Geschmack ist vorhersagbar: Mit FlavorMiner. FlavorMiner heißt das Tool, das IPB-Chemiker und Partner aus Kolumbien jüngst entwickelt haben. Das Programm kann, basierend auf maschinellem Lernen (KI), anhand der…
Seit Februar 2021 bietet Wolfgang Brandt, ehemaliger Leiter der Arbeitsgruppe Computerchemie am IPB, sein Citizen Science-Projekt zur Pilzbestimmung an. Dafür hat er in regelmäßigen Abständen öffentliche Vorträge zur Vielfalt…
de Moura, P. H. B.; de Sousa, A. A.; Porzel, A.; Wessjohann, L. A.; Leal, I. C. R.; Martins, R. C. C.;Characterization of antibacterial proanthocyanidins of Dalbergia monetaria, an amazonian medicinal plant, by UHPLC-HRMS/MSPlanta Med.86858– 866(2020)DOI: 10.1055/a-1170-8016
Dalbergia monetaria is an Amazonian plant whose bark is widely used to treat urinary tract infections. This paper describes a bio-guided study of ethanolic extracts from the bark and leaves of D. monetaria, in a search for metabolites active against human pathogenic bacteria. In vitro assays were performed against 10 bacterial strains, highlighting methicillin-sensitive Staphylococcus aureus and methicillin-resistant Staphylococcus aureus and Pseudomonas aeruginosa. Fractioning of the extracts was performed using instrumental and classical techniques, and samples were characterized by UHPLC-HRMS/MS. Ethyl acetate fractions from bark and leaves showed similar antibacterial activities. EAFB is enriched in isoflavone C-glucosides and EAFL enriched in proanthocyanidins. Subfractions from EAFL presented higher activity and showed a complex profile of proanthocyanidins constructed by (epi)-cassiaflavan and (epi)-catechin units, including dimers, trimers and tetramers. The fragmentation pattern emphasized the neutral loss of cassiaflavan units by quinone-methide fission. Fraction SL7-6, constituted by (ent)-cassiaflavan-(ent)-cassiaflavan-(epi)-catechin isomers, showed the lowest MIC against the S. aureus and P. aeruginosa with values corresponding to 64 and 32 µg/mL, respectively. Cassiaflavan-proanthocyanidins have not been found previously in another botanical genus, except in Cassia, and the traditional medicinal use of D. monetaria might be related to the antibacterial activity of proanthocyanidins characterized in the species.
Publikation
Jouda, J.-B.; Njoya, E. M.; Fobofou, S. A. T.; Zhou, Z. Y.; Qiang, Z.; Mbazoa, C. D.; Brandt, W.; Zhang, G.-l.; Wandji, J.; Wang, F.;Natural Polyketides Isolated from the Endophytic Fungus
Phomopsis sp. CAM212 with a Semisynthetic Derivative Downregulating
the ERK/IκBα Signaling PathwaysPlanta Med.861032-1042(2020)DOI: 10.1055/a-1212-2930
AbstractThree previously undescribed natural products, phomopsinin A – C
(1 – 3), together with three known compounds, namely,
cis-hydroxymellein (4), phomoxanthone A (5) and
cytochalasin L-696,474 (6), were isolated from the solid culture of
Phomopsis sp. CAM212, an endophytic fungus obtained from Garcinia
xanthochymus. Their structures were determined on the basis of
spectroscopic data, including IR, NMR, and MS. The absolute configurations of
1 and 2 were assigned by comparing their experimental and
calculated ECD spectra. Acetylation of compound 1 yielded 1a, a
new natural product derivative that was tested together with other isolated
compounds on lipopolysaccharide-stimulated RAW 264.7 cells. Cytochalasin
L-696,474 (6) was found to significantly inhibit nitric oxide production,
but was highly cytotoxic to the treated cells, whereas compound 1
slightly inhibited nitric oxide production, which was not significantly
different compared to lipopolysaccharide-treated cells. Remarkably, the
acetylated derivative of 1, compound 1a, significantly inhibited
nitric oxide production with an IC50 value of 14.8 µM and no
cytotoxic effect on treated cells, thereby showing the importance of the acetyl
group in the anti-inflammatory activity of 1a. The study of the mechanism
of action revealed that 1a decreases the expression of inducible nitric
oxide synthase, cyclooxygenase 2, and proinflammatory cytokine IL-6 without an
effect on IL-1β expression. Moreover, it was found that 1a exerts
its anti-inflammatory activity in lipopolysaccharide-stimulated RAW 264.7
macrophage cells by downregulating the activation of ERK1/2 and by preventing
the translocation of nuclear factor κB. Thus, derivatives of phomopsinin
A (1), such as compound 1a, could provide new anti-inflammatory
leads.
