2'-Aryl and 4'-arylidene substituted pyrazolones: As potential α-amylase inhibitors

Acarbose and voglibose are well-known α-amylase inhibitors used for the management of type-II diabetes mellitus. Unfortunately, these well-known and clinically used inhibitors are also associated with several adverse effects. Therefore, there is still need to develop the safer therapy. Despite of a broad spectrum of biological significances of pyrazolone, it is infrequently evaluated for α-amylase inhibition. Current study deals with the synthesis and biological screening of aryl and arylidene substituted pyrazolones 1-18 for their potential α-amylase inhibitory activity. Structures of synthetic derivatives 1-18 were identified by different spectroscopic techniques. All compounds 1-18 (IC₅₀ = 1.61 ± 0.16 μM to 2.38 ± 0.09 μM) exhibited significant to moderate inhibitory potential when compared to standard acarbose (IC₅₀ = 1.46 ± 0.26 μM). A number of derivatives including 8-12 (IC₅₀ = 1.68 ± 0.1 μM to 1.97 ± 0.07 μM) and 14-16 (IC₅₀ = 1.61 ± 0.16 μM to 1.93 ± 0.07 μM) were found to be significantly active. Limited SAR suggested that different substitutions on compounds do not have any significant effect on the inhibitory potential. Compounds were found to be mixed-type inhibitors revealed by kinetic studies. However, in silico study was identified a number of key features participating in the interaction with the binding site of α-amylase enzyme.