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Natural Products Chemistry Breaking News
A recompilation of news and links about natural products, organic chemistry and science more generally ...
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Plant Seed Species Identification from Chemical Fingerprints: A High-Throughput Application of Direct Analysis in Real Time Mass Spectrometry

Plant Seed Species Identification from Chemical Fingerprints: A High-Throughput Application of Direct Analysis in Real Time Mass Spectrometry | Natural Products Chemistry Breaking News | Scoop.it

Plant species identification based on the morphological features of plant parts is a well-established science in botany. However, species identification from seeds has largely been unexplored, despite the fact that the seeds contain all of the genetic information that distinguishes one plant from another. Using seeds of genus Datura plants, we show here that the mass spectrum-derived chemical fingerprints for seeds of the same species are similar. On the other hand, seeds from different species within the same genus display distinct chemical signatures, even though they may contain similar characteristic biomarkers. The intraspecies chemical signature similarities on the one hand, and interspecies fingerprint differences on the other, can be processed by multivariate statistical analysis methods to enable rapid species-level identification and differentiation. The chemical fingerprints can be acquired rapidly and in a high-throughput manner by direct analysis in real time mass spectrometry (DART-MS) analysis of the seeds in their native form, without use of a solvent extract. Importantly, knowledge of the identity of the detected molecules is not required for species level identification. However, confirmation of the presence within the seeds of various characteristic tropane and other alkaloids, including atropine, scopolamine, scopoline, tropine, tropinone, and tyramine, was accomplished by comparison of the in-source collision-induced dissociation (CID) fragmentation patterns of authentic standards, to the fragmentation patterns observed in the seeds when analyzed under similar in-source CID conditions. The advantages, applications, and implications of the chemometric processing of DART-MS derived seed chemical signatures for species level identification and differentiation are discussed.


Anal. Chem., Article ASAP
DOI: 10.1021/acs.analchem.5b01611




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BasementBiotech

BasementBiotech | Natural Products Chemistry Breaking News | Scoop.it
Protocols & Experiments for the Citizen Scientist
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Cool stuff & persons there ! Check it out

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A twist of nature – the significance of atropisomers in biological systems

A twist of nature – the significance of atropisomers in biological systems | Natural Products Chemistry Breaking News | Scoop.it


Recently identified natural atropisomeric compounds with potential medicinal applications are presented. The ability of natural receptors to possess differential binding between atropisomers is an important factor when considering active and inactive atropisomeric drugs, and has required the development of new techniques for atropselective synthesis of desired targets. Advances in this field therefore have significant relevance to modern pharmaceutical and medicinal chemistry. The atropisomeric natural products discussed include hibarimicinone, flavomannins, talaromannins, viriditoxin, rugulotrosin A, abyssomicin C, marinopyrroles, dixiamycins, streptorubin B, ustiloxins A–F, haouamine A, bisnicalaterines, and tedarene B, all of which show significant potential as leads in antibiotic, antiviral and anticancer studies. The importance for the development of common practices regarding atropisomer recognition and classification is also emphasized.


Nat. Prod. Rep., 2015, Advance Article


DOI: 10.1039/C4NP00121D


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The atropisomeric natural products discussed include talaromannins, hibarimicinone, viriditoxin, flavomannins, rugulotrosin A, abyssomicin C, dixiamycins, marinopyrroles, ustiloxins A–F, streptorubin B, bisnicalaterines, haouamine A, and tedarene B, all of which show significant potential as leads in antibiotic, anticancer and antiviral studies. 

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Pinensins: The First Antifungal Lantibiotics - Mohr

Pinensins: The First Antifungal Lantibiotics - Mohr | Natural Products Chemistry Breaking News | Scoop.it

Lantibiotics (lanthionine-containing antibiotics) from Gram-positive bacteria typically exhibit activity against Gram-positive bacteria. The activity and structure of pinensin A (1) and B (2), lantibiotics isolated from a native Gram-negative producer Chitinophaga pinensis are described. Surprisingly, the pinensins were found to be highly active against many filamentous fungi and yeasts but show only weak antibacterial activity. To the best of our knowledge, lantibiotic fungicides have not been described before. An in-depth bioinformatic analysis of the biosynthetic gene cluster established the ribosomal origin of these compounds and identified candidate genes encoding all of the enzymes required for post-translational modification. Additional encoded functions enabled us to build up a hypothesis for the biosynthesis, export, sensing, and import of this intriguing lantibiotic.