Publikation
Jablonická, V.; Ziegler, J.; Vatehová, Z.; Lišková, D.; Heilmann, I.; Obložinský, M.; Heilmann, M.;Inhibition of phospholipases influences the metabolism of wound-induced benzylisoquinoline alkaloids in Papaver somniferum L.J. Plant Physiol.2231-8(2018)DOI: 10.1016/j.jplph.2018.01.007
Benzylisoquinoline alkaloids (BIAs) are important secondary plant metabolites and include medicinally relevant drugs, such as morphine or codeine. As the de novo synthesis of BIA backbones is (still) unfeasible, to date the opium poppy plant Papaver somniferum L. represents the main source of BIAs. The formation of BIAs is induced in poppy plants by stress conditions, such as wounding or salt treatment; however, the details about regulatory processes controlling BIA formation in opium poppy are not well studied. Environmental stresses, such as wounding or salinization, are transduced in plants by phospholipid-based signaling pathways, which involve different classes of phospholipases. Here we investigate whether pharmacological inhibition of phospholipase A2 (PLA2, inhibited by aristolochic acid (AA)) or phospholipase D (PLD; inhibited by 5-fluoro-2-indolyl des-chlorohalopemide (FIPI)) in poppy plants influences wound-induced BIA accumulation and the expression of key biosynthetic genes. We show that inhibition of PLA2 results in increased morphinan biosynthesis concomitant with reduced production of BIAs of the papaverine branch, whereas inhibition of PLD results in increased production of BIAs of the noscapine branch. The data suggest that phospholipid-dependent signaling pathways contribute to the activation of morphine biosynthesis at the expense of the production of other BIAs in poppy plants. A better understanding of the effectors and the principles of regulation of alkaloid biosynthesis might be the basis for the future genetic modification of opium poppy to optimize BIA production.
Publikation
Frolov, A.; Bilova, T.; Paudel, G.; Berger, R.; Balcke, G. U.; Birkemeyer, C.; Wessjohann, L. A.;Early responses of mature Arabidopsis thaliana plants to reduced water potential in the agar-based polyethylene glycol infusion drought modelJ. Plant Physiol.20870-83(2017)DOI: 10.1016/j.jplph.2016.09.013
Drought is one of the most important environmental stressors resulting in increasing losses of crop plant productivity all over the world. Therefore, development of new approaches to increase the stress tolerance of crop plants is strongly desired. This requires precise and adequate modeling of drought stress. As this type of stress manifests itself as a steady decrease in the substrate water potential (ψw), agar plates infused with polyethylene glycol (PEG) are the perfect experimental tool: they are easy in preparation and provide a constantly reduced ψw, which is not possible in soil models. However, currently, this model is applicable only to seedlings and cannot be used for evaluation of stress responses in mature plants, which are obviously the most appropriate objects for drought tolerance research. To overcome this limitation, here we introduce a PEG-based agar infusion model suitable for 6–8-week-old A. thaliana plants, and characterize, to the best of our knowledge for the first time, the early drought stress responses of adult plants grown on PEG-infused agar. We describe essential alterations in the primary metabolome (sugars and related compounds, amino acids and polyamines) accompanied by qualitative and quantitative changes in protein patterns: up to 87 unique stress-related proteins were annotated under drought stress conditions, whereas further 84 proteins showed a change in abundance. The obtained proteome patterns differed slightly from those reported for seedlings and soil-based models.