Pyrazolone compounds could inhibit CES1 and ameliorates fat accumulation during adipocyte differentiation.

Carboxylesterase 1 (CES1), a member of the serine hydrolase superfamily, is involved in a wide range of xenobiotic and endogenous substances metabolic reactions in mammals. The inhibition of CES1 could not only alter the metabolism and disposition of related drugs, but also be benefit for treatment of metabolic disorders, such as obesity and fatty liver disease. In the present study, we aim to develop potential inhibitors of CES1 and reveal the preferred inhibitor structure from a series of synthetic pyrazolones (compounds 1-27). By in vitro high-throughput screening method, we found compounds 25 and 27 had non-competitive inhibition on CES1-mediated N-alkylated d-luciferin methyl ester (NLMe) hydrolysis, while compound 26 competitively inhibited CES1-mediated NLMe hydrolysis. Additionally, Compounds 25, 26 and 27 can inhibit CES1-mediated fluorescent probe hydrolysis in live HepG2 cells with effect. Besides, compounds 25, 26 and 27 could effectively inhibit the accumulation of lipid droplets in mouse adipocytes cells. These data not only provided study basis for the design of newly CES1 inhibitors. The present study not only provided the basis for the development of lead compounds for novel CES1 inhibitors with better performance, but also offered a new direction for the explore of candidate compounds for the treatment of hyperlipidemia and related diseases.

Oxazinethione Derivatives as a Precursor to Pyrazolone and Pyrimidine Derivatives: Synthesis, Biological Activities, Molecular Modeling, ADME, and Molecular Dynamics Studies.

In this study, we used oxazinethione as a perfect precursor to synthesize new pyrimidine and pyrazole derivatives with potent biological activities. Biological activities were determined for all compounds against A. flavus, E. coli, S. aureus, and F. moniliform. Compounds 3, 4a-b, and 5 exhibited higher activities toward A. flavus, E. coli, S. aureus, and F. moniliform; this was indicated through the MIC (minimum inhibitory concentration). At the same time, anticancer activities were determined through four cell lines, Ovcar-3, Hela, MCF-7, and LCC-MMk. The results obtained indicated that compound 5 was the most potent compound for both cell lines. Molecular docking was studied by the MOE (molecular operating environment). The in silico ADME of compounds 2 and 5 showed good pharmacokinetic properties. The present research strengthens the applicability of these compounds as encouraging anticancer and antibacterial drugs. Moreover, JAGUAR module MD simulations were carried out at about 100 ns. In addition, spectroscopic studies were carried out to establish the reactions of the synthesized structure derivatives.

Discovery of pyrazolones as novel carboxylesterase 2 inhibitors that potently inhibit the adipogenesis in cells.

Carboxylesterase 2 (CES2) is one of the most important Phase I drug metabolizing enzymes in the carboxylesterase family. It plays crucial roles in the bioavailability of oral ester prodrugs and the therapeutic effect of some anticancer drugs such as irinotecan (CPT11) and capecitabine. In addition to the well-known roles of CES2 in xenobiotic metabolism, the enzyme also participates in endogenous metabolism and the production of lipids. In this study, we synthesized a series of pyrazolones and assayed their inhibitory effects against CES2 in vitro. Structure-activity relationship analysis of these pyrazolones reveals that the introduction of 4-methylphenyl unit (R1), 4-methylbenzyl (R2) and cyclohexyl (R3) moieties are beneficial for CES2 inhibition. Guided by these SARs results, 1-cyclohexyl-4-(4-methylbenzyl)-3-p-tolyl-1H- pyrazol-5(4H)-one (27) was designed and synthesized. Further investigations demonstrated that the compound 27 exhibited stronger CES2 inhibition activity with a lower IC50 value (0.13 µM). The inhibition kinetic study demonstrated that compound 27 inhibited the hydrolysis of CES2-fluorescein diacetate (FD) through non-competitive inhibition. In addition, the molecular docking showed that the core of pyrazolone, the cyclohexane moiety, 4-methylbenzyl and 4-methylphenyl groups in compound 27 all played important roles with the amino acid residues of CSE2. Also, compound 27 could inhibit adipocyte adipogenesis induced by mouse preadipocytes. In brief, we designed and synthesized a novel pyrazolone compound with a strong inhibitory ability on CES2 and could inhibit the adipogenesis induced by mouse preadipocytes, which can be served as a promising lead compound for the development of more potent pyrazolone-type CES2 inhibitors, and also used as a potential tool for exploring the biological functions of CES2 in human being.

