.75 +/- 0.06 nM. For alpha-glucosidase, the most effective molecules were 2b and 2 g with K-i values of 1.56 +/- 0.32 and 14.78 +/- 2.57 nM, respectively. Molecular docking results showed that the compounds have binding affinity with -5.559,-9.698, -7.606, and -6.971 kcal/mol against LPO, AChE, BChE, and alpha-glucosidase enzyme, respectively. It has been observed that the furan and thiosemicarbazone moieties play an important role in the inhibition of these enzymes. (C) 2020 Elsevier B.V. All rights reserved.

Automated summary

In this study, eight new Schiff base derivatives were synthesized and found to exhibit inhibitory activities against various enzymes in low nanomolar levels. Molecular docking results indicated that the furan and thiosemicarbazone moieties play essential roles in enzyme inhibition.