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1.
Chem Biodivers ; : e202401238, 2024 Jul 29.
Article in English | MEDLINE | ID: mdl-39075025

ABSTRACT

The evolutionarily conserved extracellular signal-regulated kinase 2 (ERK2) is involved in regulating cellular signaling in both normal and pathological conditions. ERK2 expression is critical for human development, while hyperactivation is a major factor in tumor progression. Up to now, there have been no approved inhibitors that target ERK2, and as such, here we report on screening of a naturally occurring plant-based anticancerous compound-activity-target (NPACT) database for prospective ERK2 inhibitors. More than 1,500 phytochemicals were screened using in-silico molecular docking and molecular dynamics (MD) approaches. NPACT compounds with a docking score lower than a co-crystallized LHZ inhibitor (calc.-10.5 kcal/mol) were subjected to MD simulations. Binding energies (ΔGbinding) of inhibitor-ERK2 complexes over the MD course were estimated using an MM-GBSA approach. Based on MM-GBSA//100 ns MD simulations, the steroid zhankuic acid C (NPACT01034) demonstrated greater binding affinity against ERK2 protein than LHZ, with ΔGbinding values of -50.0 and -47.7 kcal/mol, respectively. Structural and energetical analyses throughout the MD course demonstrated stabilization of zhankuic acid C complexed with ERK2 protein. The anticipated ADMET properties of zhankuic acid C indicated minimal toxicity. Moreover, in-silico evaluation of fourteen ERK2 inhibitors in clinical trials demonstrated the higher binding affinity of zhankuic acid C towards ERK2 protein.

2.
Molecules ; 28(2)2023 Jan 09.
Article in English | MEDLINE | ID: mdl-36677732

ABSTRACT

Centaurea is a genus compromising over 250 herbaceous flowering species and is used traditionally to treat several ailments. Among the Egyptian Centaurea species, C. lipii was reported to be cytotoxic against multidrug-resistant cancer cells. In this context, we aimed to explore the metabolome of C. lipii and compare it to other members of the genus in pursuance of identifying its bioactive principles. An LC-MS/MS analysis approach synchronized with feature-based molecular networks was adopted to offer a holistic overview of the metabolome diversity of the Egyptian Centaurea species. The studied plants included C. alexandrina, C. calcitrapa, C. eryngioides, C. glomerata, C. lipii, C. pallescens, C. pumilio, and C. scoparia. Their constitutive metabolome showed diverse chemical classes such as cinnamic acids, sesquiterpene lactones, flavonoids, and lignans. Linking the recorded metabolome to the previously reported cytotoxicity identified sesquiterpene lactones as the major contributors to this activity. To confirm our findings, bioassay-guided fractionation of C. lipii was adopted and led to the isolation of the sesquiterpene lactone cynaropicrin with an IC50 of 1.817 µM against the CCRF-CEM leukemia cell line. The adopted methodology highlighted the uniqueness of the constitutive metabolome of C. lipii and determined the sesquiterpene lactones to be the responsible cytotoxic metabolites.


Subject(s)
Antineoplastic Agents , Centaurea , Sesquiterpenes , Plant Extracts/chemistry , Chromatography, Liquid , Drug Resistance, Multiple , Egypt , Drug Resistance, Neoplasm , Tandem Mass Spectrometry , Centaurea/chemistry , Phytochemicals/pharmacology , Sesquiterpenes/chemistry , Lactones/chemistry
3.
Molecules ; 28(15)2023 Jul 28.
Article in English | MEDLINE | ID: mdl-37570684

ABSTRACT

BRD4 (bromodomain-containing protein 4) is an epigenetic reader that realizes histone proteins and promotes the transcription of genes linked to cancer progression and non-cancer diseases such as acute heart failure and severe inflammation. The highly conserved N-terminal bromodomain (BD1) recognizes acylated lysine residues to organize the expression of genes. As such, BD1 is essential for disrupting BRD4 interactions and is a promising target for cancer treatment. To identify new BD1 inhibitors, a SuperDRUG2 database that contains more than 4600 pharmaceutical compounds was screened using in silico techniques. The efficiency of the AutoDock Vina1.1.2 software to anticipate inhibitor-BRD4-BD1 binding poses was first evaluated based on the co-crystallized R6S ligand in complex with BRD4-BD1. From database screening, the most promising BRD4-BD1 inhibitors were subsequently submitted to molecular dynamics (MD) simulations integrated with an MM-GBSA approach. MM-GBSA computations indicated promising BD1 binding with a benzonaphthyridine derivative, pyronaridine (SD003509), with an energy prediction (ΔGbinding) of -42.7 kcal/mol in comparison with -41.5 kcal/mol for a positive control inhibitor (R6S). Pharmacokinetic properties predicted oral bioavailability for both ligands, while post-dynamic analyses of the BRD4-BD1 binding pocket demonstrated greater stability for pyronaridine. These results confirm that in silico studies can provide insight into novel protein-ligand regulators, specifically that pyronaridine is a potential cancer drug candidate.


