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Publikation

Lam, Y. T. H.; Hoppe, J.; Dang, Q. N.; Porzel, A.; Soboleva, A.; Brandt, W.; Rennert, R.; Hussain, H.; Davari, M. D.; Wessjohann, L.; Arnold, N.; Purpurascenines A–C, azepino-indole alkaloids from Cortinarius purpurascens: Isolation, biosynthesis, and activity studies on the 5-HT2A receptor J. Nat. Prod. 86, 1373-1384, (2023) DOI: 10.1021/acs.jnatprod.2c00716

Three previously undescribed azepino-indole alkaloids, named purpurascenines A−C (1−3), together with the new-to-nature 7-hydroxytryptophan (4) as well as two known compounds, adenosine (5) and riboflavin (6), were isolated from fruiting bodies of Cortinarius purpurascens Fr. (Cortinariaceae). The structures of 1−3 were elucidated based on spectroscopic analyses and ECD calculations. Furthermore, the biosynthesis of purpurascenine A (1) was investigated by in vivo experiments using 13C-labeled sodium pyruvate, alanine, and sodium acetate incubated with fruiting bodies of C. purpurascens. The incorporation of 13C into 1 was analyzed using 1D NMR and HRESIMS methods. With [3-13C]-pyruvate, a dramatic enrichment of 13C was observed, and hence a biosynthetic route via a direct Pictet−Spengler reaction between α-keto acids and 7-hydroxytryptophan (4) is suggested for the biosynthesis of purpurascenines A−C (1−3). Compound 1 exhibits no antiproliferative or cytotoxic effects against human prostate (PC-3), colorectal (HCT-116), and breast (MCF-7) cancer cells. An in silico docking study confirmed the hypothesis that purpurascenine A (1) could bind to the 5-HT2A serotonin receptor’s active site. A new functional 5-HT2A receptor activation assay showed no functional agonistic but some antagonistic effects of 1 against the 5-HT-dependent 5-HT2A activation and likely antagonistic effects on putative constitutive activity of the 5-HT2A receptor.
Publikation

Corrêa dos Santos, C. H.; Stark, P.; Rizzo, P.; Franke, K.; Wessjohann, L.; Prenylated acylphloroglucinol alcohols and peroxides from Hypericum coris Phytochem. Lett. 57, 11-15, (2023) DOI: 10.1016/j.phytol.2023.07.011

Two so far undescribed prenylated acylphloroglucinol derivatives were isolated from Hypericum coris (hypercorisins A-B) together with their two, also yet undescribed, peroxide derivatives (hypercorisins C-D), and seven known compounds (2-geranyloxy-1-(2-methylpropanoyl)-phloroglucinol, sucrose, vanillic acid 4-O-β-D-glucoside, chlorogenic acid, neochlorogenic acid, shikimic acid, quercitrin). The structures were determined by means of 1D and 2D NMR experiments and high-resolution mass spectrometry. Hypercorisins A, B and D induced complete inhibition of the gram-positive bacterium Bacillus subtilis at the highest concentration tested (100 μM) but showed no appreciable antibacterial effect on the gram-negative Aliivibrio fischeri nor cytotoxic activity on PC-3 or HCT-116 cancer cell lines.
Publikation

El-Hawary, E. A.; Zayed, A.; Laub, A.; Modolo, L. V.; Wessjohann, L.; Farag, M. A.; How does LC/MS compare to UV in coffee authentication and determination of antioxidant effects? Brazilian and Middle Eastern coffee as case studies Antioxidants 11, 131, (2022) DOI: 10.3390/antiox11010131

Coffee is a popular beverage owing to its unique flavor and diverse health benefits. The current study aimed at investigating the antioxidant activity, in relation to the phytochemical composition, of authenticated Brazilian green and roasted Coffea arabica and C. robusta, along with 15 commercial specimens collected from the Middle East. Ultra-high-performance liquid chromatography coupled to high-resolution mass spectrometry (UHPLC-ESI–HRMS) and UV spectrometry were employed for profiling and fingerprinting, respectively. With the aid of global natural product social molecular networking (GNPS), a total of 88 peaks were annotated as belonging to different chemical classes, of which 11 metabolites are reported for the first time in coffee seeds. Moreover, chemometric tools showed comparable results between both platforms, with more advantages for UV in the annotation of roasting products, suggesting that UV can serve as a discriminative tool. Additionally, antioxidant assays coupled with the UHPLC-ESI–HRMS dataset using partial least-squares discriminant analysis (PLS-DA) demonstrated that caffeoylquinic acid and caffeine were potential antioxidant markers in unroasted coffee versus dicaffeoyl quinolactone and melanoidins in roasted coffee. The study presents a multiplex metabolomics approach to the quality control of coffee, one of the most consumed beverages.
Publikation

