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  • 1
    Electronic Resource
    Electronic Resource
    Dietary cancer risk conditional cancerogens in produce of livestock fed on species of spurge (Euphorbiaceae) (1998)
    Springer
    Journal of cancer research and clinical oncology 124 (1998), S. 131-140 
    Details
    ISSN: 1432-1335
    Keywords: Key words Conditional cancerogens ; Diterpene esters ; Euphorbia peplus ; Food chain ; Dietary cancer ; Milk polluted ; Skin irritants ; Tumor promoters
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract The hypothesis was proposed that there is a risk of dietary cancer from conditional cancerogens in produce of livestock polluted with irritants of the diterpene ester type, picked up by feeding on species of Euphorbiaceae ( spurge). To challenge this, several herbaceous plants of the genus Euphorbia, widespread as weeds and contaminants of livestock fodder, were identified botanically and extracts of their aerial parts were tested for irritancy on the mouse ear. As compared to a standard probe of croton oil, the extracts of E.␣peplus, E. nubica and E. helioscopia displayed irritancy. The most active extract (that from E. peplus) was investigated by a fractionation procedure monitored by the mouse ear assay, and five molecularly uniform irritant Euphorbia factors Pe1–Pe5 were identified as diterpene ester-type toxins. Together these factors comprise at least 11 ppm in the aerial parts. They were characterized individually to␣carry the diterpene parent alcohols ingenol, 20-deoxyingenol, and 20-deoxyingenol-6 α, 7α-epoxide. The irritancy of the aerial plant parts was shown to be caused mainly by the Euphorbia factors Pe1 and Pe2 together. Upon chronic administration of these irritants and hyperplasiogens as principal cancerogenic risk factors in the mouse skin initiation/promotion bioassay, Pe1 and Pe2 were established as tumor promoters. These findings together support the␣initial hypothesis and suggest the need for further investigations to determine whether there is a consequent risk of dietary cancer.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s004320050146
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  • 2
    Electronic Resource
    Electronic Resource
    Dietary cancer risk from conditional cancerogens in produce of livestock fed on species of spurge (Euphorbiaceae) (1998)
    Springer
    Journal of cancer research and clinical oncology 124 (1998), S. 179-185 
    Details
    ISSN: 1432-1335
    Keywords: Key words Conditional cancerogens ; Risk of dietary cancer ; Diterpene esters ; Euphorbia peplus ; Food chain ; Lactating goats ; Polluted milk ; Poisoning by contaminated fodder ; Tumour promoters
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract Lactating goats were fed on aerial parts of the herb Euphorbia peplus L. admixed with their usual green fodder. During the experimental feeding period they showed symptoms of general poisoning. In necropsy the main toxic effects were seen in the heart, lung and liver. Histopathological examinations revealed that the primary toxic effects originated from degenerative changes in parenchymal and endothelial cells. Adverse symptoms in the liver and kidney were also reflected in an alteration of the levels of certain serum enzymes and of blood urea nitrogen. The milk of the goats fed on E. peplus, consumed by their young kids, caused poisoning and even death, with signs similar to those observed in the adult dams. These observations support the hypothesis that the poisoning observed in both milk-raised kids and mother goats is caused by diterpene ester type toxins present in the aerial parts of the herb contaminating the dams fodder. Generally, such skin irritant and hyperplasiogenic toxins are known to be highly active tumour promoters of skin and other organ, e.g. in mice. Lactating goats – as an important source of milk around the world – in a setting similar to that described, may provide a valid experimental etiological model for investigation of food polluted by tumour-promoting diterpene ester toxins.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s004320050152
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  • 3
    Electronic Resource
    Electronic Resource
    Dietary cancer risk from conditional cancerogens in produce of livestock fed on species of spurge (Euphorbiaceae) (1998)
    Springer
    Journal of cancer research and clinical oncology 124 (1998), S. 301-306 
