Potential Pharmacophore Research Articles

Selective C-C Bond Scission of Ketones via Visible-Light-Mediated Cerium Catalysis

Summary Here, we report a general catalytic manifold for the selective C–C bond scission of ketones via the exploitation of the ligand-to-metal charge transfer (LMCT) excitation mode. Through a cooperative utilization of Lewis acid catalysis and LMCT catalysis, the C–C bond of ketones could be selectively and effectively cleaved, enabling the installation of different functionalities at each carbon of the cleaved C–C bond through a sequential and orthogonal manner. This reaction manifold serves as a photocatalytic alternative to the Norrish type I reaction with the combination of visible light and inexpensive cerium salts. Under operationally simple conditions, a wide range of acyclic and cyclic ketones, from simple strained cyclobutanones to complex androsterone with less strained cyclopentanone moiety, could be successfully transformed into versatile chemical building blocks.

Synthesis and antitumor activity of bis(arylsulfonyl)dihydroimidazolinone derivatives

A series of novel bis(arylsulfonyl)dihydroimidazolinones with different aryl substitution patterns were readily synthesized and evaluated for their antitumor activities. Some of the newly synthesized compounds exhibited cytotoxicity at micromolar range against multiple cancer cell lines, including A549, HepG2, HuCCA-1, and MOLT-3. The most potent analogue contained pentafluorobenzenesulfonyl groups, which could be chemically elaborated to serve as a potential pharmacophore.

Boiled Abalone Byproduct Peptide Exhibits Anti-Tumor Activity in HT1080 Cells and HUVECs by Suppressing the Metastasis and Angiogenesis in Vitro.

Abalone (Haliotis discus hannai) is a precious seafood in the market. It has been reported that biological active substances derived from abalone have anti-oxidative, anti-inflammatory, anti-bacterial, and anti-thrombosis potential. However, there were few studies to assess whether they have anti-cancer potential. In this study, we evaluated the anti-metastasis and anti-pro-angiogenic factors and mechanism of action of boiled abalone byproduct peptide (BABP, EMDEAQDPSEW) in human fibrosarcoma (HT1080) cells and human umbilical vein endothelial cells (HUVECs). The results demonstrated that BABP treatment significantly lowers migration and the invasion of HT1080 cells and HUVECs. BABP inhibits phorbol 12-myristate 13-acetate (PMA)-induced matrix metalloproteinase (MMP) expression and activity by blocking mitogen-activated protein kinases (MAPKs) and NF-κB signaling and hypoxia-induced vascular endothelial growth factor (VEGF) secretion and hypoxia inducible factor (HIF)-1α accumulation through suppressing the AKT/mTOR signal pathway. BABP treatment inhibits VEGF-induced VEGFR-2 expression and tube formation in HUVECs. The effect of BABP on anti-metastatic and anti-vascular activity in HT1080 cells and HUVECs revealed that BABP may be a potential pharmacophore for tumor therapy in the future.

In silico and in vitro evaluation of tetrahydropyridine compounds as efflux inhibitors in Mycobacterium abscessus

Herein, we evaluated tetrahydropyridine (THP) compounds (NUNM) as antimicrobials and inhibitors of the efflux mechanism in M. abscessus. subsp. abscessus. The modulation factor (MF) of efflux inhibitors was calculated from the minimum inhibitory concentrations (MICs) of amikacin (AMI), ciprofloxacin (CIP) and clarithromycin (CLA) in the absence and presence of subinhibitory concentrations of the NUNM compounds and canonical inhibitors carbonyl cyanide m-chlorophenyl hydrazone (CCCP) and verapamil (VP). The kinetics of the intracellular accumulation of the fluorimetric substrate ethidium bromide (EtBr) was evaluated and calculated by the relative final fluorescence (RFF). In addition, molecular modeling simulations for the MmpL5 and Tap efflux transporters with ligands (CLA, NUNM, CCCP, VP and EtBr) were performed to better understand the efflux mechanism. We highlight the NUNM01 compound because it reduced the MICs of AMI, CIP and CLA by 4-, 4- and 16-fold, respectively, had the highest effect on EtBr accumulation (RFF = 3.1) and showed a significant in silico affinity for the evaluated proteins in docking simulations. Based on the analyses performed in vitro and in silico, we propose that NUNM01 is a potential pharmacophore candidate for the development of a therapeutic adjuvant for M. abscessus infections.