Subject(s)
Molecular Dynamics Simulation , Nuclear Proteins , Molecular Docking Simulation , Nuclear Proteins/metabolism , Bromodomain Containing Proteins , Transcription Factors/metabolism , Ligands , Cell Cycle Proteins/metabolism
4.
Phytopathology ; 112(4): 862-871, 2022 Apr.
Article in English | MEDLINE | ID: mdl-34622696

ABSTRACT

With the progressive loss of fungicide efficacy against Phakopsora pachyrhizi, the causal agent of Asian soybean rust (ASR), alternative methods to protect soybean crops are needed. Resistance induction is a low impact alternative and/or supplement to fungicide applications that fortifies innate plant defenses against pathogens. Here, we show that a microbial fermentation product (MFP) induces plant defenses in soybean, and transcriptional induction is enhanced with the introduction of ASR. MFP-treated plants exhibited 1,011 and 1,877 differentially expressed genes (DEGs) 12 and 60 h after treatment, respectively, compared with water controls. MFP plants exposed to the pathogen 48 h after application and sampled 12 h later (for a total of 60 h) had 2,401 DEGs compared with control. The plant defense genes PR1, PR2, IPER, PAL, and CHS were induced with MFP application, and induction was enhanced with ASR. Enriched pathways associated with pathogen defense included plant-pathogen interactions, MAPK signaling pathways, phenylpropanoid biosynthesis, glutathione metabolism, flavonoid metabolism, and isoflavonoid metabolism. In field conditions, elevated antioxidant peroxidase activities and phenolic accumulation were measured with MFP treatment; however, improved ASR control or enhanced crop yield were not observed. MFP elicitation differences between field and laboratory grown plants necessitates further testing to identify best practices for effective disease management with MFP-treated soybean.


Subject(s)
Glycine max , Phakopsora pachyrhizi , Fermentation , Gene Expression Regulation, Plant , Plant Diseases/genetics , Glycine max/genetics
5.
Molecules ; 27(18)2022 Sep 08.
Article in English | MEDLINE | ID: mdl-36144570

ABSTRACT

Natural products and chemical analogues are widely used in drug discovery, notably in cancer and infectious disease pharmacotherapy. Sarcophyton convolutum (Alcyoniidae) a Red Sea-derived soft coral has been shown to be a rich source of macrocyclic diterpenes and cyclized derivatives. Two previously undescribed polyoxygenated cembrane-type diterpenoids, sarcoconvolutums F (1) and G (2), as well as four identified analogues (3-6) together with a furan derivate (7) were isolated from a solvent extract. Compounds were identified by spectroscopic techniques, including NMR, HREIMS, and CD, together with close spectral comparisons of previously published data. Sarcoconvolutum F (1) contains a rare 1-peroxid-15-hydroxy-10-ene functionality. Isolated metabolites (1-7) were screened against lung adenocarcinoma (A549), cervical cancer (HeLa) and oral cavity carcinoma (HSC-2) lines. Compound 4 exhibited an IC50 56 µM and 55 µM against A549 and HSC-2 cells, respectively.


