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  • 1
    Electronic Resource
    Electronic Resource
    Methyltransferase activity in Allanthm altissima cell suspension cultures (1994)
    Springer
    Plant cell reports 13 (1994), S. 277-281 
    Details
    ISSN: 1432-203X
    Keywords: Alkaloids ; Coumarins ; Methyltransferase
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Enzymes for the methylation of 1hydroxycanthin-6-one and a series of coumarins have been isolated from Ailanthus altissima cell suspension cultures. The coumarin methyltransferases methylate aesculetin to scopoletin and isoscopoletin, but not scopoletin, to scoparone. Fraxetin was methylated to isofraxidine but not to fraxidine and only fraxidine was methylated to 6,7,8-trimethoxycoumarin. These enzymes were studied throughout the culture growth cycle with two cell lines: 1, which produced 1-methoxycanthin-6-one as the major alkaloid and 2, in which canthin-6-one was the major alkaloid.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00233319
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  • 2
    Electronic Resource
    Electronic Resource
    Dietary source for skin alkaloids of poison frogs (Dendrobatidae)? (1994)
    Springer
    Journal of chemical ecology 20 (1994), S. 943-955 
    Details
    ISSN: 1573-1561
    Keywords: Alkaloids ; indolizidines ; pyrrolizidines ; histrionicotoxins ; coccinellines ; dendrobatid frogs ; insects ; millipedes
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology
    Notes: Abstract A wide range of alkaloids, many of which are unknown elsewhere in nature, occur in skin of frogs. Major classes of such alkaloids in dendrobatid frogs are the batrachotoxins, pumiliotoxins, histrionicotoxins, gephyrotoxins, and decahydroquinolines. Such alkaloids are absent in skin of frogs (Dendrobates auratus) raised in Panama on wingless fruit flies in indoor terraria. Raised on leaf-litter arthropods that were collected in a mainland site, such terraria-raised frogs contain tricyclic alkaloids including the beetle alkaloid precoccinelline, 1,4-disubstituted quinolizidines, pyrrolizidine oximes, the millipede alkaloid nitropolyzonamine, a decahydroquinoline, a gephyrotoxin, and histrionicotoxins. The profiles of these alkaloids in the captive-raised frogs are closer to the mainland population ofDendrobates auratus at the leaf-litter site than to the parent population ofDendrobates auratus from a nearby island site. Extracts of a seven-month sampling of leaf-litter insects contained precoccinelline, pyrrolizidine oxime236 (major), and nitropolyzonamine (238). The results indicate a dietary origin for at least some “dendrobatid alkaloids,” in particular the pyrrolizidine oximes, the tricyclic coccinellines, and perhaps the histrionicotoxins and gephyrotoxins.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02059589
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    Paper (German National Licenses)
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  • 3
    Electronic Resource
    Electronic Resource
    A preliminary study of food selection by the orangutan in relation to plant quality (1994)
    Springer
    Primates 35 (1994), S. 255-263 
    Details
    ISSN: 0032-8332
    Keywords: Orangutans ; Pongo pygmaeus ; Diet ; Protein ; Fiber ; Tannins ; Alkaloids
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract We observed the foraging behavior of orangutans in Central Indonesian Borneo during October, November, and December 1980, and analyzed food and nonfood items for water content, neutral detergent fiber, crude protein, available crude protein, and protein:fiber ratio and the presence of alkaloids and tannins. The diet of the orangutan during this season was unusual because it consisted predominantly of seeds and unripe, rather than ripe, fruits. Also, the major diet item, the seeds ofIrvingia malayana, had been ignored in previous years when it had fruited. In leaves, protein content was more closely associated with food choice than either neutral detergent fiber or the protein:fiber ratio. Flowers had the highest protein content and protein:fiber ratio of any food item. Tannins were found in most food items, but the presence of alkaloids was found in only one.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02382723
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  • 4
    Electronic Resource
    Electronic Resource
    Partial Synthesis of Nitrogenous Brassinosteroid Analogues with 22,26-Epiminocholestane and Spirosolane Skeleton (1994)
    Weinheim : Wiley-Blackwell
    Liebigs Annalen 1994 (1994), S. 1143-1147 
    Details
    ISSN: 0170-2041
    Keywords: Bassinosteroids ; Steroids ; Alkaloids ; Solasodine ; Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Starting with the known (22S,25R)-16β-acetoxy-N-acetyl-22,26-epiminocholest-5-en-3β-ol (4), which has been prepared from the Solanum steroid alkaloid solasodine (3), we synthesized the nitrogenous brassinosteroid analogues (22S,25R)-2α,3α,16β-trihydroxy-22,26-epimino-5α-cholestan-6-one (11), (25R)-2α,22α-dihydroxy-5α,22αN-spirosolan-6-one (13), (22S,25R)-2α,3α,16β-trihydroxy-22,26-epimino-6,7-seco-5α-cholestano-6,7-lactone (15), and (25R)-2α-3α-dihydroxy-6,7-seco-5α,22αN-spirosolano-6,7-lactone (18) as well as some of their derivatives.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/jlac.199419941115
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  • 5
    Electronic Resource
    Electronic Resource
    Ein einfacher Zugang zu den tetracyclischen Vorläufern der Hetero- und Secoyohimbane, Strychnos- und Oxindolalkaloide (1994)
    Weinheim : Wiley-Blackwell
    Liebigs Annalen 1994 (1994), S. 151-158 
    Details
    ISSN: 0170-2041
    Keywords: Indoles ; Alkaloids ; Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: A Simple Entry into the Series of Tetracyclic Hetero- and Secoyohimbanes, Strychnos and Oxindole AlkaloidsThe divinylogous urethane 4a reacts in diluted acetic acid to give the indolochinolizine 9 (yield 40%). The total amount grows up to 65%, if compound 14, prepared from 4a in nearly quantitative yield, is allowed to react with trifluoroacetic acid for a few minutes. Similarily, 4b and 4c give by treatment with SnCl2 and heat in an [4+2]-cycloaddition reaction the spiroindolines 17 and 18. Oxytryptamine reacts with 2 moles of 2 to give immediately the spirooxindole 21. This compound can be rearranged to give 23 (after treatment with acid, reduction and catalytic hydrogenation). 23 has the cis-configuration of rhyncophylline.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/jlac.199419940208
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    Paper (German National Licenses)
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