Alzheimer's disease (AD) is a complex disorder with unknown etiology. Currently, only symptomatic therapy of AD is available, comprising cholinesterase inhibitors and N-methyl-d-aspartate (NMDA) receptor antagonists. Drugs targeting only one pathological condition have generated only limited efficacy. Thus, combining two or more therapeutic interventions into one molecule is believed to provide higher benefit for the treatment of AD. In the presented study, we designed, synthesized, and biologically evaluated 15 novel fluoren-9-amine derivatives. The in silico prediction suggested both the oral availability and permeation through the blood-brain barrier (BBB). An initial assessment of the biological profile included determination of the cholinesterase inhibition and NMDA receptor antagonism at the GluN1/GluN2A and GluN1/GluN2B subunits, along with a low cytotoxicity profile in the CHO-K1 cell line. Interestingly, compounds revealed a selective butyrylcholinesterase (BChE) inhibition pattern with antagonistic activity on the NMDARs. Their interaction with butyrylcholinesterase was elucidated by studying enzyme kinetics for compound 3c in tandem with the in silico docking simulation. The docking study showed the interaction of the tricyclic core of new derivatives with Trp82 within the anionic site of the enzyme in a similar way as the template drug tacrine. From the kinetic analysis, it is apparent that 3c is a competitive inhibitor of BChE.

• Keywords
• Alzheimer’s disease, N-methyl-d-aspartate receptor, acetylcholinesterase, butyrylcholinesterase, fluorene, in silico, in vitro, multi-target directed ligands,
• MeSH
• Alzheimer Disease drug therapy   enzymology   genetics   pathology   MeSH
• Butyrylcholinesterase chemistry   drug effects   genetics   MeSH
• CHO Cells MeSH
• Cholinesterase Inhibitors chemistry   pharmacology   MeSH
• Cricetulus MeSH
• Fluorenes chemistry   pharmacology   MeSH
• Blood-Brain Barrier drug effects   MeSH
• Enzyme Inhibitors pharmacology   MeSH
• Humans MeSH
• Computer Simulation MeSH
• Receptors, N-Methyl-D-Aspartate antagonists & inhibitors   genetics   MeSH
• Animals MeSH
• Check Tag
• Humans MeSH
• Animals MeSH
• Publication type
• Journal Article MeSH
• Research Support, Non-U.S. Gov't MeSH
• Names of Substances
• Butyrylcholinesterase MeSH
• Cholinesterase Inhibitors MeSH
• fluorene MeSH Browser
• Fluorenes MeSH
• Enzyme Inhibitors MeSH
• N-methyl D-aspartate receptor subtype 2A MeSH Browser
• NR2B NMDA receptor MeSH Browser
• Receptors, N-Methyl-D-Aspartate MeSH