Subject(s)
Anthozoa , Biological Products , Diterpenes , Animals , Anthozoa/chemistry , Biological Products/pharmacology , Diterpenes/chemistry , Diterpenes/pharmacology , Furans , Indian Ocean , Molecular Structure , Solvents
6.
Molecules ; 27(10)2022 May 12.
Article in English | MEDLINE | ID: mdl-35630581

ABSTRACT

The P-glycoprotein (P-gp/ABCB1) is responsible for a xenobiotic efflux pump that shackles intracellular drug accumulation. Additionally, it is included in the dud of considerable antiviral and anticancer chemotherapies because of the multidrug resistance (MDR) phenomenon. In the search for prospective anticancer drugs that inhibit the ABCB1 transporter, the Natural Product Activity and Species Source (NPASS) database, containing >35,000 molecules, was explored for identifying ABCB1 inhibitors. The performance of AutoDock4.2.6 software to anticipate ABCB1 docking score and pose was first assessed according to available experimental data. The docking scores of the NPASS molecules were predicted against the ABCB1 transporter. Molecular dynamics (MD) simulations were conducted for molecules with docking scores lower than taxol, a reference inhibitor, pursued by molecular mechanics-generalized Born surface area (MM-GBSA) binding energy estimations. On the basis of MM-GBSA calculations, five compounds revealed promising binding affinities as ABCB1 inhibitors with ΔGbinding < −105.0 kcal/mol. The binding affinity and stability of the identified inhibitors were compared to the chemotherapeutic agent. Structural and energetical analyses unveiled great steadiness of the investigated inhibitors within the ABCB1 active site throughout 100 ns MD simulations. Conclusively, these findings point out that NPC104372, NPC475164, NPC2313, NPC197736, and NPC477344 hold guarantees as potential ABCB1 drug candidates and warrant further in vitro/in vivo tests.


Subject(s)
Antineoplastic Agents , Biological Products , Antineoplastic Agents/pharmacology , ATP Binding Cassette Transporter, Subfamily B/metabolism , Biological Products/pharmacology , Drug Discovery , Prospective Studies
7.
J Integr Plant Biol ; 64(6): 1135-1139, 2022 Jun.
Article in English | MEDLINE | ID: mdl-35377511

ABSTRACT

Premature plant senescence induced by abiotic stresses is a major cause of agricultural losses worldwide. Tools for suppressing stress-induced plant senescence are limited. Here, we report that diacetyl, a natural compound emitted by the plant-beneficial bacterium Bacillus amyloliquefaciens, suppresses abscisic acid -mediated foliar senescence in Arabidopsis thaliana under various abiotic stress conditions. Our results establish diacetyl as an effective protector against stress-induced plant senescence and reveal a molecular mechanism for bacteria-enhanced plant stress resistance.


Subject(s)
Arabidopsis Proteins , Arabidopsis , Abscisic Acid/pharmacology , Arabidopsis/metabolism , Arabidopsis Proteins/metabolism , Bacteria , Diacetyl/pharmacology , Gene Expression Regulation, Plant , Plant Leaves/metabolism , Plants/metabolism , Stress, Physiological
8.
Mar Drugs ; 19(9)2021 Sep 13.
Article in English | MEDLINE | ID: mdl-34564181

ABSTRACT

The soft coral genus Sarcophyton contains the enzymatic machinery to synthesize a multitude of cembrene-type diterpenes. Herein, highly oxygenated cembrenoids, sarcoconvolutum A-E (1-5) were purified and characterized from an ethyl acetate extract of the red sea soft coral, Sarcophyton convolutum. Compounds were assemblies according to spectroscopic methods including FTIR, 1D- and 2D-NMR as well as HRMS. Metabolite cytotoxicity was tested against lung adenocarcinoma, cervical cancer, and oral-cavity carcinoma (A549, HeLa and HSC-2, respectively). The most cytotoxic compound, (4) was observed to be active against cell lines A549 and HSC-2 with IC50 values of 49.70 and 53.17 µM, respectively.


Subject(s)
Anthozoa , Antineoplastic Agents/pharmacology , Diterpenes/pharmacology , Animals , Aquatic Organisms , Cell Line, Tumor , Drug Screening Assays, Antitumor , Indian Ocean , Inhibitory Concentration 50 , Magnetic Resonance Spectroscopy , Structure-Activity Relationship
9.
Mar Drugs ; 19(7)2021 Jul 13.
Article in English | MEDLINE | ID: mdl-34356816

