The flavonoid class encompasses over 700 distinct structural variants, all of which have been demonstrated to confer a multitude of beneficial effects on human health. Given the correlation between oxidative stress and over 100 diseases, including neurodegenerative, cardiovascular, and inflammatory diseases, it is a valuable target for the development of therapeutic agents. This study examined the effects of prenylated chalcones and flavanones derived from hops (Humulus lupulus L.), including xanthohumol, xanthohumol A, and C, as well as isoxanthohumol, 6- and 8-prenylnaringenin, and 8-geranylnaringenin, on cell viability and on revising the effect of sodium nitroprusside (SNP) on cell viability in the neuroblastoma cell line SH-SY5Y. The lowest IC50 (10.14–20.42 µM) was observed in treatment with chalcones. With regard to the protective effect against SNP, a structure-activity relationship of prenylated and geranylated flavanones indicated that the extension of the prenyl side chain is beneficial for the protective effect of prenylated flavanones against SNP treatment. In accordance with the aforementioned methodology, 8-farnesylnaringenin, comprising a chain of three isoprene units, was synthesized and the effect on cell viability and protection against SNP-induced reduction of cell viability was subsequently evaluated. The strongest impact on cell viability (IC50) was observed for 8-farnesylnaringenin, which also demonstrated the most robust protective effect (25 %).
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Jan-Simon Jeshua Friedrichs,
Kai Stirnweiß,
Corinna Urmann,
Volker Sieber
Pyrrole-2,5-dicarboxylic acid (PDCA) and its N-substituted derivatives are interesting building blocks for macromolecular applications. However, only a few published procedures describe the synthesis of PDCA derivatives. These procedures often suffer from low yields, the formation of unwanted side products, harsh reaction conditions, the use of toxic and expensive reagents, or the unavailability of certain derivatives. Here, a facile and scalable six-step synthetic route is described, starting from biobased d-galactaric acid, for the production of N-alkylated and N-arylated PDCAs, achieving total yields of up to 45%. In addition, the E-factor of the presented synthesis route is decreased by a factor of 14 compared to already established methods.
Chalcones represent a privileged scaffold in medicinal chemistry, with pyranochalcones, featuring an additional chromane-like ring, identified as neurogenic and neuroprotective. Reporter gene assays, often used to study these and other effects, can produce false positives due to firefly luciferase stabilisation by inhibitors. The present study demonstrates that pyranochalcones inhibit firefly luciferase activity, with inhibition levels ranging from none to 100% and IC50 values of 7.82 µM to 92.99 µM. Furthermore, molecular docking offers potential structure-based explanations for the observed selectivity of compounds towards firefly luciferase inhibition. Even slight modifications in the molecular structure lead to significant changes in luciferase inhibition, underscoring the importance of these findings for understanding structure-activity relationships in reporter gene assays. Accordingly, caution is advised when using reporter gene assays based on firefly luciferase and pyranochalcones, as the IC50 values are within the range of concentrations commonly used in both in vivo and in vitro assays.
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Ekaterina-Michaela Tomou,
Oliver Engler,
Antonios Chrysagyris,
Nikolaos Tzortzakis,
Helen Skaltsa,
Corinna Urmann
IntroductionThe SARS‐CoV‐2 pandemic has revealed a deficiency in antiviral agents. Plants, traditionally used for respiratory infections, are valuable sources of antiviral compounds. Such a plant is the Sideritis L. taxa (mountain tea), traditionally used against cold and cough.ObjectivesAccordingly, this study aimed to investigate the potential protective effects of dichloromethane extracts from Sideritis species against SARS‐CoV‐2.Materials and MethodsEight Sideritis extracts were tested in an in vitro pretreatment assay to assess the protective effect against SARS‐CoV‐2. Therefore, infectious virus particles were pre‐incubated with the extract, then incubated with Vero E6 cells to finally measure cell viability as a surrogate for virus infection. Untargeted analyses (GC–MS and LC‐PDA‐HRESIMS) were performed to determine metabolite profiles.ResultsUsing an orthogonal approach that combines untargeted metabolomics and biological data from a screening assay, we characterized the phytochemical profiles of the different extracts and prioritized samples for targeted isolation. The dichloromethane extract of Sideritis cypria exhibited a notable protective effect. Untargeted analysis revealed coumarins as key compounds, with varying amounts across Sideritis species. Accordingly, fractionation of extract resulted in the isolation of two coumarin derivatives. Structure elucidation was performed using one‐ and two‐dimensional nuclear magnetic resonance experiments. The coumarin, more abundant in S. cypria , demonstrated a slight protective effect in the SARS‐CoV‐2 pretreatment assay.ConclusionThis study highlights the antiviral effects of Sideritis taxa, although further investigations are necessary to clarify the full potential of the herb. Additionally, the methodology presented herein can serve as a valuable resource for future phytochemical investigations focused on coumarin content within Sideritis genus.
