Synthesis and biological evaluation of indole derivatives as α-amylase inhibitor

A series of twenty indole hydrazone analogs (1-21) were synthesized, characterized by different spectroscopic techniques such as H-1 NMR and EI-MS, and screened for alpha-amylase inhibitory activity. All analogs showed a variable degree of alpha-amylase inhibition with IC50 values ranging between 1.66 and 2.65 mu M. Nine compounds that are 1 (2.23 +/- 0.01 mu M), 8 (2.44 +/- 0.12 mu M), 10 (1.92 +/- 0.12 mu M), 12 (2.49 +/- 0.17 mu M), 13 (1.66 +/- 0.09 mu M), 17 (2.25 +/- 0.1 mu M), 18 (1.87 +/- 0.25 mu M), 20 (1.83 +/- 0.63 mu M), and 19 (1.97 +/- 0.02 mu M) showed potent alpha-amylase inhibition when compared with the standard acarbose (1.05 +/- 0.29 mu M). Other analogs showed good to moderate alpha-amylase inhibition. The structure activity relationship is mainly focusing on difference of substituents on phenyl part. Molecular docking studies were carried out to understand the binding interaction of the most active compounds. (C) 2017 Elsevier Inc. All rights reserved.