ABSTRACT

The coronavirus pandemic has affected more than 150 million people, while over 3.25 million people have died from the coronavirus disease 2019 (COVID-19). As there are no established therapies for COVID-19 treatment, drugs that inhibit viral replication are a promising target; specifically, the main protease (Mpro) that process CoV-encoded polyproteins serves as an Achilles heel for assembly of replication-transcription machinery as well as down-stream viral replication. In the search for potential antiviral drugs that target Mpro, a series of cembranoid diterpenes from the biologically active soft-coral genus Sarcophyton have been examined as SARS-CoV-2 Mpro inhibitors. Over 360 metabolites from the genus were screened using molecular docking calculations. Promising diterpenes were further characterized by molecular dynamics (MD) simulations based on molecular mechanics-generalized Born surface area (MM-GBSA) binding energy calculations. According to in silico calculations, five cembranoid diterpenes manifested adequate binding affinities as Mpro inhibitors with ΔGbinding < -33.0 kcal/mol. Binding energy and structural analyses of the most potent Sarcophyton inhibitor, bislatumlide A (340), was compared to darunavir, an HIV protease inhibitor that has been recently subjected to clinical-trial as an anti-COVID-19 drug. In silico analysis indicates that 340 has a higher binding affinity against Mpro than darunavir with ΔGbinding values of -43.8 and -34.8 kcal/mol, respectively throughout 100 ns MD simulations. Drug-likeness calculations revealed robust bioavailability and protein-protein interactions were identified for 340; biochemical signaling genes included ACE, MAPK14 and ESR1 as identified based on a STRING database. Pathway enrichment analysis combined with reactome mining revealed that 340 has the capability to re-modulate the p38 MAPK pathway hijacked by SARS-CoV-2 and antagonize injurious effects. These findings justify further in vivo and in vitro testing of 340 as an antiviral agent against SARS-CoV-2.


Subject(s)
Anthozoa/chemistry , COVID-19 Drug Treatment , Coronavirus 3C Proteases/antagonists & inhibitors , Coronavirus Protease Inhibitors/pharmacology , Diterpenes/pharmacology , SARS-CoV-2/drug effects , Animals , COVID-19/virology , Coronavirus 3C Proteases/metabolism , Coronavirus Protease Inhibitors/chemistry , Coronavirus Protease Inhibitors/isolation & purification , Diterpenes/chemistry , Diterpenes/isolation & purification , Humans , Molecular Docking Simulation , Molecular Dynamics Simulation , Molecular Structure , SARS-CoV-2/enzymology , SARS-CoV-2/pathogenicity , Structure-Activity Relationship
10.
Molecules ; 26(7)2021 Apr 03.
Article in English | MEDLINE | ID: mdl-33916714

ABSTRACT

Centaurothamnus maximus (family Asteraceae), is a leafy shrub indigenous to the southwestern Arabian Peninsula. With a paucity of phytochemical data on this species, we set out to chemically characterize the plant. From the aerial parts, two newly identified guaianolides were isolated: 3ß-hydroxy-4α(acetoxy)-4ß(hydroxymethyl)-8α-(4-hydroxy methacrylate)-1αH,5αH, 6αH-gual-10(14),11(13)-dien-6,12-olide (1) and 15-descarboxy picrolide A (2). Seven previously reported compounds were also isolated: 3ß, 4α, 8α-trihydroxy-4-(hydroxymethyl)-lαH, 5αH, 6ßH, 7αH-guai-10(14),11(13)-dien-6,12-olide (3), chlorohyssopifolin B (4), cynaropikrin (5), hydroxyjanerin (6), chlorojanerin (7), isorhamnetin (8), and quercetagetin-3,6-dimethyl ether-4'-O-ß-d-pyranoglucoside (9). Chemical structures were elucidated using spectroscopic techniques, including High Resolution Fast Atom Bombardment Mass Spectrometry (HR-FAB-MS), 1D NMR; 1H, 13C NMR, Distortionless Enhancement by Polarization Transfer (DEPT), and 2D NMR (1H-1H COSY, HMQC, HMBC) analyses. In addition, a biosynthetic pathway for compounds 1-9 is proposed. The chemotaxonomic significance of the reported sesquiterpenoids and flavonoids considering reports from other Centaurea species is examined.


