Soluble epoxide hydrolase (sEH) plays a critical role in inflammation by modulating levels of epoxyeicosatrienoic acids (EETs) and other epoxy fatty acids (EpFAs). Here, we investigate the possible role of sEH in lipopolysaccharide (LPS)-mediated macrophage activation and acute lung injury (ALI). In this study, we found that a small molecule, wedelolactone (WED), targeted sEH and led to macrophage inactivation. Through the molecular interaction with amino acids Phe362 and Gln384, WED suppressed sEH activity to enhance levels of EETs, thus attenuating inflammation and oxidative stress by regulating glycogen synthase kinase 3beta (GSK3beta)-mediated nuclear factor-kappa B (NF-kappaB) and nuclear factor E2-related factor 2 (Nrf2) pathways in vitro. In an LPS-stimulated ALI animal model, pharmacological sEH inhibition by WED or sEH knockout (KO) alleviated pulmonary damage, such as the increase in the alveolar wall thickness and collapse. Additionally, WED or sEH genetic KO both suppressed macrophage activation and attenuated inflammation and oxidative stress in vivo. These findings provided the broader prospects for ALI treatment by targeting sEH to alleviate inflammation and oxidative stress and suggested WED as a natural lead candidate for the development of novel synthetic sEH inhibitors.
In this study, forty-nine kinds of traditional Chinese medicines (TCMs) were evaluated for their inhibitory activities against human carboxylesterase 2 (HCE 2) using a human liver microsome (HLM) system. Swertia bimaculata showed significant inhibition on HCE 2 at 10mug/mL among forty-nine kinds of TCMs. The extract of Swertia bimaculata was separated by preparative HPLC to afford demethylbellidifolin (1) identified by MS, (1)H NMR, and (13)C NMR spectra. Demethylbellidifolin (1) was assayed for its inhibitory HCE 2 effect by HCE 2-mediated DDAB hydrolysis, and its potential IC50 value was 3.12+/-0.64muM. Demethylbellidifolin (1) was assigned as a mixed-type competitive inhibitor with the inhibiton constant Ki value of 6.87microM by Lineweaver-Burk and slope plots. Living cell imaging was conducted to corroborate its inhibitory HCE 2 activity. Molecular docking indicated potential interactions of demethylbellidifolin (1) with HCE 2 through two hydrogen bonds of the C-3 and C-5 hydroxy groups with amino acid residues Glu227 and Ser228 in the catalytic cavity, respectively.
Title: Design, Synthesis and Insecticide Activity of Novel Acetylcholinesterase Inhibitors: Triazolinone and Phthalimide Heterodimers Xie R, Mei X, Ning J Ref: Chem Pharm Bull (Tokyo), 67:345, 2019 : PubMed
Based on the "cluster effect" and the structure characters of acetylcholinesterase (AChE; EC 3.1.1.7), a new series of 1,2,4-triazolin-3-one and phthalimide heterodimers were designed, synthesized, and evaluated as potent dual acetylcholinesterase inhibitors (AChEIs). Most of the synthesized compounds showed good in vitro inhibitory activities towards both Drosophila melanogaster acetylcholinesterase (DmAChE) and Musca domestica acetylcholinesterase (MdAChE). Among them, 5g was found to be the most potent anti-AChE derivate (5g, IC50 = 8.07 microM to DmAChE, IC50 = 32.24 microM to MdAChE). It was 2.31- and 1.35-fold more active than the positive control ethion (CP, IC50 = 18.62 microM to DmAChE, IC50 = 43.56 microM to MdAChE). The docking model study revealed that 5g possessed the fitted spatial structure and bound to the central pocket and peripheral site of DmAChE. Moreover, most compounds demonstrated high insecticidal activity to Lipaphis erysimi and Tetranychus cinnabarinus at the concentration of 300 mg/L.