  1. Dr. Kathrin I. Mohr1,5,†, 
  2. Dr. Carsten Volz2,5,†, 
  3. Dr. Rolf Jansen1,5, 
  4. Dr. Victor Wray3,
  5. Dr. Judith Hoffmann2,5, 
  6. Dipl.-Ing. Steffen Bernecker1,5, 
  7. Priv.-Doz. Dr. Joachim Wink4,5, 
  8. Dr. Klaus Gerth4, 
  9. Prof. Dr. Marc Stadler1,5 and
  10. Prof. Dr. Rolf Müller2,5,*

Article first published online: 24 JUL 2015

DOI: 10.1002/anie.201500927


Angewandte Chemie International Edition


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Mass Spectrometric and Spectrophotometric Analyses Reveal an Alternative Structure and a New Formation Mechanism for Melanin

Mass Spectrometric and Spectrophotometric Analyses Reveal an Alternative Structure and a New Formation Mechanism for Melanin | Natural Products Chemistry Breaking News | Scoop.it

In this study, we investigated the formation mechanism and chemical structure of melanin that results from the self-assembly of l-3,4-dihydroxyphenylalanine (l-DOPA). Using a combination of “top-down” and “bottom-up” approaches, and on the basis of state-of-the-art electrospray ionization mass spectrometry (ESI-MS) results, we propose a new formation mechanism and an alternative structure for melanin. Specifically, our study of the self-aggregation of l-DOPA based on l-DOPA clusters revealed that melanin is comprised partially of noncovalent supramolecular aggregate that is formed by self-aggregation of l-DOPA and with the individual monomers linked together by a combination of hydrogen bonds, π–π stacking, and ionic bonds. Furthermore, our study showed that unmodified l-DOPA may be part of the building block for melanin in addition to the previously proposed indole derivative based on l-DOPA cyclization. A similar self-aggregation phenomenon was also observed in other structurally related catecholamines, for example, adrenaline.


Anal. Chem., Article ASAP
DOI: 10.1021/acs.analchem.5b01837


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A new NMR approach for structure determination of thermally unstable biflavanones and application to phytochemicals from Garcinia buchananii - Stark

A new NMR approach for structure determination of thermally unstable biflavanones and application to phytochemicals from Garcinia buchananii - Stark | Natural Products Chemistry Breaking News | Scoop.it
Timo D. Stark1,*, Sofie Lösch1, Mathias Salger1, Onesmo B. Balemba2, Junichiro Wakamatsu1, Oliver Frank1 andThomas Hofmann1
Article first published online: 20 JUL 2015
DOI: 10.1002/mrc.4269

Previous activity-guided phytochemical studies on Garcinia buchananii stem bark, which is traditionally used in Africa to treat various gastrointestinal and metabolic illnesses, revealed xanthones, polyisoprenylated benzophenones, flavanone-C-glycosides, biflavonoids, and/or biflavanones as bioactive key molecules. Unequivocal structure elucidation of biflavonoids and biflavanones by means of NMR spectroscopy is often complicated by the hindered rotation of the monomers around the C-C axis (atropisomerism), resulting in a high spectral complexity. In order to facilitate an unrestricted rotation, NMR spectra are usually recorded at elevated temperatures, commonly over 80 °C, which effects in a single set of resonance signals. However, under these conditions, one of the target compounds of this investigation, (2R,3S,2″R,3″R)-manniflavanone (1), undergoes degradation. Therefore, we demonstrated in the present study that the 1,1-ADEQUATE could be successfully used as a powerful alternative approach to confirm the C-C connectivities in 1, avoiding detrimental conditions. However, a moderate increase in temperature up to 50 °C was sufficient to deliver sharp signals in the proton NMR experiment of (2R,3S,2″R,3″R)-isomanniflavanone (2) and (2″R,3″R)-preussianone (3). In addition, two new compounds could be isolated, namely (2R,3S,2″R,3″R)-GB-2 7″-O-β-d-glucopyranoside (4) and (2R,3S,2″R,3″R)-manniflavanone-7″-O-β-d-glucopyranoside (5), and whose structures were elucidated by spectroscopic analysis including 1D and 2D NMR and mass spectrometry methods. The absolute configurations were determined by a combination of NMR and electronic circular dichroism (ECD) spectroscopy. The aforementioned compounds exhibited high anti-oxidative capacity in the H2O2 scavenging, hydrophilic Trolox equivalent antioxidant capacity (H-TEAC) and hydrophilic oxygen radical absorbance capacity (H-ORAC) assays.