Subject(s)
Asteraceae/chemistry , Lactones/isolation & purification , Sesquiterpenes, Guaiane/isolation & purification , Biosynthetic Pathways , Carbon-13 Magnetic Resonance Spectroscopy , Flavones/chemistry , Flavones/isolation & purification , Lactones/chemistry , Molecular Conformation , Proton Magnetic Resonance Spectroscopy , Sesquiterpenes, Guaiane/chemistry
11.
Molecules ; 26(7)2021 Apr 05.
Article in English | MEDLINE | ID: mdl-33916461

ABSTRACT

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is the causative agent for the COVID-19 pandemic, which generated more than 1.82 million deaths in 2020 alone, in addition to 83.8 million infections. Currently, there is no antiviral medication to treat COVID-19. In the search for drug leads, marine-derived metabolites are reported here as prospective SARS-CoV-2 inhibitors. Two hundred and twenty-seven terpene natural products isolated from the biodiverse Red-Sea ecosystem were screened for inhibitor activity against the SARS-CoV-2 main protease (Mpro) using molecular docking and molecular dynamics (MD) simulations combined with molecular mechanics/generalized Born surface area binding energy calculations. On the basis of in silico analyses, six terpenes demonstrated high potency as Mpro inhibitors with ΔGbinding ≤ -40.0 kcal/mol. The stability and binding affinity of the most potent metabolite, erylosides B, were compared to the human immunodeficiency virus protease inhibitor, lopinavir. Erylosides B showed greater binding affinity towards SARS-CoV-2 Mpro than lopinavir over 100 ns with ΔGbinding values of -51.9 vs. -33.6 kcal/mol, respectively. Protein-protein interactions indicate that erylosides B biochemical signaling shares gene components that mediate severe acute respiratory syndrome diseases, including the cytokine- and immune-signaling components BCL2L1, IL2, and PRKC. Pathway enrichment analysis and Boolean network modeling were performed towards a deep dissection and mining of the erylosides B target-function interactions. The current study identifies erylosides B as a promising anti-COVID-19 drug lead that warrants further in vitro and in vivo testing.


Subject(s)
Invertebrates/chemistry , SARS-CoV-2/metabolism , Terpenes/chemistry , Viral Matrix Proteins/antagonists & inhibitors , Animals , Binding Sites , COVID-19/virology , Humans , Hydrogen Bonding , Invertebrates/metabolism , Lopinavir/chemistry , Lopinavir/metabolism , Molecular Docking Simulation , Molecular Dynamics Simulation , Protease Inhibitors/chemistry , Protease Inhibitors/isolation & purification , Protease Inhibitors/therapeutic use , Protein Binding , SARS-CoV-2/isolation & purification , Terpenes/isolation & purification , Terpenes/metabolism , Terpenes/therapeutic use , Thermodynamics , Viral Matrix Proteins/metabolism , COVID-19 Drug Treatment
12.
Crit Rev Biotechnol ; 40(1): 64-82, 2020 Feb.
Article in English | MEDLINE | ID: mdl-31663377

ABSTRACT

Structurally diverse natural products are valued for their targeted biological activity. The challenge of working with such metabolites is their low natural abundance and complex structure, often with multiple stereocenters, precludes large-scale or unsophisticated chemical synthesis. Since select plants contain the enzymatic machinery necessary to produce specialized compounds, tissue cultures can be used to achieve key transformations for large-scale chemical and/or pharmaceutical applications. In this context, plant tissue-culture bio-transformations have demonstrated great promise in the preparation of pharmaceutical products. This review describes the capacity of cultured plant cells to transform terpenoid natural products and the specific application of such transformations over the past three decades (1988-2019).


Subject(s)
Plants/metabolism , Terpenes/metabolism , Biotransformation , Cell Culture Techniques , Plant Structures/metabolism
13.
Molecules ; 23(9)2018 Sep 01.
Article in English | MEDLINE | ID: mdl-30200407

ABSTRACT

Euphorbia species are rich in diterpenes. A solvent extraction of Euphorbia sanctae-catharinae, a species indigenous to the Southern Sinai of Egypt, afforded several premyrsinane diterpenoids (1⁻4) as well as previously reported metabolites (5⁻13) that included three flavonoids. Isolated compounds were chemically characterized by spectroscopic analysis. Identified compounds were bioassayed for anti-proliferative activity in vitro against colon (Caco-2) and lung (A549) tumor cell lines. Compound 9 exhibited robust anti-proliferative activity against A549 cells (IC50 = 3.3 µM). Absolute configurations for 8 versus 9 were determined by experimental and TDDFT-calculated electronic circular dichorism (ECD) spectra.


