Pyrazolo[3,4-d]pyrimidines as novel inhibitors of O-acetyl-l-serine sulfhydrylase of Entamoeba histolytica: an in silico study

Investigation of ritonavir analogs antiretroviral natural compounds against SARS-CoV-2 envelope protein

Since the pandemic caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) was first reported from Wuhan, China, there has been a surge in scientific research to find a permanent cure for the disease. The main challenge in effective drug discovery is the continuously mutating nature of the SARS-CoV-2 virus. Thus, we have used the I-TASSER modeling to predict the structure of the SARS-CoV-2 viral envelope protein followed by combinatorial computational assessment to predict its putative potential small molecule inhibitors. As early treatment with ritonavir in combination was associated with faster time to clinical improvement and/or virological clearance, we aimed to retrieve analogs of ritonavir to find ideal inhibitors for SARS-CoV-2 viral envelope protein. The collected ligands were screened against the predicted binding pocket of viral envelope protein using extra precision (XP) docking protocol and the first four best-docked compounds were studied for complex stability using 300 ns all-atom molecular dynamics simulations embedding within the cellular membrane. Among the selected compounds, ZINC64859171 and ZINC1221429 showed considerable stability and interactions by comparison to the reference compound, i.e., Ritonavir (ZINC3944422). Moreover, the post-simulation analysis suggested the considerable binding affinity and induced conformation changes in the respective docked complexes against Ritonavir. Altogether, the obtained results demonstrated the putative potential of screened ritonavir analogs, i.e., ZINC64859171, against the envelope protein of SARS-CoV-2 and can be considered for further drug development in the treatment of the COVID-19 pandemic.Communicated by Ramaswamy H. Sarma.

Screening approach by a combination of computational and in vitro experiments: identification of fluvastatin sodium as a potential SIRT2 inhibitor

BACKGROUND

Sirtuins (SIRTs) are NAD+-dependent deacetylases that play various roles in numerous pathophysiological processes, holding promise as therapeutic targets worthy of further investigation. Among them, the SIRT2 subtype is closely associated with tumorigenesis and malignancies. Dysregulation of SIRT2 activation can regulate the expression levels of related genes in cancer cells, leading to tumor occurrence and metastasis.

METHODS

In this study, we used computer simulations to screen for novel SIRT2 inhibitors from the FDA database, based on which 10 compounds with high docking scores and good interactions were selected for in vitro anti-pancreatic cancer metastasis testing and enzyme binding inhibition experiments. The results showed that fluvastatin sodium may possess inhibitory activity against SIRT2. Subsequently, fluvastatin sodium was subjected to molecular docking experiments with various SIRT isoforms, and the combined results from Western blotting experiments indicated its potential as a SIRT2 inhibitor. Next, molecular docking, molecular dynamics (MD) simulations, and binding free energy calculations were performed, revealing the binding mode of fluvastatin sodium at the SIRT2 active site, further validating the stability and interaction of the ligand-protein complex under physiological conditions.

RESULTS

Overall, this study provides a systematic virtual screening workflow for the discovery of SIRT2 activity inhibitors, identifies the potential inhibitory effect of fluvastatin sodium as a lead compound on SIRT2, and opens up a new direction for developing highly active and selectively targeted SIRT2 inhibitors.

Targeting the cysteine biosynthesis pathway in microorganisms: Mechanism, structure, and drug discovery

Owing to the global health crisis of resistant pathogenic infections, researchers are emphasizing the importance of novel prevention and control strategies. Existing antimicrobial drugs predominantly target a few pathways, and their widespread use has pervasively increased drug resistance. Therefore, it is imperative to develop new antimicrobial drugs with novel targets and chemical structures. The de novo cysteine biosynthesis pathway, one of the microbial metabolic pathways, plays a crucial role in pathogenicity and drug resistance. This pathway notably differs from that in humans, thereby representing an unexplored target for developing antimicrobial drugs. Herein, we have presented an overview of cysteine biosynthesis pathways and their roles in the pathogenicity of various microorganisms. Additionally, we have investigated the structure and function of enzymes involved in these pathways as well as have discussed drug design strategies and structure-activity relationships of the enzyme inhibitors. This review provides valuable insights for developing novel antimicrobials and offers new avenues to combat drug resistance.

