Structural Analysis of Natural Products

Přichystal, Jakub; Schug, Kevin A.; Lemr, Karel; Novák, Jiří; Havlı́ček, Vladimı́r

doi:10.1021/acs.analchem.6b02386

Cited by 46 publications

(41 citation statements)

References 98 publications

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“…For example, it is well-established that the structure elucidation of an unknown natural product is greatly facilitated by combining the unique information from NMR ( e.g., chemical shifts, coupling constants, NOEs, spin systems, etc. ) with MS ( e.g., exact mass [molecular formula], molecular fragments) [32, 33]. …”

Section: Introductionmentioning

confidence: 99%

“…This is an unfortunate and unavoidable outcome of our limited knowledge of the metabolome (the exact composition is currently unknown), the severe limitations in the software and databases available for metabolite identification, and the routine reliance on a single analytical method. Despite the routine application of NMR and MS to elucidate the structures of natural products for drug discovery [32, 33], most metabolic studies still rely on only NMR or MS spectral data for metabolite identification based on database searches [63]. Unfortunately, metabolic databases only contain, at most, a few thousand reference NMR or MS spectra of known metabolites.…”

Section: Introductionmentioning

confidence: 99%

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Beyond the paradigm: Combining mass spectrometry and nuclear magnetic resonance for metabolomics

Marshall

Powers

2017

Progress in Nuclear Magnetic Resonance Spectroscopy

176

136

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Metabolomics is undergoing tremendous growth and is being employed to solve a diversity of biological problems from environmental issues to the identification of biomarkers for human diseases. Nuclear magnetic resonance (NMR) and mass spectrometry (MS) are the analytical tools that are routinely, but separately, used to obtain metabolomics data sets due to their versatility, accessibility, and unique strengths. NMR requires minimal sample handling without the need for chromatography, is easily quantitative, and provides multiple means of metabolite identification, but is limited to detecting the most abundant metabolites (≥ 1 μM). Conversely, mass spectrometry has the ability to measure metabolites at very low concentrations (femtomolar to attomolar) and has a higher resolution (∼103-104) and dynamic range (∼103-104), but quantitation is a challenge and sample complexity may limit metabolite detection because of ion suppression. Consequently, liquid chromatography (LC) or gas chromatography (GC) is commonly employed in conjunction with MS, but this may lead to other sources of error. As a result, NMR and mass spectrometry are highly complementary, and combining the two techniques is likely to improve the overall quality of a study and enhance the coverage of the metabolome. While the majority of metabolomic studies use a single analytical source, there is a growing appreciation of the inherent value of combining NMR and MS for metabolomics. An overview of the current state of utilizing both NMR and MS for metabolomics will be presented.

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Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Beyond the paradigm: Combining mass spectrometry and nuclear magnetic resonance for metabolomics

Marshall

Powers

2017

Progress in Nuclear Magnetic Resonance Spectroscopy

176

136

View full text Add to dashboard Cite

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“…Characterisation of antimicrobial compounds extracted from TLC‐DB plates was accomplished using GC‐MS in addition to LC‐MS and NMR to potentially enhance detection of heat‐labile and non‐volatile compounds . GC‐MS analysis revealed that the antimicrobial fractions were mixtures of several compounds.…”

Section: Resultsmentioning

confidence: 99%

“…For example, the content of sesquiterpenes possessing an ( E,E)‐ 1,5‐cyclodecadiene structure in Vepris unifoliolata EO was underestimated by GC due to thermal rearrangement . Both liquid chromatography coupled with MS (LC‐MS) and proton ( 1 H) nuclear magnetic resonance (NMR) spectroscopy are conducted at ambient temperature, potentially improving detection of heat‐labile and non‐volatile components . However, these techniques are less commonly employed than GC‐MS in EO analysis.…”

Section: Introductionmentioning

confidence: 99%

Characterisation and screening of antimicrobial essential oil components against clinically important antibiotic‐resistant bacteria using thin layer chromatography‐direct bioautography hyphenated with GC‐MS, LC‐MS and NMR

Owen

White

Laird

2018

Phytochemical Analysis

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Introduction The antimicrobial activity of many essential oils (EOs) is well established, indicating that EOs may be a source of compounds for antimicrobial drug development. Thin layer chromatography‐direct bioautography (TLC‐DB) can quickly identify antimicrobial components in complex mixtures and can be applied to the screening of EOs for lead compounds. Objectives This study aimed to identify antimicrobial components of oregano, rosewood and cumin EOs against antibiotic‐sensitive and ‐resistant bacteria using TLC‐DB and a multi‐faceted approach of GC‐MS, LC‐MS and NMR techniques to characterise bioactive compounds. The study also aimed to quantify the antimicrobial activity of bioactive compounds in order to evaluate their potential for the development of therapies against antibiotic‐resistant bacteria. Materials and Methods EOs were eluted on TLC plates and sprayed with a suspension of Staphylococcus aureus, Enterococcus faecium, Escherichia coli or Pseudomonas aeruginosa (antibiotic‐sensitive and ‐resistant isolates). Zones of inhibition, visualised with iodonitrotetrazolium chloride, were subject to GC‐MS, LC‐MS and NMR to characterise the bioactive compounds. Results Seven compounds were identified from the three EOs using GC‐MS, while LC‐MS and NMR failed to detect the presence of any further non‐volatile or heat labile compounds. Carvacrol was most antimicrobial compound identified, with minimum inhibitory concentrations ranging 0.99–31.62 mM. Conclusion The identified antimicrobial compounds present in oregano, rosewood and cumin EOs including carvacrol may be candidates for the development of novel antimicrobial therapies against antibiotic‐resistant bacteria.

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“…The accurate determination of molecular mass supported by the corresponding isotope pattern is a widely used mass spectrometry approach for summary formula determination . The experimental isotope pattern is compared to the theoretical pattern calculated from an in silico ‐generated formula.…”

Section: Introductionmentioning

confidence: 99%

CycloBranch: An open tool for fine isotope structures in conventional and product ion mass spectra

et al. 2018

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Within the growing community of Fourier transform mass spectrometry users, the identification of fine isotope structure has become an indispensable method for molecular formula determination. In this work, the fine isotope envelopes for accessing the mutual ratio of 2 closely related pyoverdines in a mixture were used. Bacterial siderophores pyoverdines D and E cannot be easily separated via liquid chromatography-mass spectrometry because their structures differ in (de)amidation at the respective chromophore parts only. Their mutual ratio was determined in a mixture via nuclear magnetic resonance spectroscopy and semiquantitative mass spectrometry using our open-source software CycloBranch, which represents a genuine free tool supporting the determination of fine isotope structures in both conventional and product ion mass spectra. Native Bruker, Thermo, and Waters data formats are supported in addition to XML and plain text formats.

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Structural Analysis of Natural Products

Cited by 46 publications

References 98 publications

Beyond the paradigm: Combining mass spectrometry and nuclear magnetic resonance for metabolomics

Beyond the paradigm: Combining mass spectrometry and nuclear magnetic resonance for metabolomics

Characterisation and screening of antimicrobial essential oil components against clinically important antibiotic‐resistant bacteria using thin layer chromatography‐direct bioautography hyphenated with GC‐MS, LC‐MS and NMR

CycloBranch: An open tool for fine isotope structures in conventional and product ion mass spectra

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