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It's a promising approach for whom who work on biflavanones

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(+)- and (−)-Spiroreticulatine, A Pair of Unusual Spiro Bisheterocyclic Quinoline-imidazole Alkaloids from the South China Sea Sponge Fascaplysinopsis reticulata

(+)- and (−)-Spiroreticulatine, A Pair of Unusual Spiro Bisheterocyclic Quinoline-imidazole Alkaloids from the South China Sea Sponge Fascaplysinopsis reticulata | Natural Products Chemistry Breaking News | Scoop.it

A pair of novel bisheterocyclic quinoline-imidazole alkaloids, (+)- and (−)-spiroreticulatine (1), were isolated from the South China Sea sponge Fascaplysinopsis reticulata. The structures and absolute configurations were elucidated by comprehensive spectroscopic analysis, single-crystal X-ray diffraction, and quantum chemical calculation methods. Spiroreticulatine is the first example of a sponge-derived natural spiro quinoline-imidazole alkaloid that may derive from tryptophan and 1,3-dimethylurea. Compound 1 showed inhibitory activity on IL-2 production but inactive against normal tumor cell lines.


Org. Lett., Article ASAP
DOI: 10.1021/acs.orglett.5b01503
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Granuloside, A Unique Linear Homosesterterpene from the Antarctic Nudibranch Charcotia granulosa

Granuloside, A Unique Linear Homosesterterpene from the Antarctic Nudibranch Charcotia granulosa | Natural Products Chemistry Breaking News | Scoop.it

A new homosesterterpene with a unique linear skeleton, named granuloside (1), has been fully characterized from the Antarctic nudibranch Charcotia granulosa Vayssière, 1906 (Mollusca: Gastropoda). The planar structure of 1 was determined by extensive spectroscopic techniques on the methyl derivatives (1a and 1b), and the R absolute configuration at C-4 is suggested by comparison of experimental and calculated ECD spectra of 1b. Granuloside (1) is the first linear homosesterterpene skeleton ever reported and, despite the low molecular complexity, its chemical structure poses many questions about its biogenesis and origin in the nudibranch.


J. Nat. Prod., Article ASAP
DOI: 10.1021/acs.jnatprod.5b00378


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antiSMASH 3.0—a comprehensive resource for the genome mining of biosynthetic gene clusters

  1. Microbial secondary metabolism constitutes a rich source of antibiotics, chemotherapeutics, insecticides and other high-value chemicals. Genome mining of gene clusters that encode the biosynthetic pathways for these metabolites has become a key methodology for novel compound discovery. In 2011, we introduced antiSMASH, a web server and stand-alone tool for the automatic genomic identification and analysis of biosynthetic gene clusters, available athttp://antismash.secondarymetabolites.org. Here, we present version 3.0 of antiSMASH, which has undergone major improvements. A full integration of the recently published ClusterFinder algorithm now allows using this probabilistic algorithm to detect putative gene clusters of unknown types. Also, a new dereplication variant of the ClusterBlast module now identifies similarities of identified clusters to any of 1172 clusters with known end products. At the enzyme level, active sites of key biosynthetic enzymes are now pinpointed through a curated pattern-matching procedure and Enzyme Commission numbers are assigned to functionally classify all enzyme-coding genes. Additionally, chemical structure prediction has been improved by incorporating polyketide reduction states. Finally, in order for users to be able to organize and analyze multiple antiSMASH outputs in a private setting, a new XML output module allows offline editing of antiSMASH annotations within the Geneious software.

