Pyrazole phenylcyclohexylcarbamates as inhibitors of human fatty acid amide hydrolases (FAAH)

Synthesis, evaluation and mechanism study of novel pyrazole enamides to alleviate lung injury

Particulate matter with diameter ≤2.5 μm particles (PM2.5) can trigger pulmonary inflammation and lung injury. However, there is still no specific and effective treatment. Lansiumamide B (LB) is a natural cis-enamide compound isolated from wampee seeds, and has potential anti-inflammatory effect. Herein, two series of pyrazole enamide analogues were designed and synthesized based on the scaffold hopping strategy. The inhibition rates of inflammatory cytokines on compound 11a were superior to other compounds and exhibited good dose-dependent manner and safety. Mechanism studies shown that 11a activated the Keap1/Nrf2/HO-1 signaling pathway and promoted Nrf2 entering into nucleus. Further, 11a alleviated pulmonary inflammation, collagen formation and mucus secretion in PM2.5 induced lung injury mice. Besides, 11a administration inhibited M1 macrophage polarization and neutrophil infiltration. Overall, 11a is an effective anti-inflammatory agent which might be a potent candidate to treat lung injury.

Structure optimization of Cmpd-15 as negative allosteric modulators for the β2-adrenergic receptor

19 derivatives of 1-benzyl-3-arylpyrazole-5-carboxamides (H1-H19) and 5 derivatives of 1-benzyl-5-arylpyrazole-3-carboxamides (J1-J5) have been designed and synthesized as potential negative allosteric modulators (NAMs) for the β2-adrenergic receptor (β2AR). The new pyrazole derivatives were screened on the classic G-protein dependent signaling pathway at β2AR. The majority of 1-benzyl-3-aryl-pyrazole-5-carboxamide derivatives show more potent allosteric antagonistic activity against β2AR than Cmpd-15, the first reported β2AR NAM. However, the 1-benzyl-5-arylpyrazole-3-carboxamide derivatives exhibit very poor or even no allosteric antagonistic activity for β2AR. Furthermore, the active pyrazole derivatives have relative better drug-like profiles than Cmpd-15. Taken together, we discovered a series of derivatives of 1-benzyl-3-arylpyrazole-5-carboxamides as a novel scaffold of β2AR NAM.

Identifying FAAH Inhibitors as New Therapeutic Options for the Treatment of Chronic Pain through Drug Repurposing

Chronic pain determines a substantial burden on individuals, employers, healthcare systems, and society. Most of the affected patients report dissatisfaction with currently available treatments. There are only a few and poor therapeutic options-some therapeutic agents are an outgrowth of drugs targeting acute pain, while others have several serious side effects. One of the primary degradative enzymes for endocannabinoids, fatty acid amide hydrolase (FAAH) attracted attention as a significant molecular target for developing new therapies for neuropsychiatric and neurological diseases, including chronic pain. Using chemical graph mining, quantitative structure-activity relationship (QSAR) modeling, and molecular docking techniques we developed a multi-step screening protocol to identify repurposable drugs as FAAH inhibitors. After screening the DrugBank database using our protocol, 273 structures were selected, with five already approved drugs, montelukast, repaglinide, revefenacin, raloxifene, and buclizine emerging as the most promising repurposable agents for treating chronic pain. Molecular docking studies indicated that the selected compounds interact with the enzyme mostly non-covalently (except for revefenacin) through shape complementarity to the large substrate-binding pocket in the active site. A molecular dynamics simulation was employed for montelukast and revealed stable interactions with the enzyme. The biological activity of the selected compounds should be further confirmed by employing in vitro and in vivo studies.