One-pot multicomponent construction of chromanone-fused pyrrolidinyl spirooxindole collections through a decarboxylative 1,3-dipolar [3 + 2] cycloaddition reaction

A new method was developed for the facile one-pot multicomponent construction of heterocycle-fused spiro compounds containing chromanone and pyrrolidinyl spirooxindoles, two potential pharmacophores, in one molecule through a decarboxylative 1,3-dipolar [3 + 2] cycloaddition reaction of carboxylic acid group-activated chromones 1 with isatin-derivated azomethine ylides based on molecular hybridization strategy. A wide variety of products with three contiguous stereocenters including a spiro quaternary stereocenter were smoothly prepared with high efficiency (up to 87% yield and 20:1 diastereomeric ratio). This method could offer libraries of architecturally diverse and multiple pharmacore collections, potentially useful in medicinal chemistry.

Novel highly functionalized 1,4-naphthoquinone 2-iminothiazole hybrids: Synthesis, photophysical properties, crystal structure, DFT studies, and anti(myco)bacterial/antifungal activity

In this paper, a series of novel highly functionalized 1,4-naphthoquinone 2-iminothiazole hybrids were synthesized via a cyclization reaction of 2,3-diaminonaphthalene-1,4-dione N-aroylthioureas and α-bromoketones in good to excellent yields (74–94%). The stereochemistry of one of the 1,4-naphthoquinone 2-iminothiazole products was characterized by single crystal X-ray diffraction technique. Photophysical properties of the compounds in DMSO, HAc and THF were determined by using UV-vis spectroscopy. The ground state geometries and the absorption spectra of the compounds were also determined using Density Functional Theory (DFT) and time-dependent DFT (TD-DFT) at B3LYP/631 + g(d,p) level of theory. The computed results are consistent with experimental values. An antimicrobial screening was performed against various bacterial (S. aureus, B. subtilis, A. hydrophila, E. coli and A. baumannii), fungal (C. glabrata C. tropicalis and C. albicans) and mycobacterial (M. tuberculosis H37Rv) strains. The compounds exhibited moderate antibacterial (62.5–500 μg/mL) and antifungal (31.25–250 μg/mL) activities against the aforementioned bacterial and fungal strains. Two of the compounds, 7j (3.90 μg/mL) and 7l (1.96 μg/mL), exhibited a significant antimycobacterial activity against the M. tuberculosis H37Rv strain, when compared to the reference drugs (Isoniazid: 0.98 μg/mL, Ethambutol: 1.96 μg/mL). The results showed that these novel 1,4-naphthoquinone 2-iminothiazole hybrids can be considered as potential pharmacophore groups for the development of new antimycobacterial agents.

The Outliers: Metal-Mediated Radical Reagents for Biological Substrate Degradation.

