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Publikationen - Natur- und Wirkstoffchemie

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Publikation

Farag, M. A.; Shakour, Z. T.; Lübken, T.; Frolov, A.; Wessjohann, L. A.; Mahrous, E.; Unraveling the metabolome composition and its implication for Salvadora persica L. use as dental brush via a multiplex approach of NMR and LC–MS metabolomics J. Pharm. Biomed. Anal. 193, 113727, (2021) DOI: 10.1016/j.jpba.2020.113727

Salvadora persica L. (toothbrush tree, Miswak) is well recognized in most Middle Eastern and African countries for its potential role in dental care, albeit the underlying mechanism for its effectiveness is still not fully understood. A comparative MS and NMR metabolomics approach was employed to investigate the major primary and secondary metabolites composition of S. persica in context of its organ type viz., root or stem to rationalize for its use as a tooth brush. NMR metabolomics revealed its enrichment in nitrogenous compounds including proline-betaines i.e., 4-hydroxy-stachydrine and stachydrine reported for the first time in S. persica. LC/MS metabolomics identified flavonoids (8), benzylurea derivatives (5), butanediamides (3), phenolic acids (8) and 5 sulfur compounds, with 21 constituents reported for the first time in S. persica. Principal component analysis (PCA) and hierarchical cluster analysis (HCA) of either NMR or LC/MS dataset clearly separated stem from root specimens based on nitrogenous compounds abundance in roots and is justifying for its preference as toothbrush versus stems. The presence of betaines at high levels in S. persica (9−12 μg/mg dry weight) offers novel insights into its functioning as an osmoprotectant that maintains the hydration of oral mucosa. Additionally, the previously described anti-inflammatory activity of stachydrine along with the antimicrobial effects of sulfonated flavonoids, benzylisothiocynate and ellagic acid derivatives are likely contributors to S. persica oral hygiene health benefits. Among root samples, variation in sugars and organic acids levels were the main discriminatory criterion. This study provides the first standardization of S. persica extract using qNMR for further inclusion in nutraceuticals.
Publikation

Farag, M. A.; Mahrous, E. A.; Lübken, T.; Porzel, A.; Wessjohann, L.; Classification of commercial cultivars of Humulus lupulus L. (hop) by chemometric pixel analysis of two dimensional nuclear magnetic resonance spectra Metabolomics 10, 21-32, (2014) DOI: 10.1007/s11306-013-0547-4

The development of fast and effective spectroscopic methods that can detect most compounds in an untargeted manner is of increasing interest in plant extracts fingerprinting or profiling projects. Metabolite fingerprinting by nuclear magnetic resonance (NMR) is a fast growing field which is increasingly applied for quality control of herbal products, mostly via 1D 1H NMR coupled to multivariate data analysis. Nevertheless, signal overlap is a common problem in 1H NMR profiles that hinders metabolites identification and results in incomplete data interpretation. Herein, we introduce a novel approach in coupling 2D NMR datasets with principal component analysis (PCA) exemplified for hop resin classification. Heteronuclear multiple bond correlation (HMBC) profile maps of hop resins (Humulus lupulus) were generated for a comparative study of 13 hop cultivars. The method described herein combines reproducible metabolite fingerprints with a minimal sample preparation effort and an experimental time of ca. 28 min per sample, comparable to that of a standard HPLC run. Moreover, HMBC spectra provide not only unequivocal assignment of hop major secondary metabolites, but also allow to identify several isomerization and degradation products of hop bitter acids including the sedative principal of hop (2-methylbut-3-en-2-ol). We do believe that combining 2D NMR datasets to chemometrics, i.e. PCA, has great potential for application in other plant metabolome projects of (commercially relevant) nutraceuticals and or herbal drugs.
Publikation

Schmidts, V.; Fredersdorf, M.; Lübken, T.; Porzel, A.; Arnold, N.; Wessjohann, L.; Thiele, C. M.; RDC-Based Determination of the Relative Configuration of the Fungicidal Cyclopentenone 4,6-Diacetylhygrophorone A12 J. Nat. Prod. 76, 839-844, (2013) DOI: 10.1021/np300728b

The hygrophorones, a class of cyclopentenones isolated from fruiting bodies of the genus Hygrophorus (basidiomycetes), show promising antifungal activity. While the constitution of 4,6-diacetylhygrophorone A(12) (3) and the relative configuration of the stereogenic centers in the cyclopentenone ring were elucidated using standard NMR and MS techniques, the relative configuration of the exocyclic stereogenic center could not be assigned. By introducing a sample of 3 into an alignment medium and measuring anisotropic NMR parameters, namely, residual dipolar couplings, we were able to unambiguously determine the relative configuration of all three stereogenic centers in 4,6-diacetylhygrophorone A(12) simultaneously by fitting several structure proposals to the experimental data.
Publikation

Teichert, A.; Lübken, T.; Schmidt, J.; Kuhnt, C.; Huth, M.; Porzel, A.; Wessjohann, L.; Arnold, N.; Determination of β‐carboline alkaloids in fruiting bodies of Hygrophorus spp. by liquid chromatography/electrospray ionisation tandem mass spectrometry Phytochem. Anal. 19, 335-341, (2008) DOI: 10.1002/pca.1057