On the Biomedical Properties of Endocannabinoid Degradation and Reuptake Inhibitors: Pre-clinical and Clinical Evidence

The endocannabinoid system (ECS) is composed of endogenous cannabinoids; components involved in their synthesis, transport, and degradation; and an expansive variety of cannabinoid receptors. Hypofunction or deregulation of the ECS is related to pathological conditions. Consequently, endogenous enhancement of endocannabinoid levels and/or regulation of their metabolism represent promising therapeutic approaches. Several major strategies have been suggested for the modulation of the ECS: (1) blocking endocannabinoids degradation, (2) inhibition of endocannabinoid cellular uptake, and (3) pharmacological modulation of cannabinoid receptors as potential therapeutic targets. Here, we focused in this review on degradation/reuptake inhibitors over cannabinoid receptor modulators in order to provide an updated synopsis of contemporary evidence advancing mechanisms of endocannabinoids as pharmacological tools with therapeutic properties for the treatment of several disorders. For this purpose, we revisited the available literature and reported the latest advances regarding the biomedical properties of fatty acid amide hydrolase and monoacylglycerol lipase inhibitors in pre-clinical and clinical studies. We also highlighted anandamide and 2-arachidonoylglycerol reuptake inhibitors with promising results in pre-clinical studies using in vitro and animal models as an outlook for future research in clinical trials.

Advances in the discovery of fatty acid amide hydrolase inhibitors: what does the future hold?

INTRODUCTION

Fatty acid amide hydrolase (FAAH) is a membrane-bound enzyme, that inactivates endogenous signaling lipids of the fatty acid amide family, including the endocannabinoid anandamide (N-arachidonoylethanolamine, AEA). The latter compound has been shown to regulate a number of important pathophysiological conditions in humans, like feeding, obesity, immune response, reproductive events, motor coordination, and neurological disorders. Hence, direct manipulation of the endocannabinoid tone is thought to have therapeutic potential. A new opportunity to develop effective drugs may arise from multi-target directed ligand (MTDL) strategies, which brings the concept that a single compound can recognize different targets involved in the cascade of pathophysiological events.

AREAS COVERED

This review reports the latest advances in the development of new single targeted and dual-targeted FAAH inhibitors over the past 5 years.

EXPERT OPINION

In recent years, several FAAH inhibitors have been synthesized and investigated, yet to date none of them has reached the market as a systemic drug. Due to the diligence of inherent redundancy and robustness in many biological networks and pathways, multitarget inhibitors present a new prospect in the pharmaceutical industry for treatment of complex diseases.

A perspective review on fatty acid amide hydrolase (FAAH) inhibitors as potential therapeutic agents

Fatty acid amide hydrolase (FAAH) is an important enzyme creditworthy of hydrolyzing endocannabinoids and related-amidated signalling lipids, discovery of which has pioneered novel arena of pharmacological canvasses to unwrap its curative potency in various diseased circumstances. It presents contemporary basis for understanding molecules regulating and mediating inflammatory reactions, pain, anxiety, depression, and neurodegeneration. FAAH inhibitors form vital approach for discovery of therapeutic agents that are concerned with local elevation of endocannabinoids under certain stimuli, debarring adverse/unwanted secondary effects from global activation of cannabinoid receptors by exogenous cannabimimetics. During past decades, several molecules with excellent potency developed through tailor-made approaches entered into clinical trials, but none could reach market. Hence, hunt for novel, non-toxic and selective FAAH inhibitors are on horizon. This review summarizes present perception on FAAH in conjunction with its structure, mechanism of catalysis and biological functions. It also foregrounds recent development of molecules belonging to diverse chemical classes as potential FAAH inhibitors bobbing up from in-depth chemical, mechanistic and computational studies published since 2015-November 2019, focusing on their potency. This review will assist readers to obtain rationale on FAAH as potential target for addressing various disease conditions, acquiring significant knowledge on recently established inhibitor scaffolds and their development potentials. New technologies including MD-MM simulations and 3D-QSAR studies allow mechanistic characterization of enzyme. Assessment of in-vitro and in-vivo efficacy of existing FAAH inhibitors will facilitate researchers to design novel ligands utilizing modern drug design methods. The discussions will also impose precaution in decision making process, quashing possibility of late stage failure.