    Details
    ISSN: 1432-1335
    Keywords: Key words Conditional cancerogens ; Diterpene esters ; Euphorbia factors ; Food chain ; Metabolism of␣tumor promoters in goats ; Poisoning by contaminated fodder ; Pollution of goat's milk
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract Special procedures were developed to investigate poisonous milk of lactating goats fed experimentally on aerial parts of the herb Euphorbia peplus L. In extracts of the milk, weakly irritant in the mouse-ear assay, three diterpene ester toxins were detected by techniques of high-performance liquid chromatography. They are of the ingenane structural type: Euphorbia␣factor Pel (ingenol 20-acetate 3-angelate), Euphorbia factor Pe2 (20-deoxyingenol 3-angelate) and Euphorbia factor␣Pe4 (20-deoxyingenol-6α,7α-epoxide 3-angelate). From goats milk collected 15 days after cessation of the experimental feeding period, extracts were completely free of diterpene ester toxins. The toxins polluting the milk are identical to diterpene ester entities occurring in the aerial parts of E. peplus. Of these, Euphorbia factors Pe1 and Pe2 are known as promoters of tumors of mouse skin. Apart from the toxic Euphorbia factors, the non-toxic parent alcohol ingenol was also detected in the milk. It is absent in the plant, and may have been generated metabolically from a certain portion of the toxic diterpene esters picked up by the goats from their fodder. The results presented here provide, for the first time, data for a novel interpretation of the locally high incidence of esophageal cancer observed in certain areas in the Caspian littoral of Iran, associated with a greater consumption of goat's (and sheep's) milk.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s004320050173
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  • 4
    Electronic Resource
    Electronic Resource
    Über das toxische, entzündliche und cocarcinogene Prinzip des Crotonöls (1962)
    Weinheim : Wiley-Blackwell
    Zeitschrift für die chemische Industrie 74 (1962), S. 722-723 
    Details
    ISSN: 0044-8249
    Keywords: Chemistry ; General Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/ange.19620741812
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  • 5
    Electronic Resource
    Electronic Resource
    Zur Chemie des Phorbols, III. Mono- und Diacetate des Phorbols (1967)
    Weinheim : Wiley-Blackwell
    Liebigs Annalen 705 (1967), S. 199-210 
    Details
    ISSN: 0075-4617
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Drei der fünf Hydroxylgruppen des Phorbols lassen sich mit Acetanhydrid in Pyridin verestern. Mit einem Unterschuß von Acetanhydrid entstehen neben Phorbol-triacetat die drei möglichen Diacetate und zwei Monoacetate, die sich durch Craig-Verteilung und Chromatographie trennen lassen. Es werden Bedingungen angegeben, unter denen Mono- und Diacetate des Phorbols durch selektive Veresterung bzw. Umesterung in einfacher Weise dargestellt werden können.
    Additional Material: 2 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/jlac.19677050123
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  • 6
    Electronic Resource
    Electronic Resource
    Zur Chemie des Phorbols, X1) Schweratom-Derivate zur Röntgenstrukturanalyse des PhorbolsHerrn Prof. Dr. H. Bredereck, Mitglied des Kuratoriums des Deutschen Krebsforschungszentrums, Heidelberg, in Verehrung zum 65. Geburtstag gewidmet. (1969)
    Weinheim : Wiley-Blackwell
    Liebigs Annalen 725 (1969), S. 130-141 
    Details
    ISSN: 0075-4617
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Chemistry of Phorbol, X1). Derivatives of Phorbol for X-Ray Structural AnalysisThe preparation of nine heavy atom derivatives of phorbol is described. They have been obtained by either esterification or hydrazone formation with bromine- or iodine- containing acids or hydrazines. Seven of these derivatives either remained resinous or crystallized in twin crystals. However, single crystals suitable for x-ray structural analysis have been obtained from 20-O-[p-brom-benzoyl]-phorbol-12,13-dibenzoate (6) and from 3-O-[p-brom-benzoyl]-neophorbol-13,20-diacetate (10). The structure of phorbol is derived from the structure and absolute configuration of 10, as revealed by x-ray analysis on the basis of the known chemistry of the functional groups and on n.m.r. data. Phorbol is a 4,9,12β,13,20-pentahydroxy-tiglia-1,6-diene-3-one.