  2. Tilmann Weber1,*
  3. Kai Blin1
  4. Srikanth Duddela2
  5. Daniel Krug2,3
  6. Hyun Uk Kim1,4,
  7. Robert Bruccoleri5
  8. Sang Yup Lee1,4
  9. Michael A. Fischbach6
  10. Rolf Müller2,3,
  11. Wolfgang Wohlleben7,8
  12. Rainer Breitling9
  13. Eriko Takano9 and 
  14. Marnix H. Medema10,11,*

+Author Affiliations

Nucl. Acids Res. (2015)doi: 10.1093/nar/gkv437


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Recent advances in the use of vibrational chiroptical spectroscopic methods for stereochemical characterization of natural products

Recent advances in the use of vibrational chiroptical spectroscopic methods for stereochemical characterization of natural products | Natural Products Chemistry Breaking News | Scoop.it
Covering: 2000 to 2014This review covers conformational and configurational assignments in natural product molecules using chiroptical spectroscopy reported over the last 15 years. Special attention is given to vibrational optical activity methods associated with quantum mechanical calculations.


Nat. Prod. Rep., 2015, Advance Article


DOI: 10.1039/C5NP00027K

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Combining UHPLC-High Resolution MS and Feeding of Stable Isotope Labeled Polyketide Intermediates for Linking Precursors to End Products

Combining UHPLC-High Resolution MS and Feeding of Stable Isotope Labeled Polyketide Intermediates for Linking Precursors to End Products | Natural Products Chemistry Breaking News | Scoop.it

We present the results from stable isotope labeled precursor feeding studies combined with ultrahigh performance liquid chromatography-high resolution mass spectrometry for the identification of labeled polyketide (PK) end-products. Feeding experiments were performed with 13C8-6-methylsalicylic acid (6-MSA) and 13C14-YWA1, both produced in-house, as well as commercial 13C7-benzoic acid and 2H7-cinnamic acid, in species of Fusarium, Byssochlamys, Aspergillus, and Penicillium. Incorporation of 6-MSA into terreic acid or patulin was not observed in any of six evaluated species covering three genera, because the 6-MSA was shunted into (2Z,4E)-2-methyl-2,4-hexadienedioic acid. This indicates that patulin and terreic acid may be produced in a closed compartment of the cell and that (2Z,4E)-2-methyl-2,4-hexadienedioic acid is a detoxification product toward terreic acid and patulin. In Fusarium spp., YWA1 was shown to be incorporated into aurofusarin, rubrofusarin, and antibiotic Y. In A. niger, benzoic acid was shown to be incorporated into asperrubrol. Incorporation levels of 0.7–20% into the end-products were detected in wild-type strains. Thus, stable isotope labeling is a promising technique for investigation of polyketide biosynthesis and possible compartmentalization of toxic metabolites.


Department of Systems Biology, Technical University of Denmark, DK-2800 Kongens Lyngby, Denmark
J. Nat. Prod., Article ASAP
DOI: 10.1021/np500979d




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A New Metabolite with a Unique 4-Pyranone−γ-Lactam–1,4-Thiazine Moiety from a Hawaiian-Plant Associated Fungus

A New Metabolite with a Unique 4-Pyranone−γ-Lactam–1,4-Thiazine Moiety from a Hawaiian-Plant Associated Fungus | Natural Products Chemistry Breaking News | Scoop.it

An endophytic fungus Paraphaeosphaeria neglecta FT462 isolated from the Hawaiian-plant Lycopodiella cernua (L.) Pic. Serm produced one unusual compound (1, paraphaeosphaeride A) with the 4-pyranone−γ-lactam–1,4-thiazine moiety, along with two new compounds (2 and 3, paraphaeosphaerides B and C, respectively) and the known compound (4). Compounds 1–3 were characterized by NMR and MS spectroscopic analysis. The absolute configuration of the 3-position of compound 1 was determined as S by electronic circular dichroism (ECD) calculations. Compound 3 also showed STAT3 inhibition at 10 μM.