Structure-based modification of pyrazolone derivatives to inhibit mTORC1 by targeting the leucyl-tRNA synthetase-RagD interaction.

The enzyme leucyl-tRNA synthetase (LRS) and the amino acid leucine regulate the mechanistic target of rapamycin (mTOR) signaling pathway. Leucine-dependent mTORC1 activation depends on GTPase activating protein events mediated by LRS. In a prior study, compound BC-LI-0186 was discovered and shown to interfere with the mTORC1 signaling pathway by inhibiting the LRS-RagD interaction. However, BC-LI-0186 exhibited poor solubility and was metabolized by human liver microsomes. In this study, in silico physicochemical properties and metabolite analysis of BC-LI-0186 are used to investigate the addition of functional groups to improve solubility and microsomal stability. In vitro experiments demonstrated that 7b and 8a had improved chemical properties while still maintaining inhibitory activity against mTORC1. The results suggest a new strategy for the discovery of novel drug candidates and the treatment of diverse mTORC1-related diseases.

Design, Synthesis, and Structure-Activity Relationship Study of Pyrazolones as Potent Inhibitors of Pancreatic Lipase.

Pancreatic lipase (PL), a key target for the prevention and treatment of obesity, plays crucial roles in the hydrolysis and absorption of in dietary fat. In this study, a series of pyrazolones was synthesized, and their inhibitory effects against PL were assayed by using 4-methylumbelliferyl oleate (4-MUO) as optical substrate for PL. Comprehensive structure-activity relationship analysis of these pyrazolones led us to design and synthesize a novel compound P32 (5-(naphthalen-2-yl)-2-phenyl-4-(thiophen-2-ylmethyl)-2,4-dihydro-3H-pyrazol-3-one) as a potent mixed-competitive inhibitor of PL (IC50 =0.30 µM). In addition, P32 displayed some selectivity over other known serine hydrolases. A molecular docking study for P32 demonstrated that the inhibitory activity of P32 towards PL could be attributed to the π-π interactions of 2-naphthyl unit (R1 ) and hydrophobic interactions of phenyl moiety (R3 ) with the active site of PL. Thus, P32 could serve as promising lead compound for the development of more efficacious and selective pyrazolones-type PL inhibitors for biomedical applications.

A Therapeutic Journey of 5-Pyrazolones as a Versatile Scaffold: A Review.

A sizeable proportion of currently marketed drugs come from heterocycles. The heterocyclic moiety 5-pyrazolone is well known five-membered ring containing nitrogen. Derivatives of this wonder nucleus have exhibited activities as diverse as antimicrobial, anti-inflammatory, analgesic, antidepressant, anticonvulsant, antidiabetic, antihyperlipidemic, antiviral, antitubercular, antioxidant, anticancer and antiviral, including action against severe acute respiratory syndrome (SARS) or 3C protease inhibitor. A number of drugs based on this motif have already made it to the market. Standard texts and literature on medicinal chemistry cite different approaches for the synthesis of 5- pyrazolones. The present review provides an insight view to 5-pyrazolone synthesis, their biological profile and structure-activity relationship studies.

From Pyrazolones to Azaindoles: Evolution of Active-Site SHP2 Inhibitors Based on Scaffold Hopping and Bioisosteric Replacement.

