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Publications
The following lichen substances were detected in six species of Physciaceae by HPLC-ESI-MS/MS: Phaeophyscia orbicularis: atranorin (1), methyl ß-orcinolcarboxylate (6), Physcia adscendens: 1, 6, chloroatranorin (2), 5-hydroxyatranorin (3, new), norbaeomycesic acid (4), 3'-demethylatranorin (5, new), Physcia aipolia: 1, 2, 3, 4, 5 and 6, Physcia caesia: 1, 4 and 5, Physcia stellaris: 1, 2, 4, 5 and 6, Physcia tenella: 1, 2, 4, 5 and 6.
Publications
From yellow petals of Iceland poppy, besides the known flavonoid gossypitrin, seven kaempferol derivatives were isolated. In addition to kaempferol 3-O-β-sophoroside and kaempferol 3-O-β-sophoroside-7-O-β-glucoside, known from other plants, the mono- and dimalonyl conjugates of the latter were identified by MS and NMR spectroscopy. Structure analyses of a set of co-occurring pigments, the nudicaulins, revealed that they have the identical acylated glycoside moieties attached to a pentacyclic indole alkaloid skeleton for which the structure of 19-(4-hydroxyphenyl)-10H-1,10-ethenochromeno[2,3-b]indole-6,8,18-triol was deduced from MS and NMR as well as chemical and chiroptical methods.
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Colonization of roots of Ornithogalum umbellatum by the arbuscular mycorrhizal fungus Glomus intraradices induced the accumulation of different types of apocarotenoids. In addition to the mycorrhiza-specific occurrence of cyclohexenone derivatives and the “yellow pigment” described earlier, free mycorradicin and numerous mycorradicin derivatives were detected in a complex apocarotenoid mixture for the first time. From the accumulation pattern of the mycorradicin derivatives their possible integration into the continuously accumulating “yellow pigment” is suggested. Structure analyses of the cyclohexenone derivatives by MS and NMR revealed that they are mono-, di- and branched triglycosides of blumenol C, 13-hydroxyblumenol C, and 13-nor-5-carboxy-blumenol C, some of which contain terminal rhamnose as sugar moiety.
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O-Peracetylated N-(β-d-glucopyranosyl)imino trimethylphosphorane obtained in situ from 2,3,4,6-tetra-O-acetyl-β-d-glucopyranosyl azide and PMe3 was reacted with saturated and unsaturated aliphatic and aromatic dicarboxylic acids, or their anhydrides, or monoesters to give the corresponding N-(β-d-glucopyranosyl) monoamides of dicarboxylic acids or derivatives. The acetyl protecting groups were removed according to the Zemplén protocol to give a series of compounds which showed moderate inhibitory effects against rabbit muscle glycogen phosphorylase b. The best inhibitor was 3-(N-β-d-glucopyranosyl-carbamoyl)propanoic acid (7) with Ki = 20 μM.
Publications
The aquatic hyphomycete Heliscus lugdunensis belongs to a group of exclusively aquatic mitosporic fungi with an only scarcely explored potential to oxidatively attack xenobiotic compounds, and was used to study the biotransformation of the environmental pollutant metabolite 1-naphthol. H. lugdunensis metabolized approximately 74% of 1-naphthol within 5 days. The identification and quantification of degradation products using gas chromatography-mass spectrometry, liquid chromatography-mass spectrometry, and high performance liquid chromatography revealed that approximately 12% of the parent compound was converted into 1-naphthylsulfate, 3% was transformed into 1-methoxy-naphthalene, and less than 1% was converted into 1,4-naphthoquinone. A further metabolite, most likely 4-hydroxy-1-naphthylsulfate, was also detected. In contrast to sulfate conjugate metabolites, no glucuronide and glucoside conjugates of 1-naphthol were found, and neither UDP-glucuronyltransferase nor UDP-glucosyltransferase present in H. lugdunensis showed activity towards 1-naphthol. These results support a role of fungi adapted to aquatic environments in affecting the environmental fate of pollutants in aquatic ecosystems.