Org. Lett., Article ASAP
DOI: 10.1021/acs.orglett.5b01650
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Direct Protocol for Ambient Mass Spectrometry Imaging on Agar Culture

Direct Protocol for Ambient Mass Spectrometry Imaging on Agar Culture | Natural Products Chemistry Breaking News | Scoop.it

Herein we describe a new protocol that allows direct mass spectrometry imaging (IMS) of agar cultures. A simple sample dehydration leads to a thin solid agar, which enables the direct use of spray-based ambient mass spectrometry techniques. To demonstrate its applicability, metal scavengers siderophores were imaged directly from agar culture of S. wadayamensis, and well resolved and intense images were obtained using both desorption electrospray ionization (DESI) and easy ambient sonic-spray ionization (EASI) with well-defined selective spatial distributions for the free and the metal-bound molecules, providing clues for their roles in cellular metabolism.


Anal. Chem., Article ASAP
DOI: 10.1021/acs.analchem.5b01538


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Super Yeast Helps Remove Toxic Waste

Super Yeast Helps Remove Toxic Waste | Natural Products Chemistry Breaking News | Scoop.it
Searching through the Western Siberian peat bogs intrepid microbiologists have discovered a new strain of yeast. Taking the yeast back to the laboratory, it has been found that the yeast is very effective at waste water treatment – a natural cleaning-up agent. The new yeast is termed Yarrowia lipolytica Y-3492 and the discovery was made
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Geleganidines A–C, Unusual Monoterpenoid Indole Alkaloids from Gelsemium elegans

Geleganidines A–C, Unusual Monoterpenoid Indole Alkaloids from Gelsemium elegans | Natural Products Chemistry Breaking News | Scoop.it

The first rotameric monoterpenoid indole alkaloids (MIAs), 1a and 1b, and two unusual dimeric MIAs, 2 and 3, with new dimerization patterns, together with their putative biosynthetic intermediates 47, were isolated from the roots of Gelsemium elegans. Compounds 2 and 3 represent the first natural aromatic azo- and the first urea-linked dimeric MIAs, respectively. Their structures and absolute configurations were elucidated by means of NMR spectroscopy, single-crystal X-ray diffraction, and electronic circular dichroism data analyses. The interconverting mechanism of rotamers 1a and 1b was studied by density functional theory computation. Compounds 2 and 3 showed moderate cytotoxic activity against MCF-7 and PC-12 cells, respectively. In addition, a plausible biosynthesis pathway for the new alkaloids was proposed on the basis of the coexistence of their biosynthetic precursors.


J. Nat. Prod., Article ASAP
DOI: 10.1021/acs.jnatprod.5b00351
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New medicines from nature

New medicines from nature | Natural Products Chemistry Breaking News | Scoop.it
Thinkable.org


Inspire Australia Research Competition


Parkinson’s disease is a complex neurological condition that is incurable and its cause is not understood. An estimated 80, 000 Australians live with Parkinson’s disease and with our ageing population this number will almost double by 2030. There is a pressing and unmet need to understand the causes of typical Parkinson’s disease and to discover and develop effective therapies to halt or even reverse the progressive degeneration that is a hallmark of this disease. At the Griffith University Eskitis Institute for Drug Discovery we are utilizing two unique resources, Nature Bank and Neuro Bank to discover new therapies for Parkinson’s disease.


Vote for Asmaa on thinkable.org !

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Vote for Asmaa on thinkable.org !


Crowdfund a nice NP research project

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Biomimetic Total Synthesis of (−)-Penibruguieramine A Using Memory of Chirality and Dynamic Kinetic Resolution

Biomimetic Total Synthesis of (−)-Penibruguieramine A Using Memory of Chirality and Dynamic Kinetic Resolution | Natural Products Chemistry Breaking News | Scoop.it

The fully stereocontrolled total synthesis of (−)-penibruguieramine A, a naturally occurring marine pyrrolizidine alkaloid, is described in this study for the first time. The key synthetic sequence is the biomimetic aldol reaction of the proline pentaketide amide. The principles of “memory of chirality” (MOC) and “dynamic kinetic resolution” (DKR) are applied to this reaction for the asymmetric synthesis using proline as the only chiral source. A mechanistic rationale is discussed for the excellent stereochemical outcome in a protic solvent environment.