Subject(s)
Diterpenes/pharmacology , Euphorbia/chemistry , A549 Cells , Caco-2 Cells , Carbon-13 Magnetic Resonance Spectroscopy , Cell Proliferation/drug effects , Circular Dichroism , Diterpenes/chemistry , Humans , Inhibitory Concentration 50 , Proton Magnetic Resonance Spectroscopy
14.
J Proteome Res ; 16(7): 2579-2586, 2017 07 07.
Article in English | MEDLINE | ID: mdl-28541047

ABSTRACT

Growth inhibition of the pathogen Staphylococcus aureus with currently available antibiotics is problematic in part due to bacterial biofilm protection. Although recently characterized natural products, including 3',4',5-trihydroxy-6,7-dimethoxy-flavone [1], 3',4',5,6,7-pentahydroxy-flavone [2], and 5-hydroxy-4',7-dimethoxy-flavone [3], exhibit both antibiotic and biofilm inhibitory activities, the mode of action of such hydroxylated flavonoids with respect to S. aureus inhibition is yet to be characterized. Enzymatic digestion and high-resolution MS analysis of differentially expressed proteins from S. aureus with and without exposure to antibiotic flavonoids (1-3) allowed for the characterization of global protein alterations induced by metabolite treatment. A total of 56, 92, and 110 proteins were differentially expressed with bacterial exposure to 1, 2, or 3, respectively. The connectivity of the identified proteins was characterized using a search tool for the retrieval of interacting genes/proteins (STRING) with multitargeted S. aureus inhibition of energy metabolism and biosynthesis by the assayed flavonoids. Identifying the mode of action of natural products as antibacterial agents is expected to provide insight into the potential use of flavonoids alone or in combination with known therapeutic agents to effectively control S. aureus infection.


Subject(s)
Anti-Bacterial Agents/pharmacology , Bacterial Proteins/genetics , Biofilms/drug effects , Flavonoids/pharmacology , Gene Expression Regulation, Bacterial , Staphylococcus aureus/drug effects , Apigenin/pharmacology , Bacterial Proteins/isolation & purification , Bacterial Proteins/metabolism , Biofilms/growth & development , Chromatography, Liquid , Energy Metabolism/drug effects , Energy Metabolism/genetics , Flavones/pharmacology , Luteolin/pharmacology , Molecular Sequence Annotation , Proteomics/methods , Staphylococcus aureus/genetics , Staphylococcus aureus/growth & development , Staphylococcus aureus/metabolism , Tandem Mass Spectrometry
15.
Bioorg Med Chem Lett ; 27(16): 3825-3828, 2017 08 15.
Article in English | MEDLINE | ID: mdl-28676273

ABSTRACT

While select eudesmane sesquiterpenes exhibit anti-neoplastic activity, tumor-inhibition for costic-acids has not been established. Here biological activity of 3-oxo-γ-costic acid (1), previously isolated from Chiliadenus montanus, as well as new sesquiterpenes (2-5) and the known derivative, 3-oxoeudesma-1,4,11(13)-trien-7-1061αH-l2-oic acid (6), all produced from 1 by the fungus Athelia rolfsii, are reported. Structures were elucidated using MS and NMR spectroscopy with activity-screening utilizing human colon- and lung-tumor lines, Caco-2 and A549 respectively. Compound 1 exhibited anti-proliferative activity against Caco-2 (IC50 39µM) and 2 was active against A549 (IC50 74µM) suggesting therapeutic potential for the original substrate and a bio-transformed product.


Subject(s)
Antineoplastic Agents/pharmacology , Basidiomycota/chemistry , Sesquiterpenes, Eudesmane/pharmacology , Antineoplastic Agents/chemistry , Antineoplastic Agents/isolation & purification , Cell Line, Tumor , Cell Proliferation/drug effects , Dose-Response Relationship, Drug , Drug Screening Assays, Antitumor , Humans , Molecular Structure , Sesquiterpenes, Eudesmane/chemistry , Sesquiterpenes, Eudesmane/isolation & purification , Structure-Activity Relationship
16.
Mar Drugs ; 15(6)2017 Jun 21.
Article in English | MEDLINE | ID: mdl-28635645