The β ‐carboline alkaloids harmane (1 ) and norharmane (2 ) were isolated from fruiting bodies of Hygrophorus eburneus (Bull.) Fr. as well as brunnein A (3 ) from Hygrophorus hyacinthinus Quél. (Tricholomataceae, Agaricales) for the first time. Their occurrence within the genus was investigated using liquid chromatography/electrospray ionisation tandem mass spectrometric methods, especially by selected reaction monitoring. Based on these results their chemotaxonomical relevance is discussed.
Publikation

Lübken, T.; Arnold, N.; Wessjohann, L.; Böttcher, C.; Schmidt, J.; Analysis of fungal cyclopentenone derivatives from Hygrophorus spp. by liquid chromatography/electrospray-tandem mass spectrometry J. Mass Spectrom. 41, 361-371, (2006) DOI: 10.1002/jms.996

Fruitbodies of the genus Hygrophorus (Basidiomycetes) contain a series of anti‐biologically active compounds. These substances named hygrophorones possess a cyclopentenone skeleton. LC/ESI‐MS/MS presents a valuable tool for the identification of such compounds. The mass spectral behaviour of typical selected members of this group under positive and negative ion electrospray conditions is discussed. Using the ESI collision‐induced dissociation (CID) mass spectra of the [M + H]+ and [M − H]− ions, respectively, the compounds can be classified with respect to the substitution pattern at the cyclopentenone ring and the type of oxygenation at C‐6 (hydroxy/acetoxy or oxo function) of the side chain. The elemental composition of the fragment ions was determined by ESI‐QqTOF measurements. Thus, in case of the negative ion CID mass spectra an unusual loss of CO2 from the deprotonated molecular ions could be observed.
Publikation

Teichert, A.; Lübken, T.; Schmidt, J.; Porzel, A.; Arnold, N.; Wessjohann, L.; Unusual Bioactive 4-Oxo-2-alkenoic Fatty Acids from Hygrophorus eburneus Z. Naturforsch. B 60, 25-32, (2005) DOI: 10.1515/znb-2005-0105

From fruit bodies of the basidiomycete Hygrophorus eburneus (Bull.: Fr.) Fr. (Tricholomataceae) eight fatty acids (C16, C18) with γ -oxocrotonate partial structure could be isolated. Initial tests demonstrate their bactericidal and fungicidal activity. The structures of (2E,9E)-4-oxooctadeca- 2,9,17-trienoic acid (1), (2E,11Z)-4-oxooctadeca-2,11,17-trienoic acid (2), (E)-4-oxohexadeca-2,15- dienoic acid (3), (E)-4-oxooctadeca-2,17-dienoic acid (4), (2E,9E)-4-oxooctadeca-2,9-dienoic acid (5), (2E,11Z)-4-oxooctadeca-2,11-dienoic acid (6), (E)-4-oxohexadec-2-enoic acid (7), and (E)-4- oxooctadec-2-enoic acid (8) were elucidated on the basis of their spectroscopic data.
Publikation

Teichert, A.; Lübken, T.; Kummer, M.; Besl, H.; Haslberger, H.; Arnold, N.; Bioaktive Sekundärmetaboliten aus der Gattung Hygrophorus (Basidiomycetes) Z. Mykol. 71, 53-61, (2005)

Die fungizide Wirkung von verschiedenen Rohextrakten von 23 Arten der Gattung Hygrophorus gegen Cladosporium cucumerinum wird gezeigt. Als Wirkprinzip konnten ungewöhnliche Fettsäuren und die Hygrophorone A-G identifiziert werden.
Publikation

Lübken, T.; Schmidt, J.; Porzel, A.; Arnold, N.; Wessjohann, L.; Hygrophorones A–G: fungicidal cyclopentenones from Hygrophorus species (Basidiomycetes) Phytochemistry 65, 1061-1071, (2004) DOI: 10.1016/j.phytochem.2004.01.023

Twenty new 5-(hydroxyalkyl)-2-cyclopentenone derivatives (hygrophorones) could be isolated from Hygrophorus latitabundus, H. olivaceoalbus, H. persoonii, and H. pustulatus. Their fungicidal activity was exemplarily tested. The hygrophorones have structural similarities to the antibiotic pentenomycin. Chemically, hygrophorones are 2-cyclopentenones with hydroxy or acetoxy substituents at C-4 and/or C-5. An odd-numbered 1′ oxidized alkyl chain (C11, C13, C15, or C17) is attached at C-5. In addition, from H. persoonii the new γ-butyrolactone derivative [5-(E)-2-hydroxytetradexylidene-5H-furan-2-one] could be isolated. Some hygrophorones are responsible for the color reaction of the stipes of these fungi upon treatment with potassium hydroxide solution. Structural elucidations are based on 1D (1H, 13C) and 2D (COSY, NOESY, HSQC, HMBC) NMR spectroscopic analyses as well as HR-FT-ICR-MS investigations.A series of new cyclopentenone derivatives and butyrolactones with antifungical activity could be isolated from fruit bodies of the basidiomyceteous genus Hygrophorus. Structural elucidations are based on 1D and 2D NMR spectroscopic analyses as well as HR-FT-ICR-MS investigations.
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