ABSTRACT
Isosorbide-2-carbamate-5-esters are highly potent and selective butyrylcholinesterase inhibitors with potential utility in the treatment of Alzheimer's Disease (AD). They are stable in human plasma but in mouse plasma they undergo hydrolysis at the 5-ester group potentially attenuating in vivo potency. In this paper we explore the role of the 5-position in modulating potency. The focus of the study was to increase metabolic stability while preserving potency and selectivity. Dicarbamates and 5-keto derivatives were markedly less potent than the ester class. The 2-benzylcarbamate-5-benzyl ether was found to be potent (IC(50) 52 nM) and stable in the presence of mouse plasma and liver homogenate. The compound produces sustained moderate inhibition of mouse butyrylcholinesterase at 1mg/kg, IP.
Subject(s)
Butyrylcholinesterase/metabolism , Cholinesterase Inhibitors/metabolism , Cholinesterase Inhibitors/pharmacology , Isosorbide/metabolism , Isosorbide/pharmacology , Alzheimer Disease/drug therapy , Animals , Cholinesterase Inhibitors/chemistry , Humans , Isosorbide/chemistry , Mice , Molecular Structure , Plasma/metabolism , Structure-Activity RelationshipABSTRACT
Isosorbide-2-benzyl carbamate-5-benzoate is a highly potent and selective BuChE inhibitor. Meanwhile, isosorbide-2-aspirinate-5-salicylate is a highly effective aspirin prodrug that relies on the salicylate portion to interact productively with human BuChE. By integrating the salicylate group into the carbamate design, we have produced isosorbide-2-benzyl carbamate-5-salicylate, an inhibitor of high potency (150 pM) and selectivity for human BuChE over AChE (666000) and CES2 (23000). Modeling and mutant studies indicate that it achieves its exceptional potency because of an interaction with the polar D70/Y332 cluster in the PAS of BuChE in addition to pseudosubstrate interactions with the active site.
Subject(s)
Anions/metabolism , Butyrylcholinesterase/chemistry , Carbamates/chemistry , Cholinesterase Inhibitors/pharmacology , Isosorbide/analogs & derivatives , Isosorbide/chemistry , Salicylates/pharmacology , Anions/chemistry , Binding Sites , Butyrylcholinesterase/blood , Butyrylcholinesterase/genetics , Carbamates/metabolism , Cholinesterase Inhibitors/chemical synthesis , Cholinesterase Inhibitors/chemistry , Humans , Inhibitory Concentration 50 , Intestines/drug effects , Intestines/enzymology , Isosorbide/chemical synthesis , Isosorbide/metabolism , Isosorbide/pharmacology , Male , Microsomes, Liver/drug effects , Microsomes, Liver/enzymology , Models, Molecular , Molecular Structure , Mutation/genetics , Salicylates/chemical synthesis , Salicylates/chemistry , Structure-Activity RelationshipABSTRACT
In this study, we report the SAR and characterization of two groups of isosorbide-based cholinesterase inhibitors. The first was based directly on the clinically used nitrate isosorbide mononitrate (ISMN) retention of the 5-nitrate group and introduction of a series of 2-carbamate functionalities. The compounds proved to be potent and selective inhibitors of human plasma butyrylcholinesterase ( huBuChE). In the second group, the nitrate ester was removed and replaced with a variety of alkyl and aryl esters. These generally exhibited nanomolar potency with high selectivity for BuChE over acetylcholinesterase (AChE). The most potent and selective compound was isosorbide-2-benzyl carbamate-5-benzoate with an IC 50 of 4.3 nM for BuChE and >50000 fold selectivity over human erythrocyte AChE. Inhibition with these compounds is time-dependent, competitive, and slowly reversible, indicating active site carbamylation.