The tyrosine phosphatase SHP2 controls the activity of pivotal signaling pathways, including MAPK, JAK-STAT, and PI3K-Akt. Aberrant SHP2 activity leads to uncontrolled cell proliferation, tumorigenesis, and metastasis. SHP2 signaling was recently linked to drug resistance against cancer medications such as MEK and BRAF inhibitors. In this work, we present the development of a novel class of azaindole SHP2 inhibitors. We applied scaffold hopping and bioisosteric replacement concepts to eliminate unwanted structural motifs and to improve the inhibitor characteristics of the previously reported pyrazolone SHP2 inhibitors. The most potent azaindole 45 inhibits SHP2 with an IC50 = 0.031 µM in an enzymatic assay and with an IC50 = 2.6 µM in human pancreas cells (HPAF-II). Evaluation in a series of cellular assays for metastasis and drug resistance demonstrated efficient SHP2 blockade. Finally, 45 inhibited proliferation of two cancer cell lines that are resistant to cancer drugs and diminished ERK signaling.

Novel thiazole-pyrazolone hybrids as potent ACE inhibitors and their cardioprotective effect on isoproterenol-induced myocardial infarction.

A facile synthesis of a group of novel thiazole-pyrazolone hybrids and their investigation for angiotensin-converting enzyme (ACE) inhibition are reported in this study. These compounds were synthesized using a well-known approach, based on the condensation of ethyl acetoacetate with thiazolylhydrazines, and characterized by various spectroscopic and analytical techniques. The entire set of compounds displayed a moderate-to-excellent inhibitory activity against ACE. In particular, compound 4i was found to be the most potent ACE inhibitor and was further studied for cardioprotective effects against isoproterenol (ISO)-induced myocardial infarction (MI) in rats. Compound 4i improved the cardiac function and prevented cardiac injury induced by ISO in Sprague Dawley rats. The levels of oxidative stress and proinflammatory cytokines were also restored to near normal by 4i as compared with the ISO group. In the Western blot analysis, compound 4i prevented mitochondrial apoptosis after MI by downregulating the expression of cleaved caspase-3 and Bax, with the upregulation of Bcl-2, as compared with the ISO group.

Design, synthesis, and biological evaluation of new pyrazoloquinazoline derivatives as dual COX-2/5-LOX inhibitors.

A new series of pyrazoloquinazoline derivatives equipped with different chalcones was designed, synthesized, and identified through 1 H nuclear magnetic resonance (NMR), 13 C NMR, and infrared spectroscopic techniques. Our design strategy of the quinazolinone-privileged scaffold as a new scaffold was based on merging pharmacophores previously reported to exhibit cyclooxygenase-2 (COX-2)/5-lipoxygenase (5-LOX) inhibitory activity. All the newly synthesized derivatives were biologically evaluated for COX and 5-LOX inhibitory activity and COX-2 selectivity, using celecoxib and zileuton as reference drugs, as they exhibited promising anti-inflammatory activity. Compound 3j was found to be the most promising derivative, with IC50 values of 667 and 47 nM against COX-1 and COX-2, respectively, which are superior to that of celecoxib (IC50 value against COX-2 = 95 nM), showing an SI of 14.2 that was much better than celecoxib. Compounds 3f and 3h exhibited COX-1 inhibition, with IC50 values of 1,485 and 684 nM, respectively. The synthesized compounds showed a significant inhibitory activity against 5-LOX, with IC50 values ranging from 0.6 to 4.3 µM, where compounds 3f and 3h were found to be the most potent derivatives, with IC50 values of 0.6 and 1.0 µM, respectively, in comparison with that of zileuton (IC50 = 0.8 µM). These promising derivatives, 3f, 3h, and 3j, were further investigated in vivo for anti-inflammatory, gastric ulcerogenic effects, and prostaglandin production (PGE2) in rat serum. The molecular docking studies concerning the binding sites of COX-2 and 5-LOX revealed similar orientation, compared with reported inhibitors, which encouraged us to design new leads targeting COX-2 and 5-LOX as dual inhibitors, as a new avenue in anti-inflammatory therapy.

Targeting fungal virulence factor by small molecules: Structure-based discovery of novel secreted aspartic protease 2 (SAP2) inhibitors.