ABSTRACT

Three new cembrene diterpenoids, sarcoehrenbergilid A-C (1-3), along with four known diterpenoids, sarcophine (4), (+)-7α,8ß-dihydroxydeepoxysarcophine (5), sinulolide A (6), and sinulolide B (7), and one steroid, sardisterol (8), were isolated and characterized from a solvent extract of the Red Sea soft coral Sarcophyton ehrenbergi. Chemical structures were elucidated by NMR and MS analyses with absolute stereochemistry determined by X-ray analysis. Since these isolated cembrene diterpenes contained 10 or more carbons in a large flexible ring, conformer stabilities were examined based on density functional theory calculations. Anti-proliferative activities for 1-8 were evaluated against three human tumor cell lines of different origins including the: lung (A549), colon (Caco-2), and liver (HepG2). Sardisterol (8) was the most potent of the metabolites isolated with an IC50 of 27.3 µM against the A549 cell line. Since an elevated human-cancer occurrence is associated with an aberrant receptor function for the epidermal growth factor receptor (EGFR), molecular docking studies were used to examine preferential metabolite interactions/binding and probe the mode-of-action for metabolite-anti tumor activity.


Subject(s)
Anthozoa/chemistry , Cell Proliferation/drug effects , Diterpenes/chemistry , Diterpenes/pharmacology , Ether/chemistry , 4-Butyrolactone/analogs & derivatives , 4-Butyrolactone/pharmacology , A549 Cells , Animals , Antineoplastic Agents/chemistry , Antineoplastic Agents/pharmacology , Caco-2 Cells , Cell Line, Tumor , Hep G2 Cells , Humans , Indian Ocean , Magnetic Resonance Spectroscopy/methods , Molecular Docking Simulation
17.
J Asian Nat Prod Res ; 19(11): 1093-1101, 2017 Nov.
Article in English | MEDLINE | ID: mdl-28361549

ABSTRACT

Two new sesquiterpene lactones 3R, 8R-dihydroxygermacr-4(15),9(10)-dien-6S,7S,11RH,12,6-olide (1) and 1R, 8S-dihydroxy-11R,13-dihydrobalchanin(2), together with two known compounds 11-epiartapshin (3) and 3'-hydroxygenkwanin (4), were isolated from Artemisia sieberi. Their structures were elucidated by 1D, 2D NMR, MS, and X-ray diffraction. Compound 4 inhibited Gram-positive bacteria Bacillus subtilis and Staphylococcus aureus with Minimal inhibitory concentration values of 50 and 25 µg/disk, respectively. All the isolated compounds exhibited moderate antifungal activities.


Subject(s)
Anti-Bacterial Agents/isolation & purification , Anti-Bacterial Agents/pharmacology , Artemisia/chemistry , Asteraceae/chemistry , Lactones/isolation & purification , Lactones/pharmacology , Sesquiterpenes/isolation & purification , Sesquiterpenes/pharmacology , Anti-Bacterial Agents/chemistry , Bacillus subtilis/drug effects , Lactones/chemistry , Microbial Sensitivity Tests , Molecular Structure , Plant Extracts/chemistry , Sesquiterpenes/chemistry , Staphylococcus aureus/drug effects , Stereoisomerism
18.
Int J Mol Sci ; 18(12)2017 Dec 11.
Article in English | MEDLINE | ID: mdl-29232909

ABSTRACT

Water retaining agent (WRA) is widely used for soil erosion control and agricultural water saving. Here, we evaluated the effects of the combination of beneficial soil bacterium Bacillus amyloliquefaciens strain GB03 and WRA (the compound is super absorbent hydrogels) on drought tolerance of perennial ryegrass (Lolium perenne L.). Seedlings were subjected to natural drought for maximum 20 days by stopping watering and then rewatered for seven days. Plant survival rate, biomass, photosynthesis, water status and leaf cell membrane integrity were measured. The results showed that under severe drought stress (20-day natural drought), compared to control, GB03, WRA and GB03+WRA all significantly improved shoot fresh weight, dry weight, relative water content (RWC) and chlorophyll content and decreased leaf relative electric conductivity (REC) and leaf malondialdehyde (MDA) content; GB03+WRA significantly enhanced chlorophyll content compared to control and other two treatments. Seven days after rewatering, GB03, WRA and GB03+WRA all significantly enhanced plant survival rate, biomass, RWC and maintained chlorophyll content compared to control; GB03+WRA significantly enhanced plant survival rate, biomass and chlorophyll content compared to control and other two treatments. The results established that GB03 together with water retaining agent promotes ryegrass growth under drought conditions by improving survival rate and maintaining chlorophyll content.