The predictable and controllable interaction of small organic or peptidic molecules with biological substrates is the primary reason most pharmaceuticals are narrowly decorated carbon frameworks. The inhibition or activation binding models are measurable and without side reactions that can cause pathological angst. Yet many diseases, especially those involving rapid proliferation of cells (i.e., cancer) or aggregation of peptides (e.g., heart disease, Alzheimer's disease) have not yet been cured by inhibition therapeutics. Additionally, interventional medicine is often required to alleviate such maladies by physical removal first, followed by molecular-level therapy as a second stage. Thus, there appears to be a niche for more aggressive therapeutics that may employ harsher chemical processes to realize clinical efficacy, albeit without causing catastrophic side effects. Molecules that may be considered for this challenge are not typically biomimetic, nor do they fit the traditional pharmaceutical paradigm. They may have unusual modes of action or undesired reactivity that can be lethal if not controlled. These are the outliers; potential pharmacophores that biology does not know how to manage or adapt to. This is why they may be an intriguing class of agents that needs continuous development. In this Account, we connect the under-developed enediyne family of compounds and our metalloenediyne derivatives to existing radical-based therapeutics such as bleomycin and doxorubicin to illustrate that controlled diradical reactivity, although an outlier mechanism, has a place in the therapeutic portfolio. This is self-evident in that of the 11 natural product enediynes known, 2 have clinical impact, a strong ratio. We expand on the chemical diversity of potential enediyne constructs and focus on the accessible trigger mechanisms to activate diradical formation as a method to control toxicity. Moreover, we further illustrate how electromagnetic fields can be employed to activate both molecular and larger nanomaterial constructs that carry highly concentrated payloads of reactive reagent. Finally, we describe how controlled diradical reactivity can reach beyond traditional therapeutic targets such as DNA, to peptide aggregates found in blood clots, neural fibrils, and membrane scaffolds. It is our belief that cleverly constructed frameworks with well-designed and controlled activation/reaction schemes can lead to novel therapeutics that can challenge evolving viral and bacterial invaders. From this evangelical perspective, our hope is that the conceptual framework, if not the specific designs in this Account, stimulate the readership to develop out-of-the-box therapeutic designs that may combat resistant disease targets.

The Methylene-Cycloalkylacetate (MCA) Scaffold in Terpenyl Compounds with Potential Pharmacological Activities

Recently, the methylene-cycloakylacetate (MCA) scaffold has been reported as a potential pharmacophore for neurite outgrowth activity. In this work, natural diterpenes that embed MCA fragments are reviewed, as they are major components of Halimium viscosum: ent-halimic acid, the prototype for these bioactive compounds. Herein, structures, sources, and activities for the natural diterpenes, as well as their synthetic derivatives of interest, are reviewed.

First report of substituted 2H-pyranoids from brown seaweed Turbinaria conoides with antioxidant and anti-inflammatory activities

The organic extract of Turbinaria conoides, a brown seaweed harvested from the Gulf of Manner region of Indian peninsular was chromatographically fractionated to yield three substituted 2H-pyranoids, namely methyl-21-yl-[5′, 6′- dihydro-5′-yl-{54-(4-hydroxybenzoyl)-oxy-(52-methylbutyl)}-3′-methyl-2H-pyran]-21-methyl butanoate (1), 11-[(3′, 6′-dihydro-4′-methyl-2′-oxo-2H-pyran-3′-yl)methyl]-10-methylhexyl benzoate (2), and [6-ethyl-3,4-dimethyl-(tetrahydro-2′, 2′, 6′-trimethyl-2H-pyran-3′-yl)-2,5-cycloheptadiene]-1-propanoate (3). The compounds 1 and 2 bearing 2H-pyranyl-4-hydroxybenzoyl and 2H-pyranyl-10-methylhexylbenzoate moieties exhibited potential antioxidant activities (IC50 0.54-0.69 mg mL−1) as commercial antioxidant (α-tocopherol IC50 0.63-0.73 mg mL−1). Likewise, potential bioactivity of the 2H-pyran derivative, 1 against 5-lipoxygenase (IC50 ∼ 1 mg mL−1) along with higher index of selectivity (COX-1 inhibitoryIC50/COX-2 inhibitoryIC50 1.88) indicated their selective anti-inflammatory properties against inducible inflammatory mediators than that displayed by commercially available non-steroidal anti-inflammatory drug (ibuprofen, 0.44). Structure activity relationship analysis of the studied compounds showed that the antioxidative and anti-inflammatory properties were directly proportional to their electronic properties. The previously undescribed 2H-pyranoids might constitute as potential antioxidative and anti-inflammatory pharmacophores for medicinal applications.

Synthesis, Molecular Modeling and Biological Evaluation of 5-arylidene-N,N-diethylthiobarbiturates as Potential α-glucosidase Inhibitors.

