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…
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).
Publikation
Ristok, C.; Leppert, K. N.; Franke, K.; Scherer-Lorenzen, M.; Niklaus, P. A.; Wessjohann, L. A.; Bruelheide, H.;Leaf litter diversity positively affects the decomposition of plant polyphenolsPlant Soil419305-317(2017)DOI: 10.1007/s11104-017-3340-8
Background and AimsLeaf litter decomposition is closely linked to nutrient cycling and driven by environmental conditions, species-specific leaf chemistry, and here in particular by polyphenols composition. However, not much attention has been paid on the decomposition of polyphenols themselves. We hypothesized that phenolics and tannin decomposition rates are species-specific and positively affected by litter species richness.MethodsLeaf litter of three Chinese tree species was exposed to field decomposition conditions, aggregated in mixtures of different species richness (1-, 2-, 3-species mixtures). We sampled litter five times over the course of 171 days, calculated species-specific total phenolics and total protein precipitable tannin decomposition rates, assessed changes in polyphenol composition using HPLC, and tentatively identified compounds by LC-ESI-MS/MS.ResultsLeaf litter richness effects on phenolics and tannin decomposition rates were positive, except for Sapindus-specific tannins, and differed between leaf litter species. Decomposition duration changed polyphenol compositions, and significantly interacted with leaf litter species richness with increasing effects of litter richness with time.ConclusionsLitter diversity effects on polyphenol decomposition are crucial for whole leaf litter decomposition. The contrasting dependencies of phenolics and tannin decomposition rates on leaf litter richness may provide explanations for equivocal results in leaf litter mixture experiments.
Publikation
Anh, N. T. H.; Sung, T. V.; Franke, K.; Wessjohann, L. A.;Phytochemical studies of Rehmannia glutinosa rhizomesPharmazie58593-595(2003)
2,4-Dimethoxy-2-methyl-6H-pyran-3-one (1), a hitherto unknown natural product, and the calcium salt of rehmapicroside (2) have been isolated from rhizomes of the Vietnamese variety of Rehmannia glutinosa Libosch together with a series of known compounds: norcarotenoids (3–5), 2-formyl-5-hydroxymethylfurane (6), the iridoid rehmaglutin D (7), iridoid glycosides (8–12) and phenylethyl alcohol glycosides (13–17). Their structures were determined by mass and NMR spectroscopy.
Publikation
Anh, N. T. H.; Sung, T. V.; Porzel, A.; Franke, K.; Wessjohann, L. A.;Homoisoflavonoids from Ophiopogon japonicus Ker-GawlerPhytochemistry621153-1158(2003)DOI: 10.1016/S0031-9422(02)00515-0
From the ethyl acetate extract of the tuberous roots of Ophiopogon japonicus (Liliaceae) eight known and five new homoisoflavonoidal compounds were isolated. The new compounds are 5,7-dihydroxy-8-methoxy-6-methyl-3-(2′-hydroxy-4′-methoxybenzyl)chroman-4-one (1), 7-hydroxy-5,8-dimethoxy-6-methyl-3-(2′-hydroxy-4′-methoxybenzyl)chroman-4-one (2), 5,7-dihydroxy-6,8-dimethyl-3-(4′-hydroxy-3′-methoxybenzyl)chroman-4-one (3), 2,5,7-trihydroxy-6,8-dimethyl-3-(3′,4′-methylenedioxybenzyl)chroman-4-one (4) and 2,5,7-trihydroxy-6,8-dimethyl-3-(4′-methoxybenzyl)chroman-4-one (5). Their structures have been elucidated by mass and NMR spectroscopy. Compounds 4 and 5 are the first isolated homoisoflavonoids with a hemiacetal function at position 2.Five new and eight known homoisoflavonoids were isolated from the tuberous roots of the medicinal plant Ophiopogon japonicus (Liliaceae) and identified by spectroscopic data.