| | 1 | Author
| StewartA. Brown | Requires cookie* | | | Title
| Biosynthesis of Daphnetin in Daphne mezereum L.  | | | | Abstract
| Shoots of Daphne mezereum synthesized daphnetin (7,8-dihydroxycoumarin) more efficiently from [2-l4C]umbelliferone (7-hydroxycoumarin) than from [2-l4C]p-coumaric acid, and [2-14C]caf-feic acid was more poorly utilized still. These findings do not support the idea of derivation of daphnetin via hydroxylation of the caffeic acid ring at the 2 position, followed by lactone ring formation; instead they are consistent with the concept of daphnetin formation by an additional hydroxylation of umbelliferone at C-8. Umbelliferone was recovered with little l4C dilution from emulsin-hydrolysed extracts of shoots fed labelled umbelliferone, and TLC of extracts from un treated shoots revealed two substances yielding umbelliferone on hydrolysis. Evidence is pre sented from TLC and HPLC analysis that one of these is skimmin (7-O-ß-D-glucosylumbel-liferone), not previously reported from Daphne. The tracer experiments further support the theory that umbelliferone is the general precursor of coumarins bearing two or more hydroxyl functions on the aromatic ring. | | | |
Reference
| Z. Naturforsch. 41c, 247 (1986); received November 4 1985 | | | |
Published
| 1986 | | | |
Keywords
| Biosynthesis, Coumarins, Daphne mezereum, Daphnetin | | | |
Similar Items
| Find | | | DEBUG INFO
| | | | | TEI-XML for
| default:Reihe_C/41/ZNC-1986-41c-0247.pdf | | | | Identifier
| ZNC-1986-41c-0247 | | | | Volume
| 41 | |
| 2 | Author
| M. Aya, IvM. Itova3, MinchoE. Anchevb, StefanG. Panev3, N. Edjalka, V. H. Andjieva3, Sim Eon, S. Popov3 | Requires cookie* | | | Title
| Coumarins and Iridoids from Crucianella graeca, Cruciata glabra, Cruciata laevipes and Cruciata pedemontana (Rubiaceae) | | | | Abstract
| The coumarin and iridoid composition of Crucianella graeca, Cruciata glabra, Cruciata laevipes and Cruciata pedemontana has been studied. Daphnin and daphnetin glucoside do minated in C. glabra along with low concentrations of daphnetin, deacetylasperulosidic acid and scandoside. In C. laevipes and C. pedemontana were found the same coumarin glucosides along with six iridoid glucosides. In Crucianella graeca were found ten iridoid glucosides. | | | |
Reference
| Z. Naturforsch. 51c, 631 (1996); received May 23/July 8 1996 | | | |
Published
| 1996 | | | |
Keywords
| Rubiaceae, Crucianella, Cruciata, Coumarins, Iridoids | | | |
Similar Items
| Find | | | DEBUG INFO
| | | | | TEI-XML for
| default:Reihe_C/51/ZNC-1996-51c-0631.pdf | | | | Identifier
| ZNC-1996-51c-0631 | | | | Volume
| 51 | |
| 3 | Author
| KarinM. Valant-Vetscheraa, Eckhard Wollenweberb | Requires cookie* | | | Title
| Flavonoid Aglycones from the Leaf Surfaces of Some Artemisia spp. (Com positae-Anthem ideae) | | | | Abstract
| Several species of the large genus Artemisia have been analysed for the flavonoid aglycone composition of their leaf exudates. These species belong to different taxonomic groups within Artemisia. Flavone and flavonol aglycones were found as the major flavonoid constituents of the leaf exudates. Many of these compounds were 6-methoxylated, with additional substitu tions at the 7-, 3'-and 4'-position of the molecule. In addition, 7,4'-substituted apigenin and luteolin derivatives and rarely also coumarin derivatives were encountered in some species. The observed substitution trends are in accordance with literature data. Taxonomic and eco logical aspects are briefly discussed. | | | |
Reference
| Z. Naturforsch. 50c, 353—357 (1995); received January 23/February 27 1995 | | | |
Published
| 1995 | | | |
Keywords
| Artemisia, Compositae-Anthemideae, Leaf Exudates, Flavones, Coumarins | | | |
Similar Items
| Find | | | DEBUG INFO
| | | | | TEI-XML for
| default:Reihe_C/50/ZNC-1995-50c-0353.pdf | | | | Identifier
| ZNC-1995-50c-0353 | | | | Volume
| 50 | |
| 4 | Author
| HerbertOliver Kolodziej3, HermanJ. Kayser3, Wim Woerdenbagb, Niesko Van Udenb, Pras | Requires cookie* | | | Title
| Structure -Cytotoxicity Relationships of a Series of Natural and Semi-Synthetic Simple Coumarins as Assessed in Two Human Tumour Cell Lines | | | | Abstract