Publications
In the present study morphinan, tetrahydrobenzylisoquinoline, benzo[c]phenanthridine, and phthalideisoquinoline alkaloids were determined qualitatively and quantitatively by HPLC and LC-MS analysis in tissues of the Tasmanian Papaver somniferum L. elite cultivar C048-6-14-64. The data were compared with the results from the low-morphine cultivar “Marianne”. In the elite cultivar, 91.2% of the latex alkaloids consist of the three pharmaceutically most valuable alkaloids: morphine, codeine, and thebaine. In the root system, the major alkaloids are sanguinarine/10-hydroxysanguinarine and dihydrosanguinarine/10-hydroxydihydrosanguinarine. In the stems and leaves of C048-6-14-64, the same alkaloids were measured as in the latex. In the stems, a gradient in relative total alkaloid content from the top downward toward the roots was observed. The concentration of morphine was decreasing toward the roots, whereas an increasing gradient from the upper to the lower stem parts was detected for codeine. The relative total alkaloid concentration in leaves remained constant; no gradient was observed. The cultivar “Marianne” displayed a shifted pattern of alkaloid accumulation and reduced levels of total alkaloid. In the condiment cultivar, 80.5% of the alkaloids of the latex consisted of the two phthalideisoquinoline alkaloids narcotoline and noscapine. Only 18.8% of the relative total alkaloid content were morphinan alkaloids. In contrast to the narcotic cultivar, in which the benzo[c]phenanthridines in roots dominated over the morphinan and tetrahydrobenzylisoquinoline alkaloids, the concentration of benzo[c]phenanthridines in “Marianne” was similar to that of morphinan and tetrahydrobenzylisoquinoline alkaloids. These data suggest a differential alkaloid regulation in each cultivar of P. somniferum.
Publications
Members of the Brassicaceae accumulate complex patterns of sinapate esters, as shown in this communication with seeds of oilseed rape (Brassica napus). Fifteen seed constituents were isolated and identified by a combination of high-field NMR spectroscopy and high resolution electrospray ionisation mass spectrometry. These include glucose, gentiobiose and kaempferol glycoside esters as well as sinapine (sinapoylcholine), sinapoylmalate and an unusual cyclic spermidine amide. One of the glucose esters (1,6-di-O-sinapoylglucose), two gentiobiose esters (1-O-caffeoylgentiobiose and 1,2,6′-tri-O-sinapoylgentiobiose) and two kaempferol conjugates [4′-(6-O-sinapoylglucoside)-3,7-di-O-glucoside and 3-O-sophoroside-7-O-(2-O-sinapoylglucoside)] seem to be new plant products. Serine carboxypeptidase-like (SCPL) acyltransferases catalyze the formation of sinapine and sinapoylmalate accepting 1-O-β-acetal esters (1-O-β-glucose esters) as acyl donors. To address the question whether the formation of other components of the complex pattern of the sinapate esters in B. napus seeds is catalyzed via 1-O-sinapoyl-β-glucose, we performed a seed-specific dsRNAi-based suppression of the sinapate glucosyltransferase gene (BnSGT1) expression. In seeds of BnSGT1-suppressing plants the amount of sinapoylglucose decreased below the HPLC detection limit resulting in turn in the disappearance or marked decrease of all the other sinapate esters, indicating that formation of the complex pattern of these esters in B. napus seeds is dependent on sinapoylglucose. This gives rise to the assumption that enzymes of an SCPL acyltransferase family catalyze the appropriate transfer reactions to synthesize the accumulating esters.
Publications
Two new amide-linked conjugates of jasmonic acid, N-[(3R,7R)-(−)-jasmonoyl]-(S)-dopa (3) and N-[(3R,7R)-(−)-jasmonoyl]-dopamine (5), were isolated in addition to the known compound N-[(3R,7R)-(−)-jasmonoyl]-(S)-tyrosine (2) from the methanolic extract of flowers of broad bean (Vicia faba). Their structures were proposed on the basis of spectroscopic data (LC-MS/MS) and chromatographic properties on reversed and chiral phases and confirmed by partial syntheses. Furthermore, tyrosine conjugates of two cucurbic acid isomers (7, 8) were detected and characterized by LC-MS. Crude enzyme preparations from flowers of V. faba hydroxylated both (±)-2 and N-[(3R,7R/3S,7S)-(−)-jasmonoyl]tyramine [(±)-4] to (±)-3 and (±)-5, respectively, suggesting a possible biosynthetic relationship. In addition, a commercial tyrosinase (mushroom) and a tyrosinase-containing extract from hairy roots of red beet exhibited the same catalytic properties, but with different substrate specificities. The conjugates (±)-2, (±)-3, (±)-4, and (±)-5 exhibited in a bioassay low activity to elicit alkaloid formation in comparison to free (±)-jasmonic acid [(±)-1].