Library

feed icon rss

Your email was sent successfully. Check your inbox.

An error occurred while sending the email. Please try again.

Proceed reservation?

Export
  • 1
    ISSN: 0887-6134
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Steviol (ent-13-hydroxykaur-16-en-19-oic acid), the aglycone of various plant-derived glycoside sweeteners consumed by human populations, is known to be mutagenic toward Salmonella typhimurium strain TM677 when metabolically activated using a 9000 × g supernatant fraction derived from the liver of Aroclor 1254-pretreated rats. Mass spectral analysis of this diterpenoid and some analogs revealed characteristic patterns reflecting differential stereochemistry at the C/D rings and variations in the nature of the substituents present. Such information has been used to help identify several in vitro metabolites of steviol in conditions known to produce a mutagenic response, when analyzed by human populations, is known to be mutagenic toward Salmonella typhimurium strain TM677 when metabolically be allylic oxidation and epoxidation. 15-Oxosteviol, a product of oxidation of the major steviol metabolite, 15α-hydroxysteviol, was found to be a direct-acting mutagen.
    Additional Material: 10 Ill.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 2
    Electronic Resource
    Electronic Resource
    Chichester : Wiley-Blackwell
    Biological Mass Spectrometry 2 (1975), S. 126-130 
    ISSN: 1052-9306
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: A method is described for the micro-identification of both mono- and diesters of 12-deoxyphorbol based upon a combination of thin-layer chromatography and mass spectrometry. The technique may be used on as little as 5 ml of fresh plant latex. Nine thin-layer systems are described, six of which are adsorption systems based on silica gel or alumina as adsorbent, and three are partition systems using diethyleneglycol as stationary phase. The migration by means of thin-layer chromatography is dependent upon the chain length of the C-13 esterifying acid and on the presence or absence of a free primary hydroxyl group at C-20. By means of mass spectrometry it was possible to confirm the identity of the esterifying moiety at both the C-13 and C-20 positions of 12-deoxy-4βOH-phorbol.
    Additional Material: 4 Tab.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 3
    ISSN: 1052-9306
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The use the naturally occurring ent-kaurene diterpene glycoside, stevioside, as a sucrose substitute in several countries has resulted in the need for improved methods to analyze its potential metabolites. Altogether 21 diterpenes related in structure to steviol, the aglycone of stevioside, have been subjected to desorption chemical ionization mass spectrometry using methane, ammonia and dimethyl ether as reagent gases. Both methane and ammonia provided the molecular weights of these derivatives, but failed to produce any adduct ions of particular diagnositc value for differentiating compounds in the steviol series. On the other hand, dimethyl ether produced positive ion chemical ionization spectra that differed according to the nature of the functional groups represented among the steviol derivatives examined. Prominent adduct ions observed using dimethyl ether were [M + 1 - 18]+, [M + 1]+, [M + 45 - 32]+, [M + 45]+ and [M + 47]+. Mechanisms have been proposed for the formation of these adducts.
    Additional Material: 6 Ill.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
Close ⊗
This website uses cookies and the analysis tool Matomo. More information can be found here...