  1. Jae Hyun Kim, 
  2. Seokwoo Lee and
  3. Prof. Dr. Sanghee Kim*

Article first published online: 21 JUL 2015

DOI: 10.1002/ange.201504954



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Dereplicating and Spatial Mapping of Secondary Metabolites from Fungal Cultures in Situ

Dereplicating and Spatial Mapping of Secondary Metabolites from Fungal Cultures in Situ | Natural Products Chemistry Breaking News | Scoop.it

Ambient ionization mass spectrometry techniques have recently become prevalent in natural product research due to their ability to examine secondary metabolites in situ. These techniques retain invaluable spatial and temporal details that are lost through traditional extraction processes. However, most ambient ionization techniques do not collect mutually supportive data, such as chromatographic retention times and/or UV/vis spectra, and this can limit the ability to identify certain metabolites, such as differentiating isomers. To overcome this, the droplet–liquid microjunction–surface sampling probe (droplet–LMJ–SSP) was coupled with UPLC–PDA–HRMS–MS/MS, thus providing separation, retention times, MS data, and UV/vis data used in traditional dereplication protocols. By capturing these mutually supportive data, the identity of secondary metabolites can be confidently and rapidly assigned in situ. Using the droplet–LMJ–SSP, a protocol was constructed to analyze the secondary metabolite profile of fungal cultures without any sample preparation. The results demonstrate that fungal cultures can be dereplicated from the Petri dish, thus identifying secondary metabolites, including isomers, and confirming them against reference standards. Furthermore, heat maps, similar to mass spectrometry imaging, can be used to ascertain the location and relative concentration of secondary metabolites directly on the surface and/or surroundings of a fungal culture.


J. Nat. Prod., Article ASAP
DOI: 10.1021/acs.jnatprod.5b00268
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Insights into the chemical logic and enzymatic machinery of NRPS assembly lines

Insights into the chemical logic and enzymatic machinery of NRPS assembly lines | Natural Products Chemistry Breaking News | Scoop.it

Appreciation that some cyclic peptide antibiotics such as gramicidin S and tyrocidine were nonribosomally synthesized has been known for 50 years. The past two decades of research including advances in bacterial genetics, genomics, protein biochemistry and mass spectrometry have codified the principles of assembly line enzymology for hundreds of nonribosomal peptides and in parallel for thousands of polyketides. The advances in understanding the strategies used for chain initiation, elongation and termination from these assembly lines have revitalized natural product biosynthetic communities.


Nat. Prod. Rep., 2015, Advance Article


DOI: 10.1039/C5NP00035A

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Countercurrent Separation of Natural Products: An Update - Journal of Natural Products

Countercurrent Separation of Natural Products: An Update - Journal of Natural Products | Natural Products Chemistry Breaking News | Scoop.it

This work assesses the current instrumentation, method development, and applications in countercurrent chromatography (CCC) and centrifugal partition chromatography (CPC), collectively referred to as countercurrent separation (CCS). The article provides a critical review of the CCS literature from 2007 since our last review (J. Nat. Prod. 200871, 1489–1508), with a special emphasis on the applications of CCS in natural products research. The current state of CCS is reviewed in regard to three continuing topics (instrumentation, solvent system development, theory) and three new topics (optimization of parameters, workflow, bioactivity applications). The goals of this review are to deliver the necessary background with references for an up-to-date perspective of CCS, to point out its potential for the natural product scientist, and thereby to induce new applications in natural product chemistry, metabolome, and drug discovery research involving organisms from terrestrial and marine sources.



