Synthesis, characterization, and biological evaluation of some novel Schiff bases as potential metabolic enzyme inhibitors.

In this study, a series of novel Schiff base derivatives containing a pyrazolone ring (2a-e) were designed, successfully synthesized for the first time, and characterized by elemental analysis and some spectroscopic methods. These compounds were tested for their inhibitory activities on acetylcholinesterase (AChE), butyrylcholinesterase (BChE), and the human carbonic anhydrase isoenzymes I and II (hCA I and II). All synthesized molecules indicated significant inhibition effects with IC50 values ranging from 14.15 to 107.62 nM against these enzymes. Compound 2d showed the most potent inhibitory activity among the tested molecules toward AChE and BChE (IC50  = 15.07 and 14.15 nM) compared to the standard drug neostigmine. We determined that the IC50 values of the tested molecules ranged between 16.86 and 57.96 nM for hCA I and 15.24-46.21 nM for hCA II. As a consequence, we may say that some of the Schiff base derivatives may be used as potential drug candidates in later studies.