EFFECTS OF CAROTENOID-RICH FOOD EXTRACTS ON THE DEVELOPMENT OF PRENEOPLASTIC LESIONS IN RAT-LIVER AND ON IN-VIVO