Barbituric acid derivatives are a versatile group of compounds which are identified as potential pharmacophores for the treatment of anxiety, epilepsy and other psychiatric disorders. They are also used as anesthetics and have sound effects on the motor and sensory functions. Barbiturates are malonylurea derivatives with a variety of substituents at C-5 position showing resemblance with nitrogen and sulfur containing compounds like thiouracil which exhibited potent anticancer and antiviral activities. Recently, barbituric acid derivatives have also received great interest for applications in nanoscience. Synthesis of 5-arylidene-N,N-diethylthiobarbiturates, biological evaluation as potential α-glucosidase inhibitors and molecular modeling. In the present study, N,N-Diethylthiobarbituric acid derivatives were synthesized by refluxing of N,N-diethylthiobarbituric acid and different aromatic aldehydes in distilled water. In a typical reaction; a mixture of N,N-diethylthiobarbituric acid 0.20 g (1 mmol) and 5-bromo-2- hydroxybenzaldehyde 0.199 g (1 mmol) mixed in 10 mL distilled water and reflux for 30 minutes. After completion of the reaction, the corresponding product 1 was filtered and dried and yield calculated. It was crystallized from ethanol. The structures of synthesized compounds 1-25 were carried out by using 1H, 13C NMR, EI spectroscopy and CHN analysis used for the determination of their structures. The α-glucosidase inhibition assay was performed as given by Chapdelaine et al., with slight modifications and optimization. Our newly synthesized compounds showed a varying degree of α-glucosidase inhibition and at least four of them were found as potent inhibitors. Compounds 6, 5, 17, 11 exhibited IC50 values (Mean±SEM) of 0.0006 ± 0.0002, 18.91 ± 0.005, 19.18 ± 0.002, 36.91 ± 0.003 µM, respectively, as compared to standard acarbose (IC50, 38.25 ± 0.12 µM). Our present study has shown that compounds 6, 5, 17, 11 exhibited IC50 values of 0.0006 ± 0.0002, 18.91 ± 0.005, 19.18 ± 0.002, 36.91 ± 0.003 µM, respectively. The studies were supported by in silico data analysis.

Oxetane-containing metabolites: origin, structures, and biological activities.

Cyclobutanes containing one oxygen atom in a molecule are called oxetane-containing compounds (OCC). More than 600 different OCC are found in nature; they are produced by microorganisms, and also found in marine invertebrates and algae. The greatest number of them is found in plants belonging to the genus Taxus. Oxetanes are high-energy oxygen-containing non-aromatic heterocycles that are of great interest as new potential pharmacophores with a significant spectrum of biological activities. The biological activity of OCC that is produced by bacteria and Actinomycetes demonstrates antineoplastic, antiviral (arbovirus), and antifungal activity with confidence an angiogenesis stimulator, respiratory analeptic, and antiallergic activity dominate with confidence from 81 to 99%.

Metal chelators for the inhibition of the lymphocytic choriomeningitis virus endonuclease domain

Arenaviridae is a viral family whose members are associated with rodent-transmitted infections to humans responsible of severe diseases. The current lack of a vaccine and limited therapeutic options make the development of efficacious drugs of high priority. The cap-snatching mechanism of transcription of Arenavirus performed by the endonuclease domain of the L-protein is unique and essential, so we developed a drug design program targeting the endonuclease activity of the prototypic Lymphocytic ChorioMeningitis Virus. Since the endonuclease activity is metal ion dependent, we designed a library of compounds bearing chelating motifs (diketo acids, polyphenols, and N-hydroxyisoquinoline-1,3-diones) able to block the catalytic center through the chelation of the critical metal ions, resulting in a functional impairment. We pre-screened 59 compounds by Differential Scanning Fluorimetry. Then, we characterized the binding affinity by Microscale Thermophoresis and evaluated selected compounds in in vitro and in cellula assays. We found several potent binders and inhibitors of the endonuclease activity. This study validates the proof of concept that the endonuclease domain of Arenavirus can be used as a target for anti-arena-viral drug discovery and that both diketo acids and N-hydroxyisoquinoline-1,3-diones can be considered further as potential metal-chelating pharmacophores.