    Notes: Die Darstellung von neun Schweratom-Derivaten des Phorbols durch Veresterung bzw. Hydrazon-Bildung mit Brom- oder Jod-haltigen Säuren bzw. Hydrazin-Abkömmlingen wird beschrieben. Sieben dieser Derivate erweisen sich entweder als harzartig oder kristallisieren in Zwillingskristallen. Zur Vermessung geeignete Einkristalle liefern das 20-O-[p-Brom-benzoyl]-phorbol-12.13-dibenzoat (6) und das 3-O[p-Brom-benzoyl]-neophorbol-13.20-diacetat (10). Aus der durch Röntgenstrukturanalyse ermittelten Struktur und absoluten Konfiguration von 10 ergibt sich auf Grund der bekannten Chemie der beteiligten funktionellen Gruppen sowie von NMR-Daten die Struktur des Phorbols als 4.9.12β.13.20-Pentahydroxytigliadien-(1.6)-on-(3).
    Additional Material: 1 Tab.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/jlac.19697250117
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  • 7
    Electronic Resource
    Electronic Resource
    Zur Chemie des Phorbols, XVI. 4α-Phorbol (1970)
    Weinheim : Wiley-Blackwell
    Liebigs Annalen 741 (1970), S. 13-32 
    Details
    ISSN: 0075-4617
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: On the Chemistry of Phorbol, XVI. 4α-PhorbolFrom the mother liquor of preparations of phorbol (1) an isomer 2 (isophorbol) is isolated. Chemical and spectroscopic data reveal that 2 is 4α-phorbol. 2 is obtained from 1 by basecatalyzed epimerization. In contrast to phorbol, base-catalyzed acetylation of 2 yields both 4α-phorbol-12,13,20-triacetate (3) and 4α-phorbol-4,12,13,20-tetraacetate (5). By methylation of 3 with methyl iodide/silver oxide in dimethylformamide three products are obtained: 4-O-methyl-4α-phorbol-12,13,20-triacetate (10), 4,13-di-O-methyl-4α-phorbol-12,20-diacetate (12)and 4-O-methyl-4α-phorbol-12,20-diacetate (11). On reduction with zinc/acetic acid, 3 yields 4-deoxy-4α-phorbol-12,13,20-triacetate (16).
    Notes: Aus der Mutterlauge der Phorbol-Darstellung wird eine mit Phorbol (1) isomere Verbindung 2 isoliert und aufgrund ihrer chemischen und spektroskopischen Eigenschaften als das 4α-Epimere von 1 (Isophorbol) identifiziert. 2 wird aus 1 durch Basen-katalysierte Epimerisierung erhalten. Die durch Basen katalysierte Acetylierung von 2 liefert, anders als jene von 1, neben 4α-Phorbol-12.13.20-triacetat (3) auch 4α-Phorbol-4.12.13.20-tetraacetat (5). Methylierung von 3 mit Methyljodid/Silberoxid in Dimethylformamid führt zu drei Methylierungsprodukten: 4-O-Methyl-4α-phorbol-12.13.20-triacetat(10), 4.13-Di-O-Methyl-4α-phorbol-12.20-diacetat (11) und 4-O-Methyl-4α-phorbol-12.20-diacetat (12). Reduktion von 3 mit Zink/Eisessig ergibt 4-Desoxy-4α-phorbol-12.13.20-triacetat (16).
    Additional Material: 3 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/jlac.19707410103
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  • 8
    Electronic Resource
    Electronic Resource
    Zur Chemie des Phorbols, XVII. Lumiphorbol und einige seiner Derivate (1971)
    Weinheim : Wiley-Blackwell
    Liebigs Annalen 748 (1971), S. 134-142 
    Details
    ISSN: 0075-4617
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: On the Chemistry of Phorbol, XVII. Lumiphorbol and Some of Its DerivativesIrradiation of the 4α-phorbol derivatives 1b-g with UV-light of 254 nm yields the isomeric „lumi-products“ 2b-g. By UV-, IR- and NMR-spectroscopic evidence, and by NMR-decoupling they are characterized as cage-like cyclobutane derivatives which are formed by intramolecular cycloaddition of the double bounds of 4α-phorbol. Phorbol derivatives do not undergo this lumi-reaction.
    Notes: Bei Bestrahlung der Derivate 1b-g des 4α-Phorbols (1a) mit UV-Licht (λmax = 254 nm) entstehen die isomeren „Lumiprodukte“ 2b-g. Sie werden mittels UV-, IR- und NMR-Spektren sowie durch Spin-Entkopplung als Produkte einer innermolekularen Cycloaddition der beiden Doppelbindungen des 4α-Phorbols zu einer Käfig-artigen Cyclobutan-Struktur charakterisiert. Derivate des Phorbols zeigen diese Lumireaktion nicht.