Secreted aspartic protease 2 (SAP2), a kind of virulence factor, is an emerging new antifungal target. Using docking-based virtual screening and structure-based inhibitor design, a series of novel SAP2 inhibitors were successfully identified. Among them, indolone derivative 24a showed potent SAP2 inhibitory activity (IC50 = 0.92 µM). It blocked fungi biofilm and hypha formation by down-regulating the expression of genes SAP2, ECE1, ALS3 and EFG1. As a virulence factor inhibitor, compound 24a was inactive in vitro and showed potent in vivo efficacy in a murine model of invasive candidiasis. It represents a promising lead compound for the discovery of novel antifungal agents.

Structure-Activity Relationship of Phenylpyrazolones against Trypanosoma cruzi.

Chagas disease is a neglected parasitic disease caused by the parasitic protozoan Trypanosoma cruzi and currently affects around 8 million people. Previously, 2-isopropyl-5-(4-methoxy-3-(pyridin-3-yl)phenyl)-4,4-dimethyl-2,4-dihydro-3H-pyrazol-3-one (NPD-0227) was discovered to be a sub-micromolar inhibitor (pIC50 =6.4) of T. cruzi. So far, SAR investigations of this scaffold have focused on the alkoxy substituent, the pyrazolone nitrogen substituent and the aromatic substituent of the core phenylpyrazolone. In this study, modifications of the phenyldihydropyrazolone scaffold are described. Variations were introduced by installing different substituents on the phenyl core, modifying the geminal dimethyl and installing various bio-isosteres of the dihydropyrazolone group. The anti T. cruzi activity of NPD-0227 could not be surpassed as the most potent compounds show pIC50 values of around 6.3. However, valuable additional SAR data for this interesting scaffold was obtained, and the data suggest that a scaffold hop is feasible as the pyrazolone moiety can be replaced by a oxazole or oxadiazole with minimal loss of activity.

Synthesis and Cytotoxic Evaluation of Some Substituted 5-Pyrazolones and Their Urea Derivatives.

In this paper, a series of new substituted-5-pyrazolones were first synthesized, then formulated by the Vilsmeier-Haack reaction to obtain substituted-4-carbaldehyde-5-pyrazolones. In the final step, when urea was reacted with formulated pyrazolones, we found that, instead of the C=N bond in azomethine form, the compounds tautomerized to form a series of novel pyrazole-4-ylidenemethylurea structures. The structures of these compounds were elucidated by FTIR, 1H, 13C NMR, LC-MS/MS, and elemental analysis methods. The cytotoxic and antioxidant effects of substituted 5-pyrazolones and their pyrazolone-urea derivatives were investigated in metastatic A431 and noncancerous HaCaT human keratinocytes by a mitochondrial activity test. The effects of the compounds on the migration of cancerous and noncancerous cell lines were investigated by using a cell scratch assay. The General Linear Model, Statistical Package for Social Sciences (SPSS v26) was used to determine if there was a statistically significant difference between the control and the treatment groups. Four of the nine compounds showed an antioxidant effect. All 5-pyrazolone-urea compounds showed higher toxicity (p < 0.05) in cancerous A431 cells compared to noncancerous cells at all time points. All compounds also showed a biphasic hormetic effect. Four of the nine compounds inhibited cell migration.

Synthesis and biological evaluation of pyrazolone analogues as potential anti-inflammatory agents targeting cyclooxygenases and 5-lipoxygenase.

New pyrazolone derivatives structurally related to celecoxib and FPL 62064 were synthesized and biologically evaluated for their inhibitory activity against cyclooxygenases (COXs) and 5-lipoxygenase (5-LOX) and their selectivity indices were calculated. The results showed that compounds 3f, 3h, 3l, and 3p have an excellent COX-2 selectivity index. Moreover, they showed potent 5-LOX inhibitory activity relative to celecoxib and zileuton, as positive controls. These promising candidates were further investigated for anti-inflammatory activity using the carrageenan-induced rat paw edema method and ulcerogenic liability. The results showed no ulceration, which implies their gastric safety profile. Moreover, these compounds were evaluated for prostaglandin (PGE2) production in rat serum. Molecular docking in the COX-2 and 5-LOX active sites was performed to rationalize their anti-inflammatory activities. Strong binding interactions and effective docking scores were identified. The results indicated that these derivatives are good leads for dual-acting COX-2/5-LOX inhibitors to be used as potent and safe anti-inflammatory agents.