Exploration of the ESIPT process in a newly designed potential bioactive thiosemicarbazone Schiff base: Spectroscopic analysis accompanied by molecular optimization and crystallographic study

The DNA targeting nature of thiosemicarbazone based Schiff bases has provided a great platform for synthesis of its novel derivatives and their progressive exploitation as therapeutic agents. The present work embodies the synthesis of a potential bioactive pharmacophore thiosemicarbazone Schiff base derivative viz. (E)-1-(4-(diethylamino)-2-hydroxybenzylidene)-4,4-dimethyl-thiosemicarbazide (DAHTS) along with its structural characterisation by 1H NMR, FT-IR, mass spectrometry and single crystal X-ray diffraction analysis. Identification of ground and excited state geometries of the synthesized DAHTS molecule, with possibility of solvent dependent excited state intramolecular proton transfer (ESIPT) reaction have also been unveiled using electronic absorption, steady state and time resolve fluorescence spectroscopic techniques. The ESIPT process has further been validated by Density functional theory (DFT) and Time-dependent density functional theory (TD-DFT) based quantum chemical calculations. Spectral and single crystal XRD analysis indicate existence of intramolecular H-bonding between phenolic hydrogen and azomethine nitrogen in DAHTS molecule that stabilises the normal enol-imine (E) form in the ground state of DAHTS molecule. The synthesised molecule exhibits dual emission in non-polar hexane. On photoexcitation, DAHTS possibly undergoes excited state intramolecular proton transfer (ESIPT) reaction to produce keto-amine species (K) in nonpolar solvents. Frontier molecular orbital (FMO) analysis indicates that although intramolecular proton transfer reaction possibly might not occur in ground state of DAHTS but it may become feasible in the lowest singlet excited state of enol-imine form (E*) to produce its excited tautomer (K*). The lower energy difference (1.17 kcal/mol) between excited enol-imine (E*) and keto-amine (K*)form, obtained from Potential energy curve (PEC) corroborates the observed dual emission of the synthesised fluorophore. DFT and TD-DFT studies also aid in visualization of electronic charge displacement inside the molecular framework of DAHTS; which in turn suggests partial increase of Mulliken charge of azomethine nitrogen that further makes way for intramolecular proton transfer in the excited state. The amalgamated spectroscopic and theoretical research described herein, delivers enormous information about comprehensive synthetic and photophysical aspects of potential bioactive thiosemicarbazone derivatives for further utilization in medicinal chemistry research.

Organocatalytic Asymmetric Synthesis of Spiro-Bridged and Spiro-Fused Heterocyclic Compounds Containing Chromane, Indole, and Oxindole Moieties.

Following the reactivity inversion strategy, two different two-step sequences were designed and successfully applied to the asymmetric synthesis of spiro-bridged and spiro-fused heterocyclic compounds, which combined chromane, indole, and oxindole, three potential pharmacophores, in one molecule. The power of these two organocatalytic pathways is underscored by mild reaction conditions and high efficiency in the production of synthetically challenging, but biologically important heterocyclic products, which could be transformed into more biologically interesting heterocyclic structures.

A Fragment-Based Approach for the Development of G-Quadruplex Ligands: Role of the Amidoxime Moiety.

G-quadruplex (G4) nucleic acid structures have been reported to be involved in several human pathologies, including cancer, neurodegenerative disorders and infectious diseases; however, G4 targeting compounds still need implementation in terms of drug-like properties and selectivity in order to reach the clinical use. So far, G4 ligands have been mainly identified through high-throughput screening methods or design of molecules with pre-set features. Here, we describe the development of new heterocyclic ligands through a fragment-based drug discovery (FBDD) approach. The ligands were designed against the major G4 present in the long terminal repeat (LTR) promoter region of the human immunodeficiency virus-1 (HIV-1), the stabilization of which has been shown to suppress viral gene expression and replication. Our method is based on the generation of molecular fragment small libraries, screened against the target to further elaborate them into lead compounds. We screened 150 small molecules, composed by structurally and chemically different fragments, selected from commercially available and in-house compounds; synthetic elaboration yielded several G4 ligands and two final G4 binders, both embedding an amidoxime moiety; one of these two compounds showed preferential binding for the HIV-1 LTR G4. This work presents the discovery of a novel potential pharmacophore and highlights the possibility to apply a fragment-based approach to develop G4 ligands with unexpected chemical features.