Development of Thiazole-5-carboxylate Derivatives as Selective Inhibitors of Monoacylglycerol Lipase as Target in Cancer

INTRODUCTION

The signalling function of 2-arachidonoylglycerol (2-AG) in endocannabinoid system is delineated by Monoacylglycerol lipase (MAGL). MAGL readdresses the lipid stores in the direction of pro-tumorigenic signalling lipids in cancer cells. Selective as well as potent MAGL inhibitors are limited in number hence their continuous development may lead to a breakthrough invention in the field of MAGL inhibitors. In succession of the above, we have synthesised 2-amino-4- methylthiazole-5-carboxylate derivatives and characterised them by collective use of IR, 1H-NMR, 13C-NMR, Mass spectral data and elemental analysis.

METHODOLOGY

Thirteen compounds (3c-g, 4c, 4e, 4f and 6b-f) inhibited MAGL with IC50 value 0.037- 9.60 µM. Two compounds (3g and 4c) were found to be most potent with IC50 values 0.037 and 0.063µM, respectively. Thirty synthesised compounds were sent to NCI for anticancer screening, out of which nine compounds were selected for one dose anticancer assay. Compounds 3g (NSC:788170) and 4c (NSC:788176)were found to be the most potent during one dose anticancer screening and fulfilled the specified threshold for growth inhibition criteria of NCI and were further selected for full panel five dose assay at 10-fold dilutions of five different concentrations.

CONCLUSION

Compound 3g displayed GI50 value 0.865 μM against EKVX (Non-Small Cell Lung Cancer cell line), and 1.20 µM against MDA-MB-468 (Breast Cancer cell Line), while (4c) showed GI50 value 0.34 and 0.96 µM against HOP-92 and EKVX (Non-Small Cell Lung Cancer cell line) and 1.08 µM against MDA-MB-231/ATCC(Breast Cancer cell Line). In addition, molecular docking studies of the said MAGL inhibitors have also been presented in this article.

The in vivo and in vitro phase I metabolism of FYL-67, a novel oxazolidinone antibacterial drug, studied by LC-MS/MS

In our previous study, FYL-67, a novel linezolid analogue with the morpholinyl ring replaced by a 4-(pyridin-2-yl)-1H-pyrazol-1-yl group, was demonstrated to own an excellent activity against Gram-positive organisms,such as methicillin-resistant Staphylococcus aureus (MRSA). However, metabolic biotransformation was not investigated. This study was performed to identify the phase I metabolites of FYL-67 using liquid chromatography-tandem mass spectrometry (LC-MS/MS). The chemical structures were confirmed by comparison with corresponding chemical standards obtained internal. Primary elucidation of the metabolic pathway of FYL-67 in vitro was performed using liver preparations (microsomes and hepatocytes) from rats and humans, and SD (Sprague Dawley, rat, rattus norvegicus) rats were used for the study of in vivo approach. To the end, two metabolites (M1 and M2 ) were detected after in vitro as well as in vivo experiments. Based on LC-MS/MS analyses, the metabolites were demonstrated to be 5-(aminomethyl)-3-(3-fluoro-4-(4-(pyridin-2-yl)-1H-pyrazol-1-yl)phenyl)oxazolidin-2-one (M1 ) and 3-(3-fluoro-4-(4-(pyridin-2-yl)-1H-pyrazol-1-yl)phenyl)-5-(hydroxymethyl)oxazolidin-2-one (M2 ). Amide hydrolysis at acetyl group of FYL-67 leading to the formation of M1 was observed and suggested to play a major role in both in vivo and in vitro phase I metabolism of FYL-67. M1 was demonstrated to undergo a further oxidation to form M2 . In addition, the results indicated no species difference existing between rats and humans. The outcomes of our research can be utilized for the development and validation of the analytical method for the quantification of FYL-67 as well as its metabolites in biological samples. Furthermore, it is helpful to conduct studies of pharmacodynamics and toxicodynamics. Copyright © 2015 John Wiley & Sons, Ltd.