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Gewählte Publikation:

Publikationstyp: Zeitschriftenaufsatz
Dokumentart: Originalarbeit

Publikationsjahr: 2012

AutorInnen: Pieri, V; Sturm, S; Seger, C; Franz, C; Stuppner, H

Titel: H-1 NMR-based metabolic profiling and target analysis: a combined approach for the quality control of Thymus vulgaris.

Quelle: Metabolomics (8), 2 335-346.



Autor/innen der Vetmeduni Vienna:

Franz Chlodwig

Beteiligte Vetmed-Organisationseinheiten
Institut für Tierernährung und funktionelle Pflanzenstoffe


Abstract:
The characterization of T. vulgaris plant material for quality control purposes was performed by NMR-based methods. Direct extraction of 141 T. vulgaris samples with DMSO-d (6) enabled the obtainment of crude extracts with a representative composition in terms of both volatile and non-volatile constituents. The acquisition of 600 MHz H-1 NMR spectra resulted in a dataset which was analyzed by a combination of metabolic profiling and target analysis approaches. Preliminary analysis of the H-1 NMR spectra was performed by principal component analysis, which revealed sample discrimination on a chemotype basis (thymol, carvacrol and linalool chemotypes). Further minor discriminative constituents were identified as p-cymene, gamma-terpinene, rosmarinic acid, and 3,4,3',4'-tetrahydroxy-5,5'-diisopropyl-2,2'-dimethylbiphenyl. Metabolite identification was accomplished by 1D and 2D NMR techniques and supported by spiking experiments. Fast dereplication of constituents not available as reference compounds was performed by HPLC-SPE-NMR experiments. A targeted approach based on qHNMR was validated for quantification of the identified secondary metabolites. Validation was performed in terms of precision (intra-day RSD a parts per thousand currency sign 4.51%, inter-day RSD a parts per thousand currency sign 4.18%), repeatability (RSD a parts per thousand currency sign 2.30%), accuracy (recovery rates within 93.4 and 103.4%), linearity (correlation coefficients a parts per thousand yen 0.9990), robustness, and stability. The amount of the dominant monoterpene in thymol, carvacrol, and linalool chemotypes was respectively found to be within 0.4-2.6, 0.7-2.3, and 1.1-3.6% (w/w). Variable amounts of the precursors p-cymene and gamma-terpinene were found in thymol and carvacrol chemotypes. The highest amount of rosmarinic acid and 3,4,3',4'-tetrahydroxy-5,5'-diisopropyl-2,2'-dimethylbiphenyl in the analyzed samples was respectively 4.6 and 0.4% (w/w). Since quantification is performed on a weight basis, the essential oil content can be estimated based on the sum of the quantified monoterpenes. The NMR-based analysis of T. vulgaris represents a more comprehensive approach in comparison to traditional chromatographic methods such as GC and LC, respectively employed for the analysis of volatile and non-volatile constituents. Further advantages lie in the simple sample preparation, rapidity and reproducibility of the NMR analysis.


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