J. Nat. Prod., Article ASAP
DOI: 10.1021/np501065h
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LC-MS2-Based Dereplication of Euphorbia Extracts with Anti-Chikungunya Virus Activity

LC-MS2-Based Dereplication of Euphorbia Extracts with Anti-Chikungunya Virus Activity | Natural Products Chemistry Breaking News | Scoop.it

Recently, phorbol esters from Euphorbiaceae have been shown to elicit potent and selective antiviral activity on the replication of Chikungunya virus (CHIKV) in cell culture. With the objective to found new compounds with anti-CHIKV activities, 45 extracts from various plant parts of 11 Mediterranean Euphorbia and one Mercurialis species were evaluated for selective inhibition of CHIKV replication. All EtOAc extracts, especially those prepared from latex, exhibited significant and selective antiviral activity in a Chikungunya virus-cell-based assay. An LC-MS2 dereplication method was then developed to investigate whether known diterpenoids with anti-CHIKV activity, such as the potent anti-CHIKV 12-O-Tetradecanoylphorbol-13-acetate (TPA), phorbol-12,13-didecanoate, and prostratin as well as 24 other commercially available diterpenoids of tigliane-, ingenane-, and daphnane-type for which the anti-CHIKV activity have been established in advance (Nothias-Scaglia et al. 2015), were present in the Euphorbia extracts. Only ingenol-3-mebutate, 13-O-isobutyryl-12-deoxyphorbol-20-acetate, and ingenol-3,20-dibenzoate, all exhibiting weak anti-CHIKV activities, were detected in the EtOAc extracts of E. peplus, E. segetalis ssp. pinea, E. peplus, and E. pithyusa ssp. pithyusa. Given the potent anti-CHIKV activities of these Euphorbia extracts, the present study suggested that their antiviral activities are probably due to untargeted diterpenoids.


Available online 4 July 2015



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Eric Larson's curator insight, July 16, 11:37 AM

Anti-viral research.

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Combining Mass Spectrometric Metabolic Profiling with Genomic Analysis: A Powerful Approach for Discovering Natural Products from Cyanobacteria

Combining Mass Spectrometric Metabolic Profiling with Genomic Analysis: A Powerful Approach for Discovering Natural Products from Cyanobacteria | Natural Products Chemistry Breaking News | Scoop.it
An innovative approach was developed for the discovery of new natural products by combining mass spectrometric metabolic profiling with genomic analysis and resulted in the discovery of the columbamides, a new class of di- and trichlorinated acyl amides with cannabinomimetic activity. Three species of cultured marine cyanobacteria, Moorea producens 3L, Moorea producens JHB, and Moorea bouillonii PNG, were subjected to genome sequencing and analysis for their recognizable biosynthetic pathways, and this information was then compared with their respective metabolomes as detected by MS profiling. By genome analysis, a presumed regulatory domain was identified upstream of several previously described biosynthetic gene clusters in two of these cyanobacteria, M. producens 3L and M. producens JHB. A similar regulatory domain was identified in the M. bouillonii PNG genome, and a corresponding downstream biosynthetic gene cluster was located and carefully analyzed. Subsequently, MS-based molecular networking identified a series of candidate products, and these were isolated and their structures rigorously established. On the basis of their distinctive acyl amide structure, the most prevalent metabolite was evaluated for cannabinomimetic properties and found to be moderate affinity ligands for CB1.


J. Nat. Prod., Article ASAP
DOI: 10.1021/acs.jnatprod.5b00301
Publication Date (Web): July 7, 2015
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Probabilistic Model for Untargeted Peak Detection in LC–MS Using Bayesian Statistics

Probabilistic Model for Untargeted Peak Detection in LC–MS Using Bayesian Statistics | Natural Products Chemistry Breaking News | Scoop.it

We introduce a novel Bayesian probabilistic peak detection algorithm for liquid chromatography–mass spectroscopy (LC–MS). The final probabilistic result allows the user to make a final decision about which points in a chromatogram are affected by a chromatographic peak and which ones are only affected by noise. The use of probabilities contrasts with the traditional method in which a binary answer is given, relying on a threshold. By contrast, with the Bayesian peak detection presented here, the values of probability can be further propagated into other preprocessing steps, which will increase (or decrease) the importance of chromatographic regions into the final results. The present work is based on the use of the statistical overlap theory of component overlap from Davis and Giddings (Davis, J. M.; Giddings, J. Anal. Chem. 1983, 55, 418−424) as prior probability in the Bayesian formulation. The algorithm was tested on LC–MS Orbitrap data and was able to successfully distinguish chemical noise from actual peaks without any data preprocessing.