As a part of our searching for natural human carboxylesterase 2 (human CES 2) inhibitors from traditional Chinese medicine, we found that the extract of Alisma orientale significantly inhibited human CES 2 in vitro. The investigation on A. orientale led to the isolation of a new protostane-type triterpenoid alismanin I (1). Its structure was determined according to HRESIMS, 1D and 2D NMR spectra. Alismanin I (1) displayed significantly inhibitory activity against human CES 2 with IC50 value of 1.31+/-0.09muM assayed by human CES 2-mediated DDAB hydrolysis. According to its inhibition kinetic result, compound 1 was a noncompetitive type inhibitor, and its Ki was 3.65muM. Its inhibitory effect was confirmed in living cell level through a visual manner. The potential interaction mechanism of compound 1 with human CES 2 was also analyzed by circular dichroism (CD) spectrum and molecular docking.
DDAB (6,8-dichloro-9,9-dimethyl-7-oxo-7,9-dihydroacridin-2-yl benzoate) is a newly developed near-infrared fluorescent probe for human carboxylesterase 2 (hCE2), exhibiting high specificity and good reactivity for real-time monitoring the enzymatic activities of hCE2 in complex biological systems. In order to explore the applicability of DDAB in commonly used animal species, the interspecies difference in DDAB hydrolysis was carefully investigated by using liver microsomes from human and five experimental animals including mouse, rat, dog, minipig and monkey. Metabolite profiling demonstrated that DDAB hydrolysis could be catalyzed by all tested liver microsomes from different animals but displayed significant difference in the reaction rate. Chemical inhibition assays demonstrated that carboxylesterases (CEs) were the major enzymes involved in DDAB hydrolysis in all tested liver microsomes, indicating that DDAB was a selective substrate of CEs in a variety of mammals. However, the differential effects of loperamide (LPA, a specific inhibitor against hCE2) on DDAB hydrolysis among various species were observed. The apparent kinetic parameters and the maximum intrinsic clearances (CLmax) for DDAB hydrolysis in liver microsomes from different animals were determined, and the order of CLmax values for the formation of DDAO was CyLM>MLM approximately PLM>RLM>HLM approximately DLM. These findings were helpful for the rational use of DDAB as an imaging tool for CE2 in different mammals, as well as for translational researches on the function of mammalian CEs and CE2-associated drug-drug interactions.
A new protostane-type triterpenoid, 5beta,29-dihydroxy alisol A (1) was isolated from Alisma plantago-aquatica subsp. orientale (Sam.) Sam. as well as 12-deoxyphorbol-13alpha-pentadecanoate (2). We first report the presence of compound 2 in the genus Alisma. Their structures were established on the basis of 1D and 2D NMR, and HRESIMS spectroscopic analyses. All the isolated compounds were assayed for their inhibitory effects against human carboxylesterase 2 (HCE-2). Compounds 1 and 2 displayed inhibitory activities against HCE-2 with IC50 values of 29.2 and 4.6 muM, respectively. The interaction mechanisms of HCE-2 with compounds 1 and 2 were investigated by molecular docking, respectively.
3-Acetyl-11-keto-beta-boswellic acid (AKBA) and 11-keto-beta-boswellic acid (KBA) are widely used in the clinic as anti-inflammatory drugs. However, these drugs have the poor bioavailability, which may be caused by their extensive metabolism. In this study, we systemically characterized both phase I and II metabolism of AKBA and KBA in vitro. In total, four major metabolites were firstly biosynthesized and identified using 1D and 2D NMR spectroscopy. Among them, three metabolites were novel. The kinetic parameters (K m , V max , CL int, and K i ) were also analyzed systematically in various biological samples. Finally, the deacetylation of AKBA and hydroxylation of KBA were confirmed to be the major metabolic pathways based on their large CL int and the high amounts of KBA (46.7%) and hydroxylated KBA (50.8%) along with a low amount of AKBA (2.50%) in human primary hepatocytes. Carboxylesterase 2 (CE2) selectively catalyzed the deacetylation of AKBA to form KBA. Although CYP3A4, CYP3A5, and CYP3A7 catalyzed the metabolism of KBA, CYP3A4 played a predominant role in the hydroxylation reaction of KBA in human. Notably, deacetylation and regioselective hydroxylation exhibited considerable species differences. Deacetylation was only observed in human liver microsomes and primary human hepatocytes; 21- and 20-mono-hydroxylation of KBA were primarily observed in human, monkey, and dog; and 16- and 30-mono-hydroxylation were observed in other species. More importantly, all four mono-hydroxylation metabolites exhibited a moderate anti-inflammatory activity. The 21- and 20-hydroxylation metabolites inhibited the expression of iNOS, the LPS-induced activation of IkBalpha and p65 phosphorylation, and suppressed p65 nuclear translocation in RAW264.7 cells.