Synthesis and Exploration of New Imidazo[4,5‐c]Pyrazoles as Potent α‐Amylase Inhibitors

To identify new leads of small molecules as α‐amylase inhibitors, the current research is focused on the assessment of imidazopyrazoles. Hence, a set of novel imidazo[4,5‐c]pyrazoles was synthesized via simple versatile straightforward synthetic routes and was estimated for their in vitro α‐amylase inhibition activity. The findings revealed that diphenylaminomethyl and phenylcarbamodithioate derivatives elicited potent α‐amylase inhibition activities with IC50 values of 0.071 and 0.083 μM, respectively that were comparable to acarbose (IC50 0.060 μM). Molecular docking and in silico studies were performed for the most active derivatives and demonstrated that docked compounds have good binding affinities toward α‐amylase with binding free energies that are very similar to that of acarbose. Furthermore, these compounds demonstrated not only significant biological activity but also noteworthy physicochemical properties, drug‐likeness, and good pharmacokinetics. As a result, such compounds offered a robust opportunity for further development and optimization of the imidazopyrazole scaffold for the potential management of Type II Diabetes Mellitus.

Design of ionic liquids containing glucose and choline as drug carriers, finding the link between QM and MD studies

Designing drug delivery systems for therapeutic compounds whose receptors are located in the cytosol of cells is challenging as a bilayer cell membrane is negatively charged. The newly designed drug delivery systems should assist the mentioned drugs in passing the membrane barriers and achieving their targets. This study concentrated on developing novel ionic liquids (ILs) that interact effectively with cell membranes. These ILs are based on glucose-containing choline and are expected to be non-toxic. The binding energies of the known pharmaceutically active ionic liquids were calculated at the B3LYP/6-311++G(d,p) level in the gas phase and compared with those of our newly designed carbohydrate-based ionic liquids. Subsequently, we employed MD simulations to obtain information about the interactions of these known and designed ILs with the cell membrane. In our approach, we adopted QM and MD studies and illustrated that there could be a link between the QM and MD results.

Elucidation of the inhibitory activity of plant-derived SARS-CoV inhibitors and their potential as SARS-CoV-2 inhibitors

Several drugs are now being tested as possible therapies due to the necessity of treating SARS-CoV-2 infection. Although approved vaccines bring much hope, a vaccination program covering the entire global population will take a very long time, making the development of effective antiviral drugs an effective solution for the immediate treatment of this dangerous infection. Previous studies found that three natural compounds, namely, tannic acid, 3-isotheaflavin-3-gallate and theaflavin-3,3-digallate, are effective proteinase (3CL^pro) inhibitors of SARS-CoV (IC₅₀ <10 µM). Based on this information and due to the high sequence identity between SARS-CoV and SARS-CoV-2 3CL^pro, these three compounds could be candidate inhibitors of SARS-CoV-2 3CL^pro. This paper explores the structural and energetic features that guided the molecular recognition of these three compounds for dimeric SARS-CoV-2 and SARS-CoV 3CL^pro, the functional state of this enzyme, using docking and MD simulations with the molecular mechanics-generalized-born surface area (MMGBSA) approach. Energetic analysis demonstrated that the three compounds reached good affinities in both systems in the following order: tannic acid > 3-isotheaflavin-3-gallate > theaflavin-3,3-digallate. This tendency is in line with that experimentally reported between these ligands and SARS-CoV 3CL^pro. Therefore, tannic acid may have clinical usefulness against COVID-19 by acting as a potent inhibitor of SARS-CoV-2 3CL^pro.Communicated by Ramaswamy H. Sarma.