Subject(s)
Bacillus amyloliquefaciens/physiology , Chlorophyll/metabolism , Hydrogels/pharmacology , Lolium/growth & development , Soil Microbiology , Biomass , Droughts , Lolium/metabolism , Malondialdehyde/metabolism , Photosynthesis , Plant Leaves/metabolism , Stress, Physiological/drug effects , Water
19.
Rapid Commun Mass Spectrom ; 30(18): 2033-42, 2016 09 30.
Article in English | MEDLINE | ID: mdl-27469085

ABSTRACT

RATIONALE: While natural products isolated from medicinal plants can serve as a rich source of biologically active metabolites, mixtures of structurally related compounds of a polar nature are often difficult to chemically resolve by traditional separation techniques. Chemical derivatization to reduce metabolite polarity combined with liquid chromatography (LC) is the strategy presented here to resolve a mixture of structurally related natural product glycosides solvent extracted from the medicinal herb Teucrium polium for mass spectrometric characterization. METHODS: The partially purified plant extract was subjected to chemical derivatization and electrospray ionization mass spectrometry (ESI-MS) fragmentation pattern analysis allowed for structural characterization of iridoid and secoiridoid glycosides. Selected ions were subjected to tandem mass spectrometric (MS/MS) analysis with a relatively higher-energy collision dissociation to assist in structural elucidation. RESULTS: Permethylation replaced all protons from free hydroxyl and amino groups with methyls and resulted in increases in both hydrophobicity, for facilitated chromatographic separation, and proton affinity, for enhanced chemical ionization. Protonated and/or sodiated adducts were observed for the six compounds detected in positive-ion mode ESI-MS with a mass accuracy of less than 2 ppm. CONCLUSIONS: Permethylation combined with LC/MS analysis is shown here to be an effective chemical practice for separating and characterizing iridoid glucosinolates and is expected to be well suited for the chemical characterization of other polar natural-product mixtures of closely related compounds. Copyright © 2016 John Wiley & Sons, Ltd.


Subject(s)
Iridoid Glycosides/analysis , Iridoid Glycosides/chemistry , Plant Extracts/chemistry , Spectrometry, Mass, Electrospray Ionization/methods , Chromatography, Liquid/methods , Iridoid Glycosides/isolation & purification , Methylation , Teucrium/chemistry
20.
Planta Med ; 82(1-2): 138-46, 2016 Jan.
Article in English | MEDLINE | ID: mdl-26441064

ABSTRACT

Wild artichoke (Cynara cornigera), a thistle-like perennial belonging to the Asteraceae family, is native to the Mediterranean region, northwestern Africa, and the Canary Islands. While the pleasant, albeit bitter, taste of the leaves and flowers is attributed to the sesquiterpene lactones cynaropicrin and cynarin, a comprehensive phytochemical investigation still needs to be reported. In this study seven sesquiterpene lactones were isolated from an aqueous methanol plant extract, including a new halogenated metabolite (1), the naturally isolated compound sibthorpine (2), and five metabolites isolated for the first time from C. cornigera. Structures were established by spectroscopic methods, including HREIMS, (1 )H, (13 )C, DEPT, (1 )H-(1 )H COSY, HMQC, and HMBC-NMR experiments as well as by X-ray analysis. The isolated bioactive nutrients were analyzed for their antioxidant and metal chelating activity. Compound 1 exhibited a potent metal chelating activity as well as a high antioxidant capacity. Moreover, select compounds were effective as acetyl cholinesterase inhibitors presenting the possibility for such compounds to be examined for anti-neurodegenerative activity. A computational pharmacophore elucidation and docking study was performed to estimate the pharmacophoric features and binding conformation of isolated compounds in the acetyl cholinesterase active site.


Subject(s)
Cholinesterase Inhibitors/chemistry , Cynara/chemistry , Lactones/chemistry , Plant Extracts/chemistry , Sesquiterpenes/chemistry , Africa , Antioxidants/chemistry , Chelating Agents/chemistry , Cholinesterase Inhibitors/isolation & purification , Crystallography, X-Ray , Free Radical Scavengers/chemistry , Free Radical Scavengers/isolation & purification , Lactones/isolation & purification , Molecular Structure , Sesquiterpenes/isolation & purification
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