Title: Design, synthesis and bioactivity of novel phthalimide derivatives as acetylcholinesterase inhibitors Si W, Zhang T, Zhang L, Mei X, Dong M, Zhang K, Ning J Ref: Bioorganic & Medicinal Chemistry Lett, 26:2380, 2016 : PubMed
A series of novel phthalimide derivatives related to benzylpiperazine were synthesized and evaluated as cholinesterase inhibitors. The results showed that all compounds were able to inhibit acetylcholinesterase (AChE), with two of them dramatically inhibiting butyrylcholinesterase (BuChE). Most compounds exhibited potent anti-AChE activity in the range of nM concentrations. In particular, compounds 7aIII and 10a showed the most potent activity with the IC50 values of 18.44nM and 13.58nM, respectively. To understand the excellent activity of these compounds, the structure-activity relationship was further examined. The protein-ligand docking study demonstrated that the target compounds have special binding modes and these results are in agreement with the kinetic study.
Fructus Psoraleae (FP) is an edible Chinese herbal which is widely used in Asia for the treatment of various diseases including asthma, diarrhea, and osteoporosis. This study aimed to investigate the inhibitory effects of the crude ethanol extract from FP on human carboxylesterase 2 (hCE2), as well as to identity and characterize the naturally occurring inhibitors of hCE2 in FP. Our results demonstrated that the ethanol extract of FP displayed potent inhibitory effects towards hCE2, while five major bioactive constitutes in FP were efficiently identified by LC-DAD-ESI-MS/MS, with the aid of LC-based activity profiling. The identified bioactive compounds including neobavaisoflavone, isobavachalcone, bavachinin, corylifol A and bakuchiol were found to be naturally occurring potent inhibitors of hCE2, with low Ki values ranging from 0.62muM to 3.89muM. This is the first report of the chemical constitutes in FP as potent inhibitors of hCE2.
Title: A highly selective long-wavelength fluorescent probe for the detection of human carboxylesterase 2 and its biomedical applications Feng L, Liu ZM, Xu L, Lv X, Ning J, Hou J, Ge GB, Cui JN, Yang L Ref: Chem Commun (Camb), 50:14519, 2014 : PubMed
A highly selective long-wavelength fluorescent probe TCFB has been developed for the detection of hCE2. The probe can be used for real-time monitoring of hCE2 activity in complex biological systems.
Title: A highly selective fluorescent ESIPT probe for the detection of Human carboxylesterase 2 and its biological applications Feng L, Liu ZM, Hou J, Lv X, Ning J, Ge GB, Cui JN, Yang L Ref: Biosensors & Bioelectronics, 65C:9, 2014 : PubMed
A new ratiometric florescence probe derived from 3-hydroxyflavone (3-HF) has been developed for selective and sensitive detection of human carboxylesterase 2 (CE2). The probe is designed by modulating the excited state intramolecular proton transfer (ESIPT) emission of 3-HF via introducing of 4-ethylbenzoyloxy group. Under physiological conditions, probe 1 displays satisfying stability with very low background signal, but it can be selectively hydrolyzed by CE2 to release free 3-HF which brings remarkable changes in fluorescence spectrum. Both reaction phenotyping and chemical inhibition assays demonstrate that probe 1 is highly selective for CE2 over other human hydrolases including carboxylesterase 1, cholinesterases and paraoxonases. Probe 1 has been applied successfully to measure the real activities of CE2 in human biological samples, as well as to screen CE2 inhibitors by using tissue preparations as the enzymes sources. Additionally, probe 1 is cell membrane permeable and can be used for cellular imaging of endogenous CE2 in living cells. All of these features make it possible to serve as a promising tool for exploring the individual differences in biological function of CE2, as well as for rapid screening of selective and potent inhibitors of CE2 for further clinical use.