Baky, M. H.; Elshahed, M.; Wessjohann, L.; Farag, M. A.; Interactions between dietary flavonoids and the gut microbiome: a comprehensive review British Journal of Nutrition 128, 577 - 591, (2022) DOI: 10.1017/s0007114521003627

Abstract Flavonoids are natural polyphenol secondary metabolites that are widely produced in planta. Flavonoids are ubiquities in human dietary intake and exhibit a myriad of health benefits. Flavonoids-induced biological activities are strongly influenced by their in situ availability in the human GI tract, as well as the levels of which are modulated by interaction with the gut bacteria. As such, assessing flavonoids–microbiome interactions is considered a key to understand their physiological activities. Here, we review the interaction between the various classes of dietary flavonoids (flavonols, flavones, flavanones, isoflavones, flavan-3-ols and anthocyanins) and gut microbiota. We aim to provide a holistic overview of the nature and identity of flavonoids on diet and highlight how flavonoids chemical structure, metabolism and impact on humans and their microbiomes are interconnected. Emphasis is placed on how flavonoids and their biotransformation products affect gut microbiota population, influence gut homoeostasis and induce measurable physiological changes and biological benefits.
Publikation

Leonova, T.; Shumilina, J.; Kim, A.; Frolova, N.; Wessjohann, L.; Bilova, T.; Frolov, A.; Agar-based polyethylene glycol (PEG) infusion model for pea (Pisum sativum L.) — perspectives of translation to legume crop plants Biol. Commun. 67, 236-244, (2022) DOI: 10.21638/spbu03.2022.309

Due to the oncoming climate changes water deficit represents one of the most important abiotic stressors which dramatically affects crop productivity worldwide. Because of their importance as the principal source of food protein, legumes attract a special interest of plant scientists. Moreover, legumes are involved in symbiotic association with rhizobial bacteria, which is morphologically localized to root nodules. These structures are critical for fixation of atmospheric nitrogen and highly sensitive to drought. Therefore, new drought-tolerant legume cultivars need to be developed to meet the growing food demand. However, this requires a comprehensive knowledge of the molecular mechanisms behind the plant stress response. To access these mechanisms, adequate and reliable drought stress models need to be established. The agar-based polyethylene glycol (PEG) infusion model allows a physiologically relevant reduction of soil water potential (Ψw), although it is restricted to seedlings and does not give access to proteomics and metabolomics studies. Earlier, we successfully overcame this limitation and optimized this model for mature Arabidopsis plants. Here we make the next step forward and address its application to one of the major crop legumes — pea. Using a broad panel of physiological and biochemical markers, we comprehensively prove the applicability of this setup to legumes. The patterns of drought-related physiological changes are well-interpretable and generally resemble the stress response of plants grown in soil-based stop-watering models. Thus, the proposed model can be efficiently used in the study of stress-related metabolic adjustment in green parts, roots and root nodules of juvenile and flowering plants.
Publikation

Corrêa dos Santos, C. H.; Geraldo de Carvalho, M.; Laub, A.; Franke, K.; Wessjohann, L.; UHPLC-ESI-Orbitrap-HR-MS analysis of cyclopeptide alkaloids from Ziziphus joazeiro Nat. Prod. Commun. 16, 1-13, (2021) DOI: 10.1177/1934578x211054955

Ziziphus joazeiro Mart., popularly known as “juazeiro”, is a tree widely found in the northeast of Brazil. It is commonly used as an anti-inflammatory, antibacterial, antifungal, and analgesic agent. The stem extract exhibited, beside cytotoxic properties, substantial activity against the Gram-negative bacterium Allivibrio fischeri. UHPLC-ESI-Orbitrap-HR-MS analysis of the alkaloidal fraction of the crude methanolic stem extract of this species enabled the detection and putative identification of sixteen cyclopeptide alkaloids (CPAs), including four possibly new structures. According to the MS2 fragmentation analysis, from the sixteen identified CPAs, three possess a type-Ia1, one a type-Ia2, and twelve a type-Ib cyclopeptide alkaloid core. The structures of paliurine-C and -D were supported by NMR data.
Publikation

Neubauer, P. R.; Pienkny, S.; Wessjohann, L. A.; Wessjohann, L.; Brandt, W.; Sewald, N.; Predicting the substrate scope of the flavin‐dependent halogenase BrvH ChemBioChem 21, 3282–3288, (2020) DOI: 10.1002/cbic.202000444