Design, synthesis, and evaluation of indeno[2,1-c]pyrazolones for use as inhibitors against hypoxia-inducible factor (HIF)-1 transcriptional activity.

HIF-1 is regarded as a promising target for the drugs used in cancer chemotherapy, and creating readily accessible templates for the development of synthetic drug candidates that could inhibit HIF-1 transcriptional activity is an important pursuit. In this study, indeno[2,1-c]pyrazolones were designed as readily available synthetic inhibitors of HIF-1 transcriptional activity. Nine compounds were synthesized in 4-5 steps from commercially available starting materials. In evaluations of the ability to inhibit the hypoxia-induced transcriptional activity of HIF-1, compound 3c showed a higher level compared with that of known inhibitor, YC-1. The compound 3c suppressed HIF-1α protein accumulation without affecting the levels of HIF-1α mRNA.

Identification of Phenylpyrazolone Dimers as a New Class of Anti-Trypanosoma cruzi Agents.

Chagas disease is becoming a worldwide problem; it is currently estimated that over six million people are infected. The two drugs in current use, benznidazole and nifurtimox, require long treatment regimens, show limited efficacy in the chronic phase of infection, and are known to cause adverse effects. Phenotypic screening of an in-house library led to the identification of 2,2'-methylenebis(5-(4-bromophenyl)-4,4-dimethyl-2,4-dihydro-3H-pyrazol-3-one), a phenyldihydropyrazolone dimer, which shows an in vitro pIC50 value of 5.4 against Trypanosoma cruzi. Initial optimization was done by varying substituents of the phenyl ring, after which attempts were made to replace the phenyl ring. Finally, the linker between the dimer units was varied, ultimately leading to 2,2'-methylenebis(5-(3-bromo-4-methoxyphenyl)-4,4-dimethyl-2,4-dihydro-3H-pyrazol-3-one (NPD-0228) as the most potent analogue. NPD-0228 has an in vitro pIC50 value of 6.4 against intracellular amastigotes of T. cruzi and no apparent toxicity against the human MRC-5 cell line and murine cardiac cells.

Design, synthesis, and biological evaluation of a new class of histone acetyltransferase p300 inhibitors.

p300 is an important histone acetyltransferase in epigenetics, and its overexpression is closely related to various diseases such as cancers. C646 is one of the most representative p300 inhibitors and used in various studies of p300. However, its intrinsic drawbacks such as containing potentially toxic groups prevent it from further development. In order to find potent p300 inhibitors with good drug-like properties, C646 was chosen as the lead compound and a series of new p300 inhibitors were designed based on the principle of bioisosterism and reasonable scaffold hopping, and the structure-activity relationship was systematically explored. Ten of them were found to show comparable inhibitory activity as C646. The most potent compound, 1r (IC50 = 0.16 µM), showed better p300 inhibitory activity than C646 with improved drug-like properties. Western blotting experiment confirmed that 1r could reduce the level of H3K27 acetylation more significantly than C646. Further cellular assay indicated that it could inhibit the proliferation of human breast ductal carcinoma cell T47D and human breast cancer cell MCF7 with the IC50 values of 5.08 µM and 22.54 µM, respectively. Docking study of 1r with p300 protein showed the possible reasons for its higher inhibition activity. Thus, compound 1r might be with potential for development as a novel epigenetic agent targeting p300.

Stereoselective Assembly of Multifunctional Spirocyclohexene Pyrazolones That Induce Autophagy-Dependent Apoptosis in Colorectal Cancer Cells.

