[Bjonnh.net]# _

Authors: Rasika S. Phansalkar, Charlotte Simmler, Jonathan BissonORCID , Shao-Nong Shen, David C. Lankin, James B. McAlpine, Matthias Niemitz, Guido F. PauliORCID
Journal: Journal of Natural Products (RoMEO status: White)
Subjects: Pharmacognosy Phytochemistry NMR qNMR HiFSA
Chemical standardization, along with morphological and DNA analysis ensures the authenticity and advances the integrity evaluation of botanical preparations. Achievement of a more comprehensive, metabolomic standardization requires simultaneous quantitation of multiple marker compounds. Employing quantitative 1H NMR (qHNMR), this study determined the total isoflavone content (TIfCo; 34.5–36.5% w/w) via multimarker standardization and assessed the stability of a 10-year-old isoflavone-enriched red clover extract (RCE). Eleven markers (nine isoflavones, two flavonols) were targeted simultaneously, and outcomes were compared with LC-based standardization.
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Authors: Guido F. PauliORCID , Matthias Niemitz, Jonathan BissonORCID , Michael W. Lodewyk, Cristian Soldi, Jared T. Shaw, Dean J. Tantillo, Jordy M. Saya, Klaas Vos, Roel A. Kleinnijenhuis, Henk Hiemstra, Shao-Nong Chen, James McAlpine, David C. Lankin, J. Brent Friesen
Journal: Journal of Organic Chemistry (RoMEO status: White)
Subjects: Pharmacognosy Phytochemistry NMR FID raw data Spin simulation
The revision of the structure of the sesquiterpene aquatolide from a bicyclo[2.2.0]hexane to a bicyclo[2.1.1]hexane structure using compelling NMR data, X-ray crystallography, and the recent confirmation via full synthesis exemplify that the achievement of “structural correctness” depends on the completeness of the experimental evidence. Archived FIDs and newly acquired aquatolide spectra demonstrate that archiving and rigorous interpretation of 1D 1H NMR data may enhance the reproducibility of (bio)chemical research and curb the growing trend of structural misassignments.
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Authors: Joo-Won Nam, Rasika Phansalkar, David C. Lankin, Jonathan BissonORCID , James McAlpine, Ariene A. Leme, Cristina M.P. Vidal, Benjamin Ramirez, Matthias Niemitz, Ana Bedran-Russo, Shao-Nong Chen, Guido F. PauliORCID
Journal: Journal of Organic Chemistry (RoMEO status: White)
Subjects: Pharmacognosy Phytochemistry Dentistry OPAC NMR
The ability of certain oligomeric proanthocyanidins (OPACs) to enhance the biomechanical properties of dentin involves collagen cross-linking of the 1.3–4.5 nm wide space via protein–polyphenol interactions. A systematic interdisciplinary search for the bioactive principles of pine bark has yielded the trimeric PAC, ent-epicatechin-(4β→8)-epicatechin-(2β→O→7,4β→8)-catechin (3), representing the hitherto most potent single chemical entity capable of enhancing dentin stiffness. Building the case from two congeneric PAC dimers, a detailed structural analysis decoded the stereochemistry, spatial arrangement, and chemical properties of three dentin biomodifiers.
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# Posters/

Dissemination of original NMR data enhances the reproducibility of natural product research

The acquisition of 1D 1H NMR (HNMR) spectra is one of earliest steps in characterizing natural products and other organic molecules. For publication, HNMR information usually is “converted” into a table format, and sometimes spectral plots are provided. However, this transformation is lossy and frequently insufficient for unambiguous dereplication. This ambiguity can even lead to structural revision, such as in the recent case of aquatolide (1), a sesquiterpene lactone from Asteriscus aquaticus.
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Authors: Guido F. PauliORCID , Shao-Nong Chen, David C. Lankin, Jonathan BissonORCID , Ryan J. Case, Lucas R. Chadwick, Tanja Gödecke, Taichi Inui, Aleksej Krunic, Birgit U. Jaki, James B. McAlpine, Shunyan Mo, José G. Napolitano, Jimmy Orjala, Juuso Lehtivarjo, Samuli-Petrus Korhonen, Matthias Niemitz
Journal: Journal of Natural Products (RoMEO status: White)
Subjects: Pharmacognosy Phytochemistry NMR Spin simulation
The present study demonstrates the importance of adequate precision when reporting the δ and J parameters of frequency domain 1H NMR (HNMR) data. Using a variety of structural classes (terpenoids, phenolics, alkaloids) from different taxa (plants, cyanobacteria), this study develops rationales that explain the importance of enhanced precision in NMR spectroscopic analysis and rationalizes the need for reporting Δδ and ΔJ values at the 0.1–1 ppb and 10 mHz level, respectively.
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