Structural aspects of 4-aminoquinolines as reversible inhibitors of human acetylcholinesterase and butyrylcholinesterase

Abstract

Eight derivatives of 4-aminoquinolines differing in the substituents attached to the C(4)-amino group and C(7)were synthesised and tested as inhibitors of human acetylcholinesterase (AChE)and butyrylcholinesterase (BChE). Both enzymes were inhibited by all of the compounds with inhibition constants (K i )ranging from 0.50 to 50 μM exhibiting slight selectivity toward AChE over BChE. The most potent inhibitors of AChE were compounds with an n-octylamino chain or adamantyl group. The shortening of the chain length resulted in a decrease in AChE inhibition by 5–20 times. Docking studies revealed that the quinoline group within the AChE active site was positioned in the choline binding site, while the C(4)-amino group substituents, depending on their lipophilicity, could establish hydrogen bonds or π-interactions with residues of the peripheral anionic site. The most potent inhibitors of BChE were compounds with the most voluminous substituent on C(4)-amino group (adamantyl)or those with a stronger electron withdrawing substituent on C(7)(trifluormethyl group). Based on AChE inhibition, compounds with an n-octylamino chain or adamantyl substituent were shown to possess the capacity for further development as potential drugs for treatment of neurodegenerative diseases. © 2019 Elsevier B.V.