Enantio- and diastereoselective synthesis of multifunctional spiropyrazolone scaffolds has been achieved using secondary amine-catalyzed [4 + 2] annulations of α,ß,γ,δ-unsaturated pyrazolones with aldehydes. The pyrazolone substrates serve as C4 synthons to produce 6-membered, carbocycle-based, chiral spiropyrazolone derivatives. The synthesized chiral compounds showed potent toxicity against a panel of cancer cell lines. The most potent compound 3h-induced cell cycle arrest and macroautophagy in HCT116 colorectal cancer cells, triggering autophagy-dependent apoptotic cell death.

Novel Hybrids of Pyrazolidinedione and Benzothiazole as TZD Analogues. Rationale Design, Synthesis and In Vivo Anti-Diabetic Evaluation.

BACKGROUND: The development of new classes of blood glucose-lowering medications has increased the number of treatment opportunities available for type 2 diabetes. Nevertheless, long term complicated treatments and side effects of available antidiabetic therapies have urged huge demands for effective affordable anti-diabetic agents that can lessen negative health consequences. In this sense, the exploration of alternative medicinal remedies associated with new significant antidiabetic efficiencies with minimized adverse effects is an active domain of research. OBJECTIVE: The aim of this study was to synthesize a series of benzothiazole-pyrazolidinedione hybrids and evaluate their antidiabetic activity along with molecular docking and in silico analysis. METHODS: The hybrids were synthesized by a multi-step synthesis and were further subjected for in vivo anti-hyperglycemic assessment on rat models of type II diabetes. Molecular modelling study was undertaken against peroxisome proliferator-activated receptor γ (PPARγ) to highlight possible key interactions. RESULTS: Docking studies revealed that appropriate substituents on benzothiazole ring interacted favorably with the hydrophobic Ω-pocket of PPARγ binding site resulting in improving their antihyperglycemic activity. All the synthesized hybrids manifested promising anti-hyperglycemic potency. Excitingly, 5a, 5b and 5c were even more potent than the standard drug. CONCLUSION: The newly synthesized hybrids can be considered as a new class of antidiabetic agents and this study provided useful information on further optimization.

Nanoformulation of a Novel Pyrano[2,3-c] Pyrazole Heterocyclic Compound AMDPC Exhibits Anti-Cancer Activity via Blocking the Cell Cycle through a P53-Independent Pathway.

Pyrano[2,3-c]pyrazole derivatives have been reported as exerting various biological activities. One compound with potential anti-tumor activity was screened out by MTT assay from series of dihydropyrazopyrazole derivatives we had synthesized before using a one-pot, four-component reaction, and was named as 6-amino-4-(2-hydroxyphenyl)-3-methyl-1,4-dihydropyrano[2,3-c]pyrazole-5-carbonitrile (hereinafter abbreviated as AMDPC). The IC50 of AMDPC against Bcap-37 breast cancer cells was 46.52 µg/mL. Then the hydrophobic AMDPC was encapsulated in PEG-PLGA block copolymers, and then self-assembled as polymeric micelle (mPEG-PLGA/AMDPC) to improve both physiochemical and release profiles. The effect of mPEG-PLGA/AMDPC on BCAP-37 cancer cells showed similar anti-tumor effects as AMDPC. Furthermore, the anti-tumor mechanism of mPEG-PLGA/AMDPC was investigated, which can probably be attributed to stimulating the expression of P21 gene and therefore protein production on BCAP-37 cells, and then blocked the cell cycle through the P53-independent pathway both in S phase and G2 phase. Thus, mPEG-PLGA/AMDPC is a promising therapeutic agent for cancer treatment, and further in vivo studies will be developed.

Investigation of tetrazine reactivity towards C-nucleophiles: pyrazolone-based modification of biomolecules.

Chemoselective, biocompatible ligation reactions are the key components for efficient and modular access to biomolecular scaffolds. Tetrazine ligation leads to the formation of a mixture of isomers, which makes reaction monitoring, purification and characterization of conjugates difficult. We report herein a modified tetrazine ligation strategy based on the use of a pyrazolone coupling partner, which provides a single molecule conjugate.