Unser 10. Leibniz Plant Biochemistry Symposium am 7. und 8. Mai war ein großer Erfolg. Thematisch ging es in diesem Jahr um neue Methoden und Forschungsansätze der Naturstoffchemie. Die exzellenten Vorträge über Wirkstoffe…
Omanische Heilpflanze im Fokus der Phytochemie IPB-Wissenschaftler und Partner aus Dhofar haben jüngst die omanische Heilpflanze Terminalia dhofarica unter die phytochemische Lupe genommen. Die Pflanze ist reich an…
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…
Noleto‐Dias, C.; Farag, M. A.; Porzel, A.; Tavares, J. F.; Wessjohann, L. A.;A multiplex approach of MS, 1D‐, and 2D‐NMR metabolomics in plant ontogeny: A case study on Clusia minor L. organs (leaf, flower, fruit, and seed)Phytochem. Anal.35445-468(2024)DOI: 10.1002/pca.3300
Introduction: The genus Clusia L. is mostly recognised for the production of prenylated benzophenones and tocotrienol derivatives.Objectives: The objective of this study was to map metabolome variation within Clusia minor organs at different developmental stages.Material and Methods: In total 15 organs/stages (leaf, flower, fruit, and seed) were analysed by UPLC‐MS and 1H‐ and heteronuclear multiple‐bond correlation (HMBC)‐NMR‐based metabolomics.Results: This work led to the assignment of 46 metabolites, belonging to organic acids(1), sugars(2) phenolic acids(1), flavonoids(3) prenylated xanthones(1) benzophenones(4) and tocotrienols(2). Multivariate data analyses explained the variability and classification of samples, highlighting chemical markers that discriminate each organ/stage. Leaves were found to be rich in 5‐hydroxy‐8‐methyltocotrienol (8.5 μg/mg f.w.), while flowers were abundant in the polyprenylated benzophenone nemorosone with maximum level detected in the fully mature flower bud (43 μg/mg f.w.). Nemorosone and 5‐hydroxy tocotrienoloic acid were isolated from FL6 for full structural characterisation. This is the first report of the NMR assignments of 5‐hydroxy tocotrienoloic acid, and its maximum level was detected in the mature fruit at 50 μg/mg f.w. Seeds as typical storage organ were rich in sugars and omega‐6 fatty acids.Conclusion: To the best of our knowledge, this is the first report on a comparative 1D‐/2D‐NMR approach to assess compositional differences in ontogeny studies compared with LC‐MS exemplified by Clusia organs. Results derived from this study provide better understanding of the stages at which maximal production of natural compounds occur and elucidate in which developmental stages the enzymes responsible for the production of such metabolites are preferentially expressed.
Publikation
Hashemi Haeri, H.; Schneegans, N.; Eisenschmidt-Bönn, D.; Brandt, W.; Wittstock, U.; Hinderberger, D.;Characterization of the active site in the thiocyanate-forming protein from Thlaspi arvense (TaTFP) using EPR spectroscopyBiol. Chem.405105-118(2024)DOI: 10.1515/hsz-2023-0187
Glucosinolates are plant thioglucosides, which act as chemical defenses. Upon tissue damage, their myrosinase-catalyzed hydrolysis yields aglucones that rearrange to toxic isothiocyanates. Specifier proteins such as thiocyanate-forming protein from Thlaspi arvense (TaTFP) are non-heme iron proteins, which capture the aglucone to form alternative products, e.g. nitriles or thiocyanates. To resolve the electronic state of the bound iron cofactor in TaTFP, we applied continuous wave electron paramagnetic resonance (CW EPR) spectroscopy at X-and Q-band frequencies (∼9.4 and ∼34 GHz). We found characteristic features of high spin and low spin states of a d5 electronic configuration and local rhombic symmetry during catalysis. We monitored the oxidation states of bound iron during conversion of allylglucosinolate by myrosinase and TaTFP in presence and absence of supplemented Fe2+. Without added Fe2+, most high spin features of bound Fe3+ were preserved, while different g’-values of the low spin part indicated slight rearrangements in the coordination sphere and/or structural geometry. We also examined involvement of the redox pair Fe3+/Fe2 in samples with supplemented Fe2+. The absence of any EPR signal related to Fe3+ or Fe2+ using an iron-binding deficient TaTFP variant allowed us to conclude that recorded EPR signals originated from the bound iron cofactor.
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 joazeiroNat. Prod. Commun.161-13(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
Anh, N. T. H.; Tuan, N. V.; Thien, D. D.; Quan, T. D.; Tam, N. T.; Lien, G. T. K.; Franke, K.; Thuy, T. T.; Sung, T. V.;Chemical Constituents of Chirita drakeiNat. Prod. Commun.12563-566(2017)DOI: 10.1177/1934578X1701200425
Chirita drakei Burtt (now accepted as Primulina drakei (B.L.Burtt) Mich.Möller & A.Weber) is growing on limestone mountain slopes of Ha Long Bay islands in Vietnam. The chemical investigation of the aerial parts of C. drakei led to the isolation and structural elucidation of two new compounds named chiridrakoside A (1) and chiridrakoside B (2) besides twelve known compounds comprising five phenylethanoid glycosides (3–7), two lignans (8, 9), a phenyl propanoid (10), an anthraquinone (11), a furan derivative (12) and two triterpenes (13, 14). All described compounds, except 4, 5 and 11, were obtained for the first time from the genera Chirita or Primulina. The cytotoxic activity of the isolated compounds was evaluated against the four human cancer cell lines KB (mouth epidermal carcinoma), HepG2 (hepatocellular carcinoma), Lu (lung carcinoma) and MCF7 (breast carcinoma). Epoxyconiferyl alcohol (10) exhibited cytotoxic activity against the tested cell lines (IC50 from 46 to 128 μM).