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…
Winter, J.; Schneider, B.; Strack, D.; Adam, G.;Role of a cytochrome P450-dependent monooxygenase in the hydroxylation of 24-epi-brassinolidePhytochemistry45233-237(1997)DOI: 10.1016/S0031-9422(96)00827-8
24-epi-Brassinolide, exogenously applied to cell suspension cultures of Lycopersicon esculentum is hydroxylated at C-25 and C-26, respectively, followed by glucosylation of the newly formed hydroxyl group. Treatment of the cell cultures with the specific cytochrome P450 inhibitors, clotrimazole and ketoconazole, resulted in a strong decrease of only the C-25 hydroxylation, whereas hydroxylation at C-26 was not affected. The common cytochrome P450 inducers, ethanol, MnCl2, phenobarbital, pregnenolone 16α-carbonitrile or clofibrate, did not induce hydroxylation activity at C-25 or at C-26. In addition, substrate analogues (22S,23S-homobrassinolide, 24-epi-castasterone, ecdysone, and 20-OH-ecdysone) were not accepted. Only application of 24-epi-brassinolide and brassinolide resulted in an increased activity of both the C-25- and C-26-hydroxylases. For further examination of the molecular level of this inducing effect, the influence of the protein biosynthesis inhibitor cycloheximide has been studied. Thus, increase of both hydroxylase activities is obviously based on gene expression by action of the substrates, 24-epi-brassinolide and brassinolide.
Publikation
Ripperger, H.; Porzel, A.;Steroidal alkaloid glycosides from Solanum suaveolensPhytochemistry461279-1282(1997)DOI: 10.1016/S0031-9422(97)80027-1
In addition to khasianine, solamargine, xylosylsolamargine and solasonine, three steroidal alkaloid glycosides, solasuaveoline, dihydrosolasuaveoline and isosolasuaveoline, have been isolated from aerial parts of Solanum suaveolens. The structures have been assigned by NMR investigations as (25R)-3β-{O-β-d-glucopyranosyl-(1 → 2)-O-β-d-glucopyranosyl-(1 → 4)-[O-α-l-rhamnopyranosyl-(1 → 2)]-β-d-galactopyranosyloxy}-22αN-spirosol-5-ene, (25R)-3β-{O-β-d-glucopyranosyl-(1 → 2)-O-β-d-glucopyranosyl-(1 → 4)-[O-α-l-rhamnopyranosyl-(1 → 2)]-β-d-galactopyranosyloxy}-5α,22αN-spirosolane and (25R)-3β-{O-β-d-glucopyranosyl-(1 → 6)-O-β-d-glucopyranosyl-(1 → 3)-[O-α-l-rhamnopyranosyl-(1 → 2)]-β-d-galactopyranosyloxy}-22αN-spirosol-5-ene, respectively.
Publikation
Rhenius, M.; Porzel, A.; Diettrich, B.; Luckner, M.;21′-di-dehydro-deacetyllanatoside C, a biotransformation product of deacetyllanatoside C from senescent shoot cultures of Digitalis lanataPhytochemistry441061-1064(1997)DOI: 10.1016/S0031-9422(96)00676-0
Feeding deacetyllanatoside C to senescent shoot cultures of Digitalis lanata resulted in the formation of a new product, which was isolated by semi-preparative HPLC. The molecular structure was elucidated by means of HPLC-mass spectrometry and NMR as 21′-di-dehydro-deacetyllanatoside C.
Publikation
Peipp, H.; Maier, W.; Schmidt, J.; Wray, V.; Strack, D.;Arbuscular mycorrhizal fungus-induced changes in the accumulation of secondary compounds in barley rootsPhytochemistry44581-587(1997)DOI: 10.1016/S0031-9422(96)00561-4
Hordeum vulgare (barley) was grown in a defined nutritional medium with and without the arbuscular mycorrhizal fungus Glomus intraradices. HPLC of methanolic extracts from the roots of mycorrhized and non-mycorrhized plants revealed fungus-induced accumulation of some secondary metabolites. These compounds were isolated and identified by spectroscopic methods (NMR, MS) to be the hydroxycinnamic acid amides N-(E)-4-coumaroylputrescine, N-(E)-feruloylputrescine, N-(E)-4-coumaroylagmatine and N-(E)-feruloylagmatine, exhibiting a transient accumulation, and the cyclohexenone derivatives 4-(3-O-β-glucopyranosyl-butyl)-3-(hydroxymethyl)-5,5-dimethyl-2-cyclohexen-1-one and 4-{3-O-[(2′-O-β-glucuronosyl)-β-glucopyranosyl]-butyl}-3,5,5-trimethyl-2-cyclohexen-1-one (blumenin), exhibiting a continuous accumulation. A third cyclohexenone derivative, 4-{3-O-[(2′-O-β-glucuronosyl)-β-glucopyranosyl]-1-butenyl}-3,5,5-trimethyl-2-cyclohexen-1-one, was detectable only in minute amounts. It is suggested that accumulation of the amides in early developmental stages of barley mycorrhization reflects initiation of a defence response. However, the continuous accumulation of the cyclohexenone derivatives, especially blumenin, seems to correlate with the establishment of a functional barley mycorrhiza.