Synthesis of Novel Hydrazide–Hydrazone Compounds and <i>In Vitro</i> and <i>In Silico</i> Investigation of Their Biological Activities against AChE, BChE, and hCA I and II

Abstract

The abnormal levels of the human carbonic anhydrase isoenzymes I and II (hCA I and II) and cholinesterase enzymes, namely, acetylcholinesterase (AChE) and butyrylcholinesterase (BChE), are linked with various disorders including Alzheimer's disease. In this study, six new nicotinic hydrazide derivatives (<b>7</b>-<b>12</b>) were designed and synthesized for the first time, and their inhibitory profiles against hCA I, hCA II, AChE, and BChE were investigated by <i>in vitro</i> assays and <i>in silico</i> studies. The structures of novel molecules were elucidated by using spectroscopic techniques and elemental analysis. These molecules showed inhibitory activities against hCA I and II with IC₅₀ values ranging from 7.12 to 45.12 nM. Compared to reference drug acetazolamide (AZA), compound <b>8</b> was the most active inhibitor against hCA I and II. On the other hand, it was determined that IC₅₀ values of the tested molecules ranged between 21.45 and 61.37 nM for AChE and between 18.42 and 54.74 nM for BChE. Among them, compound <b>12</b> was the most potent inhibitor of AChE and BChE, with IC₅₀ values of 21.45 and 18.42 nM, respectively. In order to better understand the mode of action of these new compounds, state-of-the-art molecular modeling techniques were also conducted.