Design of amino acid- and carbohydrate-based anticancer drugs to inhibit polymerase η

DNA polymerase η (polη) is of significant value for designing new families of anticancer drugs. This protein takes a role in many stages of the cell cycle, including DNA replication, translesion DNA synthesis, and the repairing process of DNA. According to many studies, a high level of expression of polη in most cases has been associated with low rates of patients' survival, regardless of considering the stage of tumor cells. Thus, the design of new drugs with fewer side effects to inhibit polη in cancerous cells has attracted attention in recent years. This project aims to design and explore the alternative inhibitors for polη, which are based on carbohydrates and amino acids. In terms of physicochemical properties, they are similar to the traditional anticancer drugs such as Cytarabine (cytosine arabinose). These alternative inhibitors are supposed to disrupt the DNA replication process in cancerous cells and prevent the tumor cells from mitosis. These newly designed structures, which are based on natural products, are expected to be non-toxic and to have the same chemotherapeutic impact as the traditional agents. The combinatorial use of quantum mechanics studies and molecular dynamic simulation has enabled us to precisely predict the inhibition mechanism of the newly designed structure, which is based on carbohydrates and amino acids, and compare it with that of the traditional chemotherapeutic drugs such as Cytarabine. Our results suggest that the inhibitors containing the natural building blocks of amino acid and carbohydrate could be considered alternative drugs for Cytarabine to block polη.

Exploring dual agonists for PPARα/γ receptors using pharmacophore modeling, docking analysis and molecule dynamics simulation

BACKGROUND

The peroxisome proliferator-activated receptors (PPARs) are ligand-activated transcription factors belonging to the nuclear receptor family. The roles of PPARα in fatty acid oxidation and PPARγ in adipocyte differentiation and lipid storage have been widely characterized. Compounds with dual PPARα/γ activity have been proposed, combining the benefits of insulin sensitization and lipid-lowering into one drug, allowing a single drug to reduce hyperglycemia and hyperlipidemia while preventing the development of cardiovascular complications.

METHODS

The new PPARα/γ agonists were screened through virtual screening of pharmacophores and molecular dynamics simulations. First, in the article, the constructed pharmacophore was used to screen the Ligand Expo Components-pub database to obtain the common structural characteristics of representative PPARα/γ agonist ligands. Then, the obtained ligand structure was modified and replaced to obtain 12 new compounds. Using molecular docking, ADMET and molecular dynamics simulation methods, the designed 12 ligands were screened, their docking scores were analyzed when they bound to the PPARα/γ dual targets, and also their stability and pharmacological properties were assessed when they were bound to the PPARα/γ dual targets.

RESULTS

We performed pharmacophore-based virtual screening for 22949 molecules in the Ligand Expo Components-pub database. Structural analysis and modification were performed on the compounds that were superior to the original ligand , and a series of compounds with novel structures were designed. Using precise docking, ADMET prediction and molecular dynamics methods, newly designed compounds were screened and verified, and the above compounds showed higher docking scores and lower side effects.

CONCLUSION

9 new PPARα/γ agonists were obtained by pharmacophore modeling, docking analysis and molecule dynamics simulation.

Design of carboxylate-based ionic liquids (ILs) containing OH and CF3 groups; influence of intramolecular hydrogen bonds and inductive effect on the binding energy between the cation and anion of ILs, a DFT study

Ionic liquids, which are widely known as room temperature molten salts, have been the subject of much scientific debate for more than a decade.

Speculative analysis on the electronic structure, IR assignments and molecular docking of N-{4-[(4-amino-3-phenyl-1H-pyrazolo[3,4-d]pyrimidin-1-yl)sulfonyl]phenyl}acetamide, an anti-amoebic agent

