Structure-activity relationships of amide-phosphonate derivatives as inhibitors of the human soluble epoxide hydrolase

Relationship between Structure and Antibacterial Activity of α-Aminophosphonate Derivatives Obtained via Lipase-Catalyzed Kabachnik-Fields Reaction

We reported a new method dealing with the synthesis of novel pharmacologically relevant α-aminophosphonate derivatives via a lipase-catalyzed Kabachnik−Fields reaction with yields of up to 93%. The advantages of this protocol are excellent yields, mild reaction conditions, low costs, and sustainability. The developed protocol is applicable to a range of H-phosphites and organic amines, providing a wide substrate scope. A new class of α-aminophosphonate analogues possessing P-chiral centers was also synthesized. The synthesized compounds were characterized on the basis of their antimicrobial activities against E. coli. The impact of the various alkoxy groups on antimicrobial activity was demonstrated. The crucial role of the substituents, located at the aromatic rings in the phenylethyloxy and benzyloxy groups, on the inhibitory action against selected pathogenic E. coli strains was revealed. The observed results are especially important because of increasing resistance of bacteria to various drugs and antibiotics.

Discovery of Soluble Epoxide Hydrolase Inhibitors from Chemical Synthesis and Natural Products

Soluble epoxide hydrolase (sEH) is an α/β hydrolase fold protein and widely distributed in numerous organs including the liver, kidney, and brain. The inhibition of sEH can effectively maintain endogenous epoxyeicosatrienoic acids (EETs) levels and reduce dihydroxyeicosatrienoic acids (DHETs) levels, resulting in therapeutic potentials for cardiovascular, central nervous system, and metabolic diseases. Therefore, since the beginning of this century, the development of sEH inhibitors is a hot research topic. A variety of potent sEH inhibitors have been developed by chemical synthesis or isolated from natural sources. In this review, we mainly summarized the interconnected aspects of sEH with cardiovascular, central nervous system, and metabolic diseases and then focus on representative inhibitors, which would provide some useful guidance for the future development of potential sEH inhibitors.

Bioisosteric substitution of adamantane with bicyclic lipophilic groups improves water solubility of human soluble epoxide hydrolase inhibitors

A series of inhibitors of the soluble epoxide hydrolase (sEH) containing lipophilic groups of natural origin (camphanyl, norcamphanyl, furan-2-yl) were developed. Inhibitory potency ranging from 0.4 nM to 2.16 μM were obtained. While having the same level of inhibitory activity bicyclic ureas are up to 10-fold more soluble than the corresponding ureas containing adamantyl or 4-trifluoromethoxyphenyl substituents. This makes them easier to formulate, more bioavailable and thus more promising as therapeutic sEH inhibitors. Endo/exo-form of compound 2b derived from l-camphor is 14-fold more potent than the corresponding analogue derived from d-camphor (IC₅₀ = 3.7 nM vs. 50.6 nM) indicating enantiomeric preference.

Computer-Aided Fragment Growing Strategies to Design Dual Inhibitors of Soluble Epoxide Hydrolase and LTA4 Hydrolase

Multitarget ligands are interesting candidates for drug discovery and development due to improved safety and efficacy. However, rational design and optimization of multitarget ligands is tedious because affinity optimization for two or more targets has to be performed simultaneously. In this study, we demonstrate that, given a molecular fragment, which binds to two targets of interest, computer-aided fragment growing can be applied to optimize compound potency, relying on either ligand- or structure-derived information. This methodology is applied to the design of dual inhibitors of soluble epoxide hydrolase and leukotriene A4 hydrolase.

Exploring the size of the lipophilic unit of the soluble epoxide hydrolase inhibitors

Soluble epoxide hydrolase (sEH) inhibitors are potential drugs for several diseases. Adamantyl ureas are excellent sEH inhibitors but have limited metabolic stability. Herein, we report the effect of replacing the adamantane group by alternative polycyclic hydrocarbons on sEH inhibition, solubility, permeability and metabolic stability. Compounds bearing smaller or larger polycyclic hydrocarbons than adamantane yielded all good inhibition potency of the human sEH (0.4 ≤ IC₅₀ ≤ 21.7 nM), indicating that sEH is able to accommodate inhibitors of very different size. Human liver microsomal stability of diamantane containing inhibitors is lower than that of their corresponding adamantane counterparts.

In Vitro and In Silico Insights into sEH Inhibitors with Amide-Scaffold from the Leaves of Capsicum chinense Jacq

Two compounds termed 1 and 2 were isolated from the leaves of Capsicum chinense using column chromatography. Their structures were identified as amide scaffolds by analyzing spectroscopic signals. Compounds 1 and 2 have been confirmed to be competitive soluble epoxide hydrolase (sEH) inhibitors that suppress the catalytic reaction of sEH in a dose-dependent manner in vitro. Molecular docking was used for analyzing two binding clusters of ligand and receptor. The results confirmed that the key amino acids interacting with the ligand were Asp335, Tyr383, and Gln384. On the basis of molecular dynamics, inhibitors 1 and 2 were noted to interact at a distance of 3.5 Å from Asp335, Tyr383, Leu408 and Tyr466, and Asp335, Tyr383, and Tyr466, respectively. These results highlight the potential of N-trans-coumaroyltyramine (1) and N-trans-feruloyltyramine (2) as sEH inhibitors.

Synthesis of α-aminophosphonates using solvate ionic liquids

A range of α-aminophosphonates were accessed in high yields and very rapidly, using solvate ionic liquids as the reaction media.

Relationships of human α/β hydrolase fold proteins and other organophosphate-interacting proteins

Organophosphates (OPs) are either found in nature or synthetized for use as pesticides, flame retardants, neurotoxic warfare agents or drugs (cholinergic enhancers in Alzheimer's disease and myasthenia gravis, or inhibitors of lipases in metabolic diseases). Because of the central role of acetylcholinesterase cholinergic neurotransmission in humans, one of the main purposes for using OPs is inactivation of the enzyme by phosphorylation of the nucleophilic serine residue in the active center. However, hundreds of serine hydrolases are expressed in the human proteome, and many of them are potential targets for OP adduction. In this review, we first situate the α/β hydrolase fold proteins among the distinctively folded proteins known to interact with OPs, in particular the different lipases, peptidases, and enzymes hydrolyzing OPs. Second, we compile the human α/β hydrolases and review those that have been experimentally shown to interact with OPs. Among the 120 human α/β hydrolase fold proteins, 102 have a serine in the consensus GXSXG pentapeptide compatible with an active site, 6 have an aspartate or a cysteine as the active site nucleophile residue, and 12 evidently lack an active site. 76 of the 120 have been experimentally shown to bind an OP.