The recently described flavin‐dependent halogenase BrvH is able to catalyze both bromination and chlorination of indole, but shows significantly higher bromination activity. BrvH was annotated as a tryptophan halogenase, but does not accept tryptophan as a substrate. Its native substrate remains unknown. A predictive model with the data available for BrvH was analysed. A training set of compounds tested in vitro was docked into the active site of a complete protein model based on the X‐ray structure of BrvH. The atoms not resolved experimentally have been modelled using molecular mechanics force fields to obtain this protein model. Furthermore, docking poses for the substrates and known non‐substrates have been calculated. Parameters like distance, partial charge, and hybridization state have been analysed to derive rules for prediction of activity. With this model for activity of the BrvH, a virtual screening suggested several structures for potential substrates. Some of the thus preselected compounds were tested in vitro and several could be verified as convertible substrates. Based on information on halogenated natural products, a new dataset was created to specifically search for natural products as substrates/products, and virtual screening in this database yielded further hits.
Bücher und Buchkapitel

Restrepo, S.; Samper, C.; di Palma, F.; Hodson, E.; Torres, M.; Reol, E. M.; Eddi, M.; Wessjohann, L.; Jaramillo, G. P.; et al., .; Colombia hacia una sociedad del conocimiento. Reflexiones y propuestas 1-450, (2020) ISBN: 978-958-5135-12-3

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Bücher und Buchkapitel

Francioso, A.; Franke, K.; Villani, C.; Mosca, L.; d’Erme, M.; Frischbutter, S.; Brandt, W.; Sanchez-Lamar, A.; Wessjohann, L.; Insights into the Phytochemistry of the Cuban Endemic Medicinal Plant Phyllanthus orbicularis: Fideloside, a Novel Bioactive 8-C-glycosyl 2,3-Dihydroflavonol (Pinarosa Avato). Molecules 79-92, (2020) ISBN: 978-3-03928-746-8 DOI: 10.3390/books978-3-03928-747-5

Phyllanthus orbicularis (Phyllanthaceae) is an endemic evergreen tropical plant of Cuba that grows in the western part of the island and is used in traditional medicine as an infusion. The aqueous extract of this plant presents a wide range of pharmacological activitiessuch as antimutagenic, antioxidant and antiviral effects. Given the many beneficial effects and the great interest in the development of new pharmacological products from natural sources, the aim of this work was to investigate the phytochemistry of this species and to elucidate the structure of the main bioactive principles. Besides thepresence of several known polyphenols, the major constituent was hitherto not described. The chemical structure of this compound, here named Fideloside, was elucidated by means of HR-ESIMS/MSn, 1D/2D NMR, FT-IR, and ECD as (2R,3R)-(−)-3’,4 ,5,7-tetrahydroxydihydroflavonol-8-C- -D-glucopyranoside. The compound, as well as the plant aqueous preparations, showed promising bioactive properties, i.e., anti-inflammatory capacity in human explanted monocytes, corroborating future pharmacological use for this new natural C-glycosyl flavanonol.
Publikation

Francioso, A.; Franke, K.; Villani, C.; Mosca, L.; d’Erme, M.; Frischbutter, S.; Brandt, W.; Sanchez-Lamar, A.; Wessjohann, L.; Insights into the Phytochemistry of the Cuban Endemic Medicinal Plant Phyllanthus orbicularis: Fideloside, a Novel Bioactive 8-C-glycosyl 2,3-Dihydroflavonol Molecules 24, 2855, (2019) DOI: 10.3390/molecules24152855

Phyllanthus orbicularis (Phyllanthaceae) is an endemic evergreen tropical plant of Cuba that grows in the western part of the island and is used in traditional medicine as an infusion. The aqueous extract of this plant presents a wide range of pharmacological activitiessuch as antimutagenic, antioxidant and antiviral effects. Given the many beneficial effects and the great interest in the development of new pharmacological products from natural sources, the aim of this work was to investigate the phytochemistry of this species and to elucidate the structure of the main bioactive principles. Besides the presence of several known polyphenols, the major constituent was hitherto not described. The chemical structure of this compound, here named Fideloside, was elucidated by means of HR-ESIMS/MSn, 1D/2D NMR, FT-IR, and ECD as (2R,3R)-(−)-3’,4′,5,7-tetrahydroxydihydroflavonol-8-C-β-D-glucopyranoside. The compound, as well as the plant aqueous preparations, showed promising bioactive properties, i.e., anti-inflammatory capacity in human explanted monocytes, corroborating future pharmacological use for this new natural C-glycosyl flavanonol.
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