| The cytotoxicity of 22 natural and semi-synthetic simple coumarins was evaluated in G LC4, a human small cell lung carcinoma cell line, and in CO LO 320. a human colorectal cancer cell line, using the microculture tetrazolium (MTT) assay. With IC 50 values > 100 j.i m , following a continuous (96h) incubation, most coumarins exhibited only low cytotoxicity. Several com pounds, however, displayed significant potencies. As far as the structure -cytotoxicity rela tionship is concerned, it is conspicuous that all the potentially active natural compounds possess at least two phenolic groups in either the 6,7-or 6,8-positions. In addition, the 5-formyl-6-hydroxy substituted semi-synthetic analogue was found to be potent, reflecting the importance of at least two polar functions for high cytotoxicity. | | | |
Reference
| Z. Naturforsch. 52c, 240—244 (1997); received November ll/December 5 1996 | | | |
Published
| 1997 | | | |
Keywords
| Coumarins, Cytotoxicity, Structure-Activity Relationships, Pelargonium sidoides, Geraniaceae | | | |
Similar Items
| Find | | | DEBUG INFO
| | | | | TEI-XML for
| default:Reihe_C/52/ZNC-1997-52c-0240.pdf | | | | Identifier
| ZNC-1997-52c-0240 | | | | Volume
| 52 | |
| 5 | Author
| Oliver Kayser, H. Erbert Kolodziej | Requires cookie* | | | Title
| Antibacterial Activity of Simple Coumarins: Structural Requirements for Biological Activity | | | | Abstract
| The antibacterial activity of a series of simple coumarins was evaluated against 8 microor ganisms, including three Gram-positive (Staphylococcus aureus, beta-hemolytic Streptococcus and Streptococcus pneum oniae) and five Gram-negative bacteria (Escherichia coli, Klebsiella pneum oniae, Pseudom onas aeruginosa, Proteus mirabilis and H aemophilus influenzae), using the microdilution broth method. The coumarins tested showed broad diversity regarding growth inhibitory activity with minimum inhibitory concentrations ranging from 0.9 to >12.4 (j.M . This study, presenting the first systematic analysis of structure-activity relationships among this group of coumarins, revealed some interesting structural requirements. While coumarins with a methoxy function at C-7 and, if present, an OH group at either the C-6 or C-8 position are invariably effective against the spectrum of tested standard bacteria (Gram-negative microorganisms including the Gram-positive bacterium Staphylococcus aureus), the presence of an aromatic dimethoxy arrangement is apparently favourable against those mi croorganisms which require special growth factors (beta-hemolytic Streptococcus, Streptococ cus pneum oniae and Haem ophilus influenzae). A combination of these structural features, two methoxy functions and at least one additional phenolic group as reflected by the highly oxygenated coumarins, identify promising candidates with antibacterial broad-spectrum ac tivity. | | | |
Reference
| Z. Naturforsch. 54c, 169—174 (1999); received November 11/December 8 1998 | | | |
Published
| 1999 | | | |
Keywords
| Coumarins, Antibacterial Activity, Structure-Activity Relationships | | | |
Similar Items
| Find | | | DEBUG INFO
| | | | | TEI-XML for
| default:Reihe_C/54/ZNC-1999-54c-0169.pdf | | | | Identifier
| ZNC-1999-54c-0169 | | | | Volume
| 54 | |
| 6 | Author
| SatishK. Sharma, JinnieM. Garrett, StewartA. Brown | Requires cookie* | | | Title
| Separation of the S-Adenosylmethionine: 5-and 8-Hydroxyfuranocoumarin O-Methyltransferases of Ruta graveolens L. by General Ligand Affinity Chromatography | | | | Abstract
| Two S-adenosyl-L-methionine:furanocoumarin O-methyltransferases of R . graveolens, acting at the 5-and 8-hydroxyls of the psoralen nucleus, were completely resolved by adsorption on a general affinity ligand, 5 -(3-carboxypropanamido) xanthotoxin, followed by specific desorption by bergaptol and xanthotoxol, respectively. The 5-O-methyltransferase was purified 450-fold by this procedure, the 8-O-methyltransferase 112-fold, and both enzyme fractions were electrophoretically homogeneous. No resolution could be achieved of the activity against two 5-hydroxypsoralens or of the activity against two 8-hydroxypsoralens, and conclusive evidence is presented for the existence of only one 5-O-methyltransferase and only one 8-O-methyltransferase acting on linear furanocoumarins. In tro d u c tio n | | | |
Reference
| Z. Naturforsch. 34c, 387 (1979); received March 9 1979 | | | |
Published
| 1979 | | | |
Keywords
| Coumarins, Furanocoumarins, O-Methyltransferases, Affinity Chromatography, R u ta graveolens | | | |
Similar Items
| Find | | | DEBUG INFO
| | | | | TEI-XML for
| default:Reihe_C/34/ZNC-1979-34c-0387.pdf | | | | Identifier
| ZNC-1979-34c-0387 | | | | Volume
| 34 | |
|