Title: A ratiometric fluorescent sensor for highly selective detection of human carboxylesterase 2 and its application in living cells, Liu ZM, Feng L, Hou J, Lv X, Ning J, Ge GB, Wang KW, Cui JN, Yang L Ref: Sensors and Actuators B: Chemical, 205:151, 2014 : PubMed
A new ratiometric fluorescent probe derived from 4-hydroxy-N-butyl-1,8-naphthalimide (HNN) has been developed for selective detection of human carboxylesterase 2 (hCE2). The probe is designed by introducing benzoyl moiety to HNN, based on the intramolecular charge transfer (ICT) mechanism. The probe displays satisfying stability under physiological pH conditions with very low background fluorescence signal, but it can be rapidly hydrolyzed by hCE2 and release of HNN which leads to a remarkable red shift in emission spectra (148nm). The newly designed probe exhibits excellent selectivity towards hCE2 over other human hydrolases, while the interference from various biologically relevant chemicals can be negligible. Its potential biological applications including inhibitor screening using human tissue preparations as enzyme sources, as well as fluorescence imaging of endogenous hCE2 in human living cells, have also been demonstrated.
Title: 2-{(E)-4-[4-(Trifluoro-meth-yl)phen-oxy]but-2-en-yloxy}phenyl N-methyl-carbamate Ma HJ, Xu MH, Zhang JH, Li JH, Ning J Ref: Acta Crystallographica Sect E Struct Rep Online, 69:o326, 2013 : PubMed
In the title compound, CHFNO, which was designed and synthesized as a dual-site inhibitor of insect AChE (acetyl-cholinesterase), the dihedral angle between the methyl-carbamate group and the benzene ring is 72.47 (6) degrees . In the crystal, inversion dimers are linked by pairs of N-Hcdots, three dots, centeredO hydrogen bonds.
Title: Design, synthesis and biological evaluation of organophosphorous-homodimers as dual binding site acetylcholinesterase inhibitors Xie R, Zhao Q, Zhang T, Fang J, Mei X, Ning J, Tang Y Ref: Bioorganic & Medicinal Chemistry, 21:278, 2013 : PubMed
The cluster effect is an effective strategy to explore new lead compounds, and has been successfully applied in rational drug design and screening. A series of novel organophosphorous-homodimers were designed and synthesized based on the dual-site structure characteristics of acetylcholinesterase (AChE). The compounds were evaluated in vitro for their inhibitory activity to AChE extracted from Drosophila melanogaster and Musca domestic. Compound 4H showed an excellent inhibitor activity to both Drosophila melanogaster and Musca domestic with the corresponding IC(50) values of 23 and 168nM, respectively. Meanwhile, its activities against Drosophila melanogaster and Musca domestic AChE were more than 10,00,000 and 100,000-fold higher compared with the parent compound (MH), and was up to 245 and 107-fold higher than those of the positive control omethoate. The molecular docking study revealed that 4H possessed an optimal spacer length and can perfectly fit into the central pocket, active gorge, and peripheral site of DmAChE, and consequently exhibited highly improved inhibitor potency to DmAChE. The bioassay tests showed that 4 series compounds showed prominent insecticidal activities against both Lipaphser erysimi and Tetranychus cinnbarinus at a concentration of 200mg/L. The insecticide activity of compound 4H was particularly significant that can cause 96% mortality to Tetranychus cinnbarinus after 24h of treatment.
Title: Homo- and hetero-dimers of inactive organophosphorous group binding at dual sites of AChE Zhao Q, Xie R, Zhang T, Fang J, Mei X, Ning J, Tang Y Ref: Bioorganic & Medicinal Chemistry Lett, 21:6404, 2011 : PubMed
Homo- and hetero-dimers of inactive organophosphorous group(s) dramatically enhanced the acetylcholinesterase (AChE; EC 3.1.1.7) inhibiting potency, with the highest potency observed at a tether length of 6 methylene groups (6d) for the homodimers, and 7 methylene groups (8e) for the heterodimers. The docking model of Drosophila melanogaster AChE suggested that 6d and 8e bound at the catalytic and peripheral sites of AChE, in which two organophosphorous groups of 6d individually oriented towards TRP83 of catalytic sites and TRP321 of peripheral sites, and phthalicimide group of 8e was appropriately arranged for a pi-pi interaction with the phenyl ring of TYR330, furthermore, the organophosphorous group introduced hydrophobic interaction with TRP83. The compounds prepared in this work demonstrated high insecticidal activity to Lipaphis erysimi and Tetranychus cinnbarinus at the concentration 300mg/L.