Docking-based 3D-QSAR and pharmacophore studies on diarylpyrimidines as non-nucleoside inhibitors of HIV-1 reverse transcriptase.

Diarylpyrimidines (DAPYs), a type of effective HIV-1 non-nucleoside reverse transcriptase inhibitors (NNRTIs), have been considered as one of the most successful agents for treating AIDS. A number of structurally diverse DAPYs have been designed and synthesized in the past decade, and most of them exhibited potent anti-HIV-1 activities; however, the structure-activity relationships of recently reported DAPYs and their pharmacophore features that interacted with HIV-1 reverse transcriptase (RT) remain to be studied. In the present study, molecular docking studies were first performed on three novel classes of DAPYs to study their binding pattern in the HIV-1 RT. Based on the docking conformations of these DAPYs, 3D-QSAR models were constructed using CoMSIA and Topomer CoMFA methods, and pharmacophore models were also built using distance comparison technique. All selected DAPYs presented preferred U- or L-shaped conformations while being docked into the non-nucleoside inhibitor-binding pocket of the HIV-1 RT. The best CoMSIA model exhibited powerful predictivity, with satisfactory statistical parameters such as a q2 of 0.572, an r2 of 0.952, and an [Formula: see text] of 0.728. Contour maps of the best CoMSIA model were in accordance with those of the Topomer CoMFA model, giving the insight into the feature requirements of DAPYs for the anti-HIV-1 activity. Three potential pharmacophore models were constructed, and each of them was consisted of five hypothesis features. All results suggested that the aromatic ring on the left wing of DAPYs and the central pyrimidine ring contained key pharmacophore features for the anti-HIV-1 activity, and also indicated that the right wing of DAPYs had potential for further structural modification to improve activity. Eight novel DAPY molecules with potential anti-HIV-1 activities were designed on the basis of the obtained results. The findings in this study might provide important information for further design and development of novel HIV-1 NNRTIs.

Optimizing the Mizoroki–Heck reaction of cyclic allyl amines: Gram-scale synthesis of preclamol without protecting groups

Though a widely used metal-catalyzed cross-coupling process, the Mizoroki–Heck (MH) reaction can be a capricious transformation. This is particularly true for oxidation-prone alkene substrates containing ligating heteroatoms, as in the case of N-alkyl tetrahydropyridines, whose MH reactions have been underexplored due to the many side reactions that hamper the process. Since the products of tetrahydropyridine Heck reactions are direct precursors to potent pharmacophores, and therefore of commercial value, this is a significant drawback. We report here the results of our study designed to deliver an optimized, scalable MH procedure for N-alkyltetrahydropyridines and its exemplification in a gram-scale synthesis of the drug substance preclamol.

Pharmacological potential of sulfated polygalactopyranosyl-fucopyranan from the brown seaweed Sargassum wightii

