EFFECT OF ALPHA-TOCOPHEROL ON CYTOTOXICITY INDUCED BY UV IRRADIATION AND ANTIOXIDANTS

Citation
H. Sakagami et al., EFFECT OF ALPHA-TOCOPHEROL ON CYTOTOXICITY INDUCED BY UV IRRADIATION AND ANTIOXIDANTS, Anticancer research, 17(3C), 1997, pp. 2079-2082
Citations number
11
Language
INGLESE
art.tipo
Article
Categorie Soggetti
Oncology
Journal title
ISSN journal
0250-7005
Volume
17
Issue
3C
Year of publication
1997
Pages
2079 - 2082
Database
ISI
SICI code
0250-7005(1997)17:3C<2079:EOAOCI>2.0.ZU;2-J
Abstract
The addition of DL-alpha-tocopherol (vitamin E) at the time of UV irra diation only marginally protects cells from UV-induced cytotoxicity. H owever, a protective effect of alpha-tocopherol emerged when it was ad ded to the cells before UV irradiation. alpha-Tocopherol was progressi vely and dose-dependently incorporated into the cells. Washout experim ents showed that the intracellular concentration of alpha-tocopherol d ecreased with an approximate half-life of 14-20 hours, due to the rele ase from the cells and dilution by cell proliferation. Pretreatment of the cells with alpha-tocopherol significantly increased the resistanc y against the cytotoxic action of UV irradiation and antioxidants such as sodium ascorbate, gallic acid, n-propyl gallate and caffeic acid. ESR spectroscopy showed that alpha-tocopherol enhanced the ascorbyl ra dical intensity, whereas it reduced caffeic acid radical intensity, wi thout affecting the radical intensity of gallic acid and n-propyl gall ate. Both control and treated cell lysates scavenged superoxide anion (generated by xanthine-xanthine oxidase reaction) and hydroxyl radical (generated by Fenton reaction) to a comparable extent. The present st udy suggests that the protective effect of alpha-tocopherol might be d erived from its incorporation into the cell membranes rather than its scavenging activity.