Title: Synthesis and insecticidal activity of novel carbamate derivatives as potential dual-binding site acetylcholinesterase inhibitors Ma HJ, Xie RL, Zhao QF, Mei XD, Ning J Ref: Journal of Agricultural and Food Chemistry, 58:12817, 2010 : PubMed
In biological systems, bivalent ligands often possess increased functional affinity for their receptors compared with monovalent ligands. On the basis of the structure of acetylcholinesterase (AChE), a series of novel carbamate heterodimetic derivatives were designed and synthesized with the aim of increasing the potency toward AChE inhibition. The AChE inhibitory ability of all the novel compounds was tested using AChE obtained from the brain of the housefly. The bioassay results showed that compounds 6j, 6k, 6m, 6n, 6p, and 6q had increased inhibitory activities in comparison with parent phenyl N-methylcarbamate (MH) at the concentration of 100 mg/L. Among them, the most potent AChE inhibitor of these compounds was 6q (IC(50) = 12 muM), which showed 62-fold greater AChE inhibitory activity than that of MH and 12-fold greater activity than metolcarb (MT), which suggested that the 3-nitrophenoxy moiety of compound 6q was able to interact with the aromatic amino acid residues lining the gorge and the phenyl N-methylcarbamate moiety was able to interact with the catalytic sites of AChE, simultaneously. The insecticidal activities of compounds 6j, 6k, 6m, 6n, 6p, and 6q were further evaluated. Consistent with the result in vitro bioassay, those compounds demonstrated better activities against Lipaphis erysimi than parent compound MH at the concentration of 300 mg/L, and compound 6q showed the best insecticidal activity, causing 98% mortality after 24 h of treatment.
Title: Novel acetylcholinesterase inhibitors: Synthesis and structure-activity relationships of phthalimide alkyloxyphenyl N,N-dimethylcarbamate derivatives Zhao Q, Yang G, Mei X, Yuan H, Ning J Ref: Pesticide Biochemistry and Physiology, 95:131, 2009 : PubMed
Based on the multiple binding sites of acetylcholinesterase (AChE), a series of AChE inhibitors: phthalimide alkyloxyphenyl N,N-dimethylcarbamate were designed and synthesized. AChE inhibitory activity and structure-activity relationship of the compounds were researched also. The influence of structural variations on the inhibitory potency was carefully investigated by modifying different alkyloxy chain length and position between phthalimide and phenyl N,N-dimethylcarbamate (PDM). The biological properties of the series were investigated by considering the activity on isolated enzyme. Some of the newly synthesized derivatives, when tested on isolated AChE from head of housefly (Musca domestica), were more active than PDM. The compounds J1, J2 and K1-K8 demonstrated higher inhibitory activity (5- to 404-fold) for AChE than that of PDM. In particular, compound K1 displayed the best AChE inhibition (404-fold higher than PDM), which suggested that phthalimide group of K1 strongly bound at the residues lining the gorge while phenyl N,N-dimethylcarbamate bound at the catalytic site.
Title: Design of novel carbamate acetylcholinesterase inhibitors based on the multiple binding sites of acetylcholinesterase Zhao Q, Yang G, Mei X, Yuan H, Ning J Ref: Journal of Pesticide Science, 33:371, 2008 : PubMed
This work describes the design, synthesis, AChE inhibitory activity, and structure-activity relationship of compounds related to a recently discovered series of AChE inhibitors: phthalimide alkyloxyphenyl N-methylcarbamates. The influence of structural variations on inhibitory potency was carefully investigated by modifying different alkyloxy chain lengths and positions between phthalimide and phenyl N-methylcarbamate. The biological properties of the series were investigated in some detail by considering their activity on isolated enzymes. All of the newly synthesized derivatives, when tested on isolated AChE from the brain of the housefly (Musca domestica), were more active than phenyl N-methylcarbamate. In particular, compound I1 displayed the best AChE inhibition (352-fold higher than phenyl N-methylcarbamate, and 29-fold higher than metolcarb), which suggested that the phthalimide group of I1 bound strongly to the residues lining the gorge, and phenyl N-methylcarbamate bound at the catalytic sites.