A sulfated polygalactopyranosyl-fucopyranan characterized as ∙∙∙∙ → 1)-α-Fucp-(2SO3−)-(3 → 1)-α-Fucp-(2SO3−)-(4 → 1)-β-Galp-(4 → 1)-β-Galp-(4 → ∙∙∙∙ was isolated from the brown seaweed Sargassum wightii and evaluated for pharmacological properties with reference to antioxidant, anti-inflammatory, antidiabetic, and antihypertensive activities using different in vitro models. The sulfated polygalactopyranosyl-fucopyranan displayed potential di(phenyl)-(2,4,6-trinitrophenyl) iminoazanium (DPPH), 2,2′-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid (ABTS+) radical scavenging, and Fe2+ ion chelating activities (IC90 ~ 1 mg mL−1). The studied polysaccharide displayed higher anti-inflammatory selectivity towards inducive pro-inflammatory enzyme cyclooxygenase-2 (COX-2, IC90 1.13 mg mL−1) than constitutive cyclooxygenase-1 (COX-1, IC90 > 1.20 mg mL−1) resulting in greater selectivity index (IC90 COX-2/COX-1, 0.93) than synthetic non-steroidal anti-inflammatory drug aspirin (0.88) and also showed potent lipoxygenase-5 inhibition (LOX-5, IC90 1.02 mg mL−1). The studied polysaccharide displayed significantly higher (P < 0.05) antidiabetic properties compared to the antidiabetic agents acarbose and diprotein-A in terms of α-amylase (IC90 0.93 mg mL−1), α-glucosidase (IC90 1.48 mg mL−1), and dipeptidyl peptidase-4 (IC90 0.11 mg mL−1) enzyme inhibition potentials. The sulfated polygalactopyranosyl-fucopyranan also displayed potential antihypertensive activity with reference to angiotensin-converting enzyme-I inhibitory activity (IC90 0.2 mg mL−1). Extensive spectroscopic experiments in conjugation with monosaccharide compositional analysis attributed (1 → 3)-linked α-fucopyranose units in the polygalactofucan chain with C-2 sulfation and C-4 substituents as O-acetyl/O-methyl/(1 → 4)-linked β-galactopyranose. The previously undescribed sulfated polygalactopyranosyl-fucopyranan could function as a potential pharmacophore lead against inflammation, type 2 diabetics, hypertension and utilization as natural antioxidant.

Target discovery of cytotoxic withanolides from Physalis angulata var. villosa via reactivity-based screening

The reactivity-based screening (RBS) was developed for directed discovery of cytotoxic withanolides. In this study, a thiol probe, 4-chlorobenzenethiol, was used to selectively attack cytotoxic withanolides containing potential pharmacophore, 2(3)-en-1-one in ring A (AEO) and 5β,6β-epoxy in ring B (BE), from the plant extract of Physalis angulata var. villosa. The screening was performed based on the potential mechanism of 4-chlorobenzenethiol nucleophilic addition to AEO, followed by detection of adducts using liquid chromatography quadrupole-time-of-flight mass spectrometry (LC-Q-TOF-MS). Guided by RBS, eleven target withanolides, including five new compounds, physagulides R-V (10–14) and six known ones (2, 7–9, 15, 16) were discovered. All of them exhibited cytotoxicity against the both tested cell lines, especially, compounds 2, 7, 8 and 14 showed potent activities with IC50 values of 1.57–6.29 μM. The results suggested that RBS was efficient and accurate for rapid identification of cytotoxic withanolides and could guide isolation of target components from the complex medicinal plant extract.

Pharmacophoric characteristics of dengue virus NS2B/NS3pro inhibitors: a systematic review of the most promising compounds.

Dengue virus (DENV) infection can lead to a wide range of clinical manifestations, including fatal hemorrhagic complications. There is a need to find effective pharmacotherapies to treat this disease due to the lack of specific immunotherapies and antiviral drugs. That said, the DENV NS2B/NS3pro protease complex is essential in both the viral multiplication cycle and in disease pathogenesis, and is considered a promising target for new antiviral therapies. Here, we performed a systematic review to evaluate the pharmacophoric characteristics of promising compounds against NS2B/NS3pro reported in the past 10years. Online searches in the PUBMED/MEDLINE and SCOPUS databases resulted in 165 articles. Eight studies, which evaluated 3,384,268 molecules exhibiting protease inhibition activity, were included in this review. These studies evaluated anti-dengue activity in vitro and the IC50 and EC50 values were provided. Most compounds exhibited non-competitive inhibition. Cytotoxicity was evaluated in BHK-21, Vero, and LLC-MK2 cells, and the CC50 values obtained ranged from <1.0 to 780.5µM. Several groups were associated with biological activity against dengue, including nitro, catechol, halogen and ammonium quaternaries. Thus, these groups seem to be potential pharmacophores that can be further investigated to treat dengue infections.