An exhaustive quantum mechanical calculations on a pharmaceutically critical molecule N-{4-[(4-amino-3-phenyl-1H-pyrazolo[3,4-d]pyrimidin-1-yl)sulfonyl]phenyl}acetamide have been investigated through the B3LYP/6-31G∗∗ Density Functional and HF/6-31G∗∗ Wave Function techniques. Physicochemical parameters along with the advanced electronic structure parameters like; MEP (molecular electrostatic potentials) and highest occupied & lowest unoccupied molecular orbitals (HOMO-LUMO) analysis have additionally been scanned over both methods. The computed HOMO-LUMO energy demonstrates that charge exchange takes place inside the molecule. The estimated small HOMO-LUMO energy gap, through both methods, indicates that the molecule is chemically reactive. Further, the IR vibrational spectra of the molecule have been assigned in the region 400-4000 cm⁻¹ through the DFT technique. The anticipated vibrational assignments have been compared with the experimental values accounted for in the literature. To comprehend the mode of binding, docking investigations of the molecule alongwith the co-crystallized metronidazole (MNZ) molecule were accomplished with O-acetyl-serine-sulfhydrylase (OASS) enzyme using GLIDE-SP and GLIDE-XP modules. Docking simulations and reported biological activities (IC50) demonstrate that the title molecule may act as a lead molecule for constraining the progression of Entamoeba histolytica illness.

Synthesis, Characterization, Antimicrobial Activity and Anticancer of Some New Pyrazolo[1,5-a]pyrimidines and Pyrazolo[5,1-c]1,2,4-triazines

BACKGROUND

Pyrazole and its derivatives are known to exhibit significant biological and pharmacological activities such as anticancer, anti-inflammatory, antioxidant, antibacterial, analgesic, antiviral, antimicrobial, antifungal, anti-glycemic, antiamoebic, and antidepressive. Considering the immense biological properties, pyrazole is one of the most widely studied nitrogen- containing heterocyclic nuclei. Fused pyrazole derivatives are composed of the pyrazole nucleus attached to other heterocyclic moieties.

OBJECTIVE

The objective of this article is the synthesis of some new pyrazolo[1,5-a]pyrimidine and pyrazolo[5,1-c]1,2,4-triazine derivatives with potential anticancer and antimicrobial activities.

METHODS

The in vitro growth inhibitory rates (%) and inhibitory growth activity (as measured by IC50) of the newly synthesized compounds were determined against the MCF-7 human breast carcinoma cell line in comparison with the well-known anticancer drug doxorubicin as the standard, using the MTT viability assay. The data generated were used to plot a dose-response curve from which the concentration (μM) of tested compounds required to kill 50% of the cell population (IC50) was determined. Cytotoxic activity was expressed as the mean IC50 of three independent experiments. The difference between inhibitory activities of all compounds with different concentrations was statistically significant p < 0.001. All compounds were structurally characterized by different spectroscopic techniques EI-MS, 1H-NMR, and 13C-NMR, and evaluated for their anticancer and antimicrobial activities (antibacterial and antifungal).

RESULTS

Several pyrazolo[1,5-a]pyrimidine derivatives were synthesized from the reaction of 2-(4- (5-amino-1H-pyrazol-3-yl)phenyl)-1H-indene-1,3(2H)-dione with the appropriate active methylene compounds in boiling ethanol. Also, pyrazolo[5,1-c]triazines were obtained through the reaction of 2-(4-(5-(chlorodiazenyl)-1H-pyrazol-3-yl)phenyl)-1H-indene-1,3(2H)-dione with various active methylene compounds in ethanol containing sodium acetate at 0-5 oC. The structures of the newly synthesized compounds were elucidated on the basis of elemental analysis, spectral data, and alternative synthetic routes whenever possible. The newly synthesized compounds were evaluated for their antitumor activity against a breast cancer cell line (MCF-7) and a human colon cancer cell line (HCT-116). The results revealed that the tested compounds showed high variation in the inhibitory growth rates and activities against the tested tumor cell lines. All newly synthesized compounds screen towards microorganisms e.g. Gram-negative bacteria, Gram-positive bacteria, and Fungi.

CONCLUSION

2-(4-(5-Amino-1H-pyrazol-3-yl)phenyl)isoindoline-1,3-dione proved to be a useful precursor for the synthesis of various pyrazolo[1,5-a]pyrimidine and pyrazolo[5,1-c]-1,2,4- triazines. The structures of the newly synthesized compounds were confirmed by spectral data and elemental analyses. The newly synthesized compounds were tested in vitro against the MCF-7, HCT-116 human cancer cell line and compared with doxorubicin as the standard, using the MTT viability assay. Most of the tested compounds were found to have moderate to high anticancer activity.