Anal. Chem., Article ASAP
DOI: 10.1021/acs.analchem.5b01521


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Indole Alkaloids from Chaetomium globosum

Indole Alkaloids from Chaetomium globosum | Natural Products Chemistry Breaking News | Scoop.it

Two new indole alkaloids chaetocochin J (1) and chaetoglobinol A (8), along with chetomin (2), chetoseminudin A (3), cochliodinol (9), and semicochliodinol (10), were isolated from the rice culture of the fungus Chaetomium globosum. Their structures were elucidated by spectral analysis. Three new epipolythiodioxopiperazines, chaetocochins G–I (57), were identified by the combination of UPLC and mass spectrometric analysis. Chaetocochin I contained two sulfur bridges, one formed by three sulfur atoms between C-3 and C-11a, and the other formed by four sulfur atoms between C-3′ and C-6′. Chaetocochin I was readily transformed into chetomin (2), chetoseminudin A (3), chaetocochin D (4), chaetocochin G (5), and chaetocochin H (6) by losing sulfur atoms. Compounds 13, and 8 exhibited antibacterial activities against Bacillus subtilis with MICs of 25, 0.78, 0.78, and 50 μg/mL, respectively, but not against Gram-negative bacterium (Escherichia coli). Compounds 2 and 8 were inactive against Candida albicans,Fusarium graminearumFusarium vasinfectumSaccharomyces cerevisiae, and Aspergillus niger even at the high concentrations of 200 and 100 μg/mL, respectively. Compound 8 showed free radical scavenging capacity against the 1,1-diphenyl-2-picryl-hydrazyl (DPPH) and 2,2′-azino-bis-3-ethylbenzothiazoline-6-sulfonic acid radical (ABTS+•), with IC50 values of 143.6 and 45.2 μM, respectively. The free radical scavenging capacity rates of compounds 13 on the DPPH and ABTS+• were less than 20% at the test concentrations (89.9–108.3 μM). The superoxide anion radical scavenging assay indicated that compounds 13, and 8 showed 14.8% (90.9 μM), 18.1% (90.9 μM), 51.5% (88.3 μM), and 30.4% (61.3 μM) superoxide anion radical scavenging capacity, respectively.


Guo-Bo Xu Gu He §Huan-Huan Bai Tao Yang Guo-Lin Zhang Lin-Wei Wu , and Guo-You Li
J. Nat. Prod., Article ASAP
DOI: 10.1021/np5007235




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Mapping Microbial Response Metabolomes for Induced Natural Product Discovery Chemical Biology

Mapping Microbial Response Metabolomes for Induced Natural Product Discovery Chemical Biology | Natural Products Chemistry Breaking News | Scoop.it

Dagmara K. Derewacz Brett C. Covington John A. McLean *, and Brian O. Bachmann *

Intergeneric microbial interactions may originate a significant fraction of secondary metabolic gene regulation in nature. Herein, we expose a genomically characterized Nocardiopsis strain, with untapped polyketide biosynthetic potential, to intergeneric interactions via coculture with low inoculum exposure to EscherichiaBacillusTsukamurella, and Rhodococcus. The challenge-induced responses of extracted metabolites were characterized via multivariate statistical and self-organizing map (SOM) analyses, revealing the magnitude and selectivity engendered by the limiting case of low inoculum exposure. The collected inventory of cocultures revealed substantial metabolomic expansion in comparison to monocultures with nearly 14% of metabolomic features in cocultures undetectable in monoculture conditions and many features unique to coculture genera. One set of SOM-identified responding features was isolated, structurally characterized by multidimensional NMR, and revealed to comprise previously unreported polyketides containing an unusual pyrrolidinol substructure and moderate and selective cytotoxicity. Designated ciromicin A and B, they are detected across mixed cultures with intergeneric preferences under coculture conditions. The structural novelty of ciromicin A is highlighted by its ability to undergo a diastereoselective photochemical 12-π electron rearrangement to ciromicin B at visible wavelengths. This study shows how organizing trends in metabolomic responses under coculture conditions can be harnessed to characterize multipartite cultures and identify previously silent secondary metabolism.

ACS Chem. Biol., Article ASAP
DOI: 10.1021/acschembio.5b00001


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