Molecular and cellular activities of vitamin E analogues.
Natural vitamin E comprises 8 different analogues, the alpha-, beta-, gamma-, and delta-tocopherols and the alpha-, beta-, gamma-, and delta-tocotrienols. However, only alpha-tocopherol is selectively enriched by the liver; the other vitamin E analogues and also excess alpha-tocopherol are converted to several metabolites and eliminated. Recently, a novel phosphorylated form of tocopherol, alpha-tocopheryl phosphate, was shown to occur naturally in animal and human tissues as well as in foods. Several synthetic vitamin E derivatives have been synthesized that are either converted by esterases to the natural form, or exert novel or vitamin E related biological activities. During the last years, specific cellular effects for each individual vitamin E analogue have been described that are the consequence of modulating signal transduction and gene expression. These effects possibly reflect specific interactions of each of the vitamin E analogues with enzymes, structural proteins, lipids and transcription factors. In this review, the different natural vitamin E analogues and synthetic derivatives are compiled in relation to their major molecular and cellular activities.
Zingg
Jean-Marc
JM
Institute of Biochemistry and Molecular Medicine, University of Bern, Bühlstrasse 28, 3012 Bern, Switzerland. zin34@swissonline.ch
D000818:Animals; D000975:Antioxidants / Q000737:chemistry / Q000378:metabolism* / Q000494:pharmacology; D006801:Humans; D014810:Vitamin E / Q000031:analogs & derivatives* / Q000378:metabolism* / Q000494:pharmacology
D000975:Antioxidants; D014810:Vitamin E