    Additional Material: 1 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/jlac.19717480115
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  • 9
    Electronic Resource
    Electronic Resource
    Zur Chemie der p-Chinole, X. Über das Östra-p-chinol-(10β) und die Umwandlung von p-Alkylphenolen in p-Alkylaniline über 4-Fluor-4-alkyl-dienone (1966)
    Weinheim : Wiley-Blackwell
    Liebigs Annalen 692 (1966), S. 174-179 
    Details
    ISSN: 0075-4617
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Die Darstellung von Östra-p-chinol-(10β) (5a) und seinem Acetat sowie des entsprechenden 10β-Fluor-Derivats wird beschrieben. Durch Einwirkung von Perchlorylfluorid auf p-Alkyl-phenole und Umsetzung der rohen 4-Fluor-4-alkyl-dienone mit 2.4-Dinitro-phenylhydrazin entstehen Derivate des 2.4-Dinitro-4-alkyl-azobenzols (z. B. 6) in guten Ausbeuten. Diese lassen sich reduzierend zu p-Alkylanilinen spalten, die den eingesetzten p-Alkylphenolen entsprechen. Auf diesem Wege werden 10β-Fluor-Δ1.4-östradien (5c) und 3-Amino-Δ1.3.5(10)-östratrien (7) dargestellt.
    Additional Material: 1 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/jlac.19666920120
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  • 10
    Electronic Resource
    Electronic Resource
    Zur Chemie des Phorbols, XIII1) Über eine Acyloin-Umlagerung des 12-Desoxy-12-oxo-phorbol-13.20-diacetatsHerrn Prof. Dr. H. Bredereck, Mitglied des Kuratoriums des Deutschen Krebsforschungszentrums, Heidelberg,in Verehrung zum 65. Geburtstag gewidmet. (1969)
    Weinheim : Wiley-Blackwell
    Liebigs Annalen 725 (1969), S. 142-153 
    Details
    ISSN: 0075-4617
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Chemistry of Phorbol, XIII. Acyloin Rearrangement of 12-Deoxy-12-oxophorbol- 13,20-diacetateOn reaction with sodium methylate in methanol 12-deoxy-12-oxophorbol-13,20-diacetate (1c) is readily and selectively transesterified in the 13-position to yield the derivative 1b having a free 12,13-ketol group. Under the conditions of the transesterification reaction the 12,13-ketol group undergoes an acyloin shift. Structure, stereochemistry, and mechanism of formation of the products of this rearrangement is established. Hydroxyphorbobutanone 4, and to a lesser extent the corresponding 20-acetate 3 resulting from migration of the C-14 anion, are formed as the main products. Hydroxyphorbo-isobutanone-semiketal-20-acetate 5 is formed to a lesser extent as product of the alternative migration of the C-15 anion. 4 is 4,9,12α,20-tetrahydroxy-14(13→12)abeo-(1,6)-tigliadiene-(3,13)-dione, 5 is 4,12β,13β-trihydroxy-20-acetoxy-9,13-epoxy-15(13→12)abeo-(1,6)-tigliadiene-(3)-one.
    Notes: 12-Desoxy-12-oxo-phorbol-13.20-diacetat (1c) wird mit methanolischer Natriummethylat-Lösung in die Verbindung 1b übergeführt, in der die 12.13-Ketol-Gruppe frei vorliegt. Unter den Bedingungen der Reaktion unterliegt 1b einer Acyloin-Verschiebung. Struktur, Stereochemie und Bildungsmechanismus der Umlagerungsprodukte werden geklärt. Als Hauptprodukte werden durch Wanderung des C-14-Anions das Hydroxyphorbobutanon 4, 4.9.12α.20-Tetrahydroxy-14(13→12)abeo-tigliadien-(1.6)-dion-(3.13) sowie dessen 20-Acetat 3 erhalten. In geringerer Menge wird als Folgeprodukt der alternativen Wanderung des C-15-Anions das 4.12β.13β-Trihydroxy-20-acetoxy-9.13-epoxy-15(13→12)abeo-tigliadien(1.6)-on-(3) (5) gebildet.
    Additional Material: 4 Tab.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/jlac.19697250118
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