ABSTRACT
Here we investigate the suitability of in vitro models to assess the skin and eye irritation potential of six microbial strains. Acute skin irritation was tested according to the unmodified and modified OECD test guideline (OECD TG) 439, while acute eye irritation was examined using the OECD TG 491 and 492. The OECD TG 439 guideline, modified to introduce 8-10 µg/mL of streptomycin during the recovery phase and use of test items containing 100% microbial product instead of finished formulae, was found to be suitable for skin irritation evaluation. On the other hand, the OECD TG 491 procedure was the most appropriate for evaluating eye irritation. None of the six microbial strains, namely, Lactiplantibacillus plantarum (IMI 507026, IMI 507027, IMI 507028), Lacticaseibacillus rhamnosus (IMI 507023), and Pediococcus pentosaceus (IMI 507024, IMI 507025), tested in this study caused skin or eye irritation under the study condition.
Subject(s)
Lactobacillales , Skin Diseases , Animals , Irritants/toxicity , Animal Testing Alternatives , Skin , Skin Irritancy TestsABSTRACT
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.
Subject(s)
Butyrylcholinesterase/metabolism , Carbamates/chemistry , Cholinesterase Inhibitors/chemical synthesis , Cholinesterase Inhibitors/pharmacology , Esters/chemical synthesis , Esters/pharmacology , Isosorbide/chemistry , Binding Sites , Cholinesterase Inhibitors/chemistry , Esters/chemistry , Humans , Models, Molecular , Molecular Structure , Structure-Activity RelationshipABSTRACT
Reported here is the synthesis and SAR of novel group of highly potent and selective inhibitors of human plasma butyrylcholinesterase (BuChE; EC 3.1.1.8). The design is based on the discovery that isosorbide 2-esters are hydrolysed by BuChE at exceptionally rapid rates. Two families of carbamates were synthesised in which the vulnerable 2-ester was replaced with a carbamate or reversed carabamate. Several compounds in one of the families are among the most potent and selective BuChE inhibitors reported.