Insights into multifaceted activities of CysK for therapeutic interventions

CysK (O-acetylserine sulfhydrylase) is a pyridoxal-5' phosphate-dependent enzyme which catalyzes the second step of the de novo cysteine biosynthesis pathway by converting O-acetyl serine (OAS) into l-cysteine in the presence of sulfide. The first step of the cysteine biosynthesis involves formation of OAS from serine and acetyl CoA by CysE (serine acetyltransferase). Apart from role of CysK in cysteine biosynthesis, recent studies have revealed various additional roles of this enzyme in bacterial physiology. Other than the suggested regulatory role in cysteine production, other activities of CysK include involvement of CysK-in contact-dependent toxin activation in Gram-negative pathogens, as a transcriptional regulator of CymR by stabilizing the CymR-DNA interactions, in biofilm formation by providing cysteine and via another mechanism not yet understood, in ofloxacin and tellurite resistance as well as in cysteine desulfurization. Some of these activities involve binding of CysK to another cellular partner, where the complex is regulated by the availability of OAS and/or sulfide (H₂S). The aim of this study is to present an overview of current knowledge of multiple functions performed by CysK and identifying structural features involved in alternate functions. Due to possible role in disease, promoting or inhibiting a "moonlighting" function of CysK could be a target for developing novel therapeutic interventions.

Discovery of Antiamebic Compounds That Inhibit Cysteine Synthase From the Enteric Parasitic Protist Entamoeba histolytica by Screening of Microbial Secondary Metabolites

Amebiasis is caused by infection with the protozoan parasite Entamoeba histolytica. Although metronidazole has been a drug of choice against amebiasis for decades, it shows side effects and low efficacy against asymptomatic cyst carriers. In addition, metronidazole resistance has been documented for bacteria and protozoa that share its targets, anaerobic energy metabolism. Therefore, drugs with new mode of action or targets are urgently needed. L-cysteine is the major thiol and an essential amino acid for proliferation and anti-oxidative defense of E. histolytica trophozoites. E. histolytica possesses the de novo L-cysteine biosynthetic pathway, consisting of two reactions catalyzed by serine acetyltransferase and cysteine synthase (CS, O-acetylserine sulfhydrylase). As the pathway is missing in humans, it is considered to be a rational drug target against amebiasis. In this study, we established a protocol to screen both a library of structurally known compounds and microbial culture extracts to discover compounds that target de novo cysteine biosynthesis of E. histolytica. The new screening system allowed us to identify the compounds that differentially affect the growth of the trophozoites in the cysteine-deprived medium compared to the cysteine-containing medium. A total of 431 structurally defined compounds of the Kitasato Natural Products Library and 6,900 microbial culture broth extracts were screened on the system described above. Five compounds, aspochalasin B, chaetoglobosin A, prochaetoglobosin III, cerulenin, and deoxyfrenolicin, from the Kitasato Natural Products Library, showed differential antiamebic activities in the cysteine-deprived medium when compared to the growth in the cysteine-containing medium. The selectivity of three cytochalasans apparently depends on their structural instability. Eleven microbial extracts showed selective antiamebic activities, and one fungal secondary metabolite, pencolide, was isolated. Pencolide showed cysteine deprivation-dependent antiamebic activity (7.6 times lower IC50 in the absence of cysteine than that in the presence of cysteine), although the IC50 value in the cysteine-deprived medium was rather high (283 μM). Pencolide also showed inhibitory activity against both CS1 and CS3 isoenzymes with comparable IC50 values (233 and 217 μM, respectively). These results indicated that antiamebic activity of pencolide is attributable to inhibition of CS. Cytotoxicity of pencolide was 6.7 times weaker against mammalian MRC-5 cell line than E. histotytica. Pencolide has the maleimide structure, which is easily attacked by Michael donors including the thiol moiety of cysteine. The cysteine-adducts of pencolide were detected by mass spectrometric analysis as predicted. As CS inhibition by the pencolide adducts was weak and their IC50 values to CS was comparable to that to the parasite in the cysteine-containing medium, the cysteine-adducts of pencolide likely contribute to toxicity of pencolide to the parasite in the cysteine-rich conditions. However, we cannot exclude a possibility that pencolide inactivates a variety of targets other than CSs in the absence of cysteine. Taken together, pencolide is the first compound that inhibits CS and amebic cell growth in a cysteine-dependent manner with relatively low mammalian cytotoxicity.