Pyrrole-2,5-dicarboxylic acid (PDCA) is a heterocyclic aromatic dicarboxylic acid that may emerge as a new monomer for polyester production. Compared to its structurally related and bio-based furan-2,5-dicarboxylic acid (FDCA) that is already used for the production of polyethylene furanoate (PEF), PDCA shows excellent potential as its nitrogen can be targeted for further derivatization, thus enabling tuning of the properties of a PDCA containing polymer. In light of this, we recognized the need to explore efficient synthetic approaches for producing PDCAs in high yields. Here, we report a five-step synthesis route for N-substituted PDCAs starting from pyrrole, with total yields up to 42 %. The synthetic approach allowed the introduction of several different functional moieties to the pyrrole nitrogen, such as aliphatic saturated and unsaturated side-chains, as well as benzylic groups.
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Ekaterina-Michaela Tomou,
Katerina Goula,
Helen Skaltsa,
Corinna Urmann
The present study focuses on the chemical composition of the infusions of Sideritis raeseri subsp. raeseri from cultivated and wild populations using NMR, LC-DAD, LC-HRESIMS, and GC-MS techniques, to reveal possible differences. Mainly carbohydrates, flavonoids, and phenylethanoid glycosides were detected in the 1H-NMR spectra of both infusions. In the GC-MS analysis, carbohydrates were shown to be the main constituents in both infusions. Caffeic acid was found in traces only in the cultivated sample, while quinic and chlorogenic acids were detected in both samples. Further investigation by LC-HRESIMS unveiled the same constituents with only slight differences in the amounts. Although the Sideritis samples originated from wild and cultivated populations, similar metabolic profiles were observed in the infusions.
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Maximilian Rothammer,
Cordt Zollfrank,
Corinna Urmann
Berechtigungen: Peer Reviewed
Biocompatible coatings based on photo-crosslinkable cellulose derivatives (2023) Elsevier 250 , S. 126063.
DOI: 10.1016/j.ijbiomac.2023.126063
Ekaterina-Michaela Tomou,
Lara Bieler,
Sébastien Couillard-Després,
Helen Skaltsa,
Corinna Urmann
Berechtigungen: Peer Reviewed
Metabolic Fingerprinting of Different Sideritis Taxa Infusions and Their Neurogenic Activity (2023) Planta Medica 89 (11), S. 1087-1096.
DOI: 10.1055/a-2072-2351
Corinna Urmann,
Lara Bieler,
Michael Hackl,
Olivia Chia-Leeson,
Sébastien Couillard-Després,
Herbert Riepl
Berechtigungen: Open Access
Berechtigungen: Peer Reviewed
Semi-Synthesis of Different Pyranoflavonoid Backbones and the Neurogenic Potential (2023) molecules 28 (10), S. 4023.
DOI: 10.3390/molecules28104023
Antonius Amm,
Alexandra Nicola Egger,
Klaus Menrad,
Corinna Urmann,
Agnes Emberger-Klein
This report gives details about the medical use and technology of neuroregenerative hop ingredients as well as conumer interest in related new plant-derived medicinal products.
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Agnes Emberger-Klein,
Kristin Werner,
Corinna Urmann,
Herbert Riepl,
Klaus Menrad
Synthetische oder mithilfe von Palmöl gewonnene Myristinsäure soll durch Ölsäure ersetzt werden, dazu wird ein Katalysator entwickelt, der die in Ölsäure vorhandene Doppelbindung zu verschieben …
Der Reststoff Gerbstoffextrakt soll aufgereinigt werden und als Quelle für natürliche Antioxidantien in Kosmetik und Lebensmitteln als Stabilisator, Konservierungsstoff oder aufgrund ihrer positiven …
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