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
Chalo, D. M.; Kakudidi, E.; Origa-Oryem, H.; Namukobe, J.; Franke, K.; Yenesew, A.; Wessjohann, L. A.;Chemical constituents of the roots of Ormocarpum sennoides subsp. zanzibaricumBiochem. Syst. Ecol.93104142(2020)DOI: 10.1016/j.bse.2020.104142
Phytochemical investigation of the roots of O. sennoides subsp. zanzibaricum Brenan & J.B. Gillett resulted in the isolation of three biflavonoids (trime-chamaejasmin, (+)- chamaejasmin, (+)-liquiritigeninyl-(I-3,II-3)-naringenin), one bi-4-phenyldihydrocoumarin (diphysin), one isoflavan (glabridin), one triterpenoid (3-O-acetyloleanoic acid) and a phytosterol (β-sitosterol). Compounds were identified by detailed MS, 1D and 2D NMR spectroscopic analyses. Their absolute configurations were elucidated based on ECD spectra. The previously undescribed trime-chamaejasmin represents a bis-epi-chamaejasmenin C diastereomer. The chemophenetic significance is discussed in detail. The results contribute to the phytochemical characterization of the genus Ormocarpum and suggest a close chemophenetic relationship with other genera within the subfamily Papilionoideae. Furthermore, this report provides baseline data for comparing the two infraspecific taxa of O. sennoides (Willd.) DC.
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
Tchatchouang Noulala, C. G.; Fotso, G. W.; Rennert, R.; Lenta, B. N.; Sewald, N.; Arnold, N.; Happi, E. N.; Ngadjui, B. T.;Mesomeric form of quaternary indoloquinazoline alkaloid and other constituents from the Cameroonian Rutaceae Araliopsis soyauxii Engl.Biochem. Syst. Ecol.91104050(2020)DOI: 10.1016/j.bse.2020.104050
A mesomeric form of quaternary indoloquinazoline alkaloid, soyauxinium chloride (1) was obtained through the chemical investigation of stem bark and roots of Araliopsis soyauxii Engl. [syn. Vepris soyauxii (Engl.) Mziray] (Rutaceae) together with fifteen known compounds, including three furoquinoline alkaloids, three 2-quinolones, two limonoids, two triterpenes, two steroids, a coumarin, an acridone alkaloid, and a flavonoid glycoside. Their structures were established by comprehensive spectroscopic and spectrometric analyses (1D and 2D NMR, ESI-HR-MS) and by comparison with previously reported data. 13C NMR data of araliopsinine are also reported here for the first time. The isolated compounds were screened in vitro for their effects on the viability of two different human cancer cell lines, namely prostate PC-3 adenocarcinoma cells and colorectal HT-29 adenocarcinoma cells. However, none of the tested compounds exhibited strong anti-proliferative or cytotoxic activities, to either prostate PC-3 cells or colon HT-29 cells. At 100 μM, the furoquinoline maculine showed a slightly increased anti-proliferative effect, however, exclusively on HT-29 cells. The chemotaxonomic significance of the isolated compounds has also been discussed.