Authors
He Y. Root MM. Parker RS. Campbell TC.
Institution
Division of Nutritional Scinces, Cornell University, Ithaca, NY 14853, USA.
Title
Effects of carotenoid-rich
food extracts on the development of preneoplastic lesions in
rat liver and on in vivo and in vitro antioxidant status.
Source
Nutrition & Cancer. 27(3):238-44, 1997.
Abstract
The effect of dietary carotenoid-rich extracts of carrots,
tomatoes, and orange juice on rat liver gamma-glutamyl
transpeptidase-positive preneoplastic foci induced by aflatoxin B1 was
investigated. Organic extracts were prepared from the foods,
dissolved in tricaprylin oil to equivalent concentrations of the major
food-specific carotenoids, and fed by intubation to Fischer
344 male rats. The extracts were administered during the 2-week
aflatoxin-dosing (initiation) period of the study or during the subsequent
12-week post-dosing (promotion) period. Vitamin status and antioxidant
activities were measured in blood and liver. Extract feeding caused an
accumulation of carotenoids in the liver, a substantial decrease in
spontaneous erythrocyte hemolysis, and lowered plasma glutathione, blood
superoxide dismutase, and blood catalase. Differences in foci development
among the three extracts were not as consistent or profound as differences
between initiation and promotion dosing. The number of gamma-glutamyl
transpeptidase-positive foci was decreased by extract feeding during the
initiation period, whereas extract feeding during the promotion period caused
a decrease in the average diameter of the foci. The total volume of foci was
markedly reduced by extract feeding during either period. Extracts were
compared with purified carotenoids and alpha-tocopherol in their ability to
affect in vitro antioxidation activity and were nearly as effective as the
pure compounds. In summary, carotenoid-rich extracts of
these three foods substantially inhibited biochemical and
cellular events thought to play a role in the early stages of
hepatocarcinogenesis.