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Cis-trans Isomerism and Provitamin A Effect of Carotenoids

  • L. Ƶechmeister

Abstract

The chemical and biological relationships between carotene and vitamin A have been established by the classical investigations of Steenbock (412), Moore (320), Euler (111), Karrer (112), and others. It is now well known that β-carotene whose molecules contain two unsubstituted β-ionone rings is partially converted in the body into vitamin A, according to the schematic expression, C40H56 → C20H29OH. Several other naturally occurring carotenoids such as α-carotene, γ-carotene, and cryptoxanthin undergo analogous cleavage but in these instances only one half of each molecule may theoretically yield the bio- active substance. Although the postulate that at least one unsubstituted β-ionone ring must be present in provitamins A has been rather generally accepted, there are some exceptions. For example, 2,2′-dimethyl-β-carotene is effective in the rat to the extent of one half of the β-carotene potency [Eugster, Trivedi and Karrer (110)].

Keywords

Terminal Double Bond Analogous Cleavage Isomeric Carotenoid Short Wavelength Maximum Altered Configuration 
These keywords were added by machine and not by the authors. This process is experimental and the keywords may be updated as the learning algorithm improves.

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Copyright information

© Springer-Verlag Vienna 1962

Authors and Affiliations

  • L. Ƶechmeister
    • 1
  1. 1.California Institute of TechnologyPasadenaUSA

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