Synthesis and mechanistic studies of diketo acids and their bioisosteres as potential antibacterial agents

A series of diketo esters and their pertinent bioisosteres were designed and synthesized as potent antibacterial agents by targeting methionine amino peptidases (MetAPs). In the biochemical assay against purified MetAPs from Streptococcus pneumoniae (SpMetAP1a), Mycobacterium tuberculosis (MtMetAP1c), Enterococcus faecalis (EfMetAP1a) and human (HsMetAP1b), compounds 3a, 4a and 5a showed more than 85% inhibition of all the tested MetAPs at 100 μM concentration. Compounds 4a and 5a also exhibited antibacterial potential with MIC values 62.5 μg/mL (S. pneumoniae), 31.25 μg/mL (E. faecalis), 62.5 μg/mL (Escherichia coli) and 62.5 μg/mL (S. pneumoniae), 62.5 μg/mL (E. coli), respectively. Moreover, 5a also significantly inhibited the growth of multidrug resistant E. coli strains at 512 μg/mL conc., while showing no cytotoxic effect towards healthy CHO cells and thus being selected. Growth kinetics study showed significant inhibition of bacterial growth when treated with different conc. of 5a. TEM analysis also displayed vital damage to bacterial cells by 5a at MIC conc. Moreover, significant inhibition of biofilm formation was observed in bacterial cells treated with MIC conc. of 5a as visualized by SEM micrographs. Interestingly, 5a did not cause an alteration in the hemocyte density in Galleria mellonella larvae which is considered in vivo model for antimicrobial studies and was non-toxic up to a conc. of 2.5 mg/mL.

Identification of isobavachalcone as a potential drug for rice blast disease caused by the fungus Magnaporthe grisea

The rice blast disease caused by the fungus Magnaporthe grisea is one of the most devastating rice diseases, but there is no effective fungicide toward chitinase which is a key enzyme of M. grisea. In this study, we observed that distortion and cell-wall damage of M. grisea hyphae were significantly under the scanning electron micrograph after a 24-h treatment with 10 mg/L isobavachalcone (IBC) extracted from Psoralea corylifolia L. To further explore the effect of IBC on the cell wall of M. grisea, we examined changes in enzymes associated with cell wall degradation by enzyme activity experiments, treated liquid culture mycelia with 10 mg/L IBC for 1 h. Results displayed that chitinase was obviously more active than control group. To illustrate the interactions between IBC and chitinase, the studies of homology modeling and molecular docking were carried out successively. The results revealed that IBC had hydrogen bonds with residues ASP267 and ARG276 of chitinase. Besides, these nonpolar residues TYR270, PRO271, VAL272, LEU310, PRO311, TYR316, and LEU317 were able to form strong hydrophobic interactions. Binding energies of the chitinase-IBC complexes were calculated by MM-GBSA showed that the ΔG_bind score of molecular dynamics had lower binding energy and more stable than docking complexes. All above, IBC owns significant agonistic activity in chitinase and would be a potent fungicide to inhibit the growth of M. grisea. We hope the above information provides an important insight for understanding the interactions between IBC and chitinase, which may be useful in the discovery of a novel potent agonist. Communicated by Ramaswamy H. Sarma.

Computational investigation of TGF-β receptor inhibitors for treatment of idiopathic pulmonary fibrosis: Field-based QSAR model and molecular dynamics simulation

The discovery of drugs relevant to transforming growth factor β (TGF-β) receptor inhibitors have been considered as a considerable challenge during therapy idiopathic pulmonary fibrosis diseases. For the first time, herein we illustrate a field-based quantitative structure-activity relationship (QSAR) model and molecular dynamics (MD) simulations for novel 7-substituted-pyrazolo [4, 3-b] pyridine derivatives with biological activity for the TGF-β receptor, with an attempt of elucidating the 3D structural features that are essential for the activity. Results demonstrate that the field-based model (Q² = 0.548, R²_training = 0.840, R²_test = 0.750) are acceptable with good predictive capabilities. In addition, MD studies were also carried out on the training set with the aim of exploring their binding modes in the active pocket of TGF-β receptor, resulting in some of the crucial structural fragments which are responsible for inhibitory activity. Therefore, we summarized the following features required for TGF-β receptor inhibition: electronegative in region1, bulky groups in region2 and smaller groups in region3. Based on the model and related information, we hope the above information provides an important insight for understanding the interactions of the inhibitors and TGF-β receptor, which may be useful in discovering novel potent inhibitors.

5-Aminopyrazole as precursor in design and synthesis of fused pyrazoloazines

The condensation of 5-aminopyrazole with various bielectrophilic moieties results in the formation of pyrazoloazines, an interesting array of fused heterocyclic systems. The development of new synthetic routes towards pyrazoloazines for their biological and medicinal exploration is an attractive area for researchers throughout the world. The present review focuses on various synthetic methods developed in the last decade for the synthesis of differently substituted pyrazoloazines by a broad range of organic reactions by means of 5-aminopyrazole as a precursor.

Design, sythesis and evaluation of a series of 3- or 4-alkoxy substituted phenoxy derivatives as PPARs agonists

Peroxisome proliferators-activated receptors (PPARα, γ and δ) are potentially effective targets for Type 2 diabetes mellitus therapy. The severe effects of known glitazones and the successfully approved agents (saroglitazar and lobeglitazone) motivated us to study novelly potent PPARs drugs with improved safety profile. In this work, we received 15 carboxylic acids based on the combination principle to integrate the polar head of bezafibrate with the hydrophobic tail of pioglitazone. Another 12 tetrazoles based on the bioisosterism principle were obtained accordingly. Furthermore, in vitro PPARs transactivation assays on these 3- or 4-alkoxy substituted phenoxy derivatives afforded six compounds. Interactions and binding stability from the docking analysis and 20 ns molecular dynamic simulations confirmed the representative compounds to be suitable and plausible for PPARs pockets. The above-mentioned results demonstrated that the compounds may be used as reference for further optimization for enhanced PPARs activities and wide safety range.

Identification of dual ligands targeting angiotensin II type 1 receptor and peroxisome proliferator-activated receptor-γ by core hopping of telmisartan

It has been reported previously that some angiotensin II receptor blockers not only antagonize angiotensin II type 1 receptor (AT₁R), but also exert stimulation in peroxisome proliferator-activated receptor γ (PPARγ) partial activation, among which telmisartan displays the best. Telmisartan has been tested as a bifunctional ligand with antihypertensive and hypoglycemic activity. Aiming at more potent leads with selective AT₁R antagonism and PPARγ partial agonism, the three parts of telmisartan including the distal benzimidazole ring, the biphenyl moiety, and the carboxylic acid group experienced modification by core hopping method in our study. The central benzimidazole ring, however, remained intact considering its great affinity toward AT₁R and PPARγ. We utilized computational techniques for the sake of details on the binding interactions and conformational stability. Standard precision docking analysis and absorption, distribution, metabolism, excretion, and toxicity prediction received 10 molecules with higher Glide scores, similar interactions, and improved pharmacokinetic profiles compared to telmisartan. Comp#91 with highest scores for AT₁R (-11.92 kcal/mol) and PPARγ (-13.88 kcal/mol) exhibited excellent binding modes and pharmacokinetic parameters. Molecular dynamics trajectories on best docking pose of comp#91 confirmed the docking results and verified the conformational stability with both receptors throughout the course of 20-ns simulations. Thus, comp#91 could be identified as a promising lead in the development of dual AT₁R antagonist and PPARγ partial agonist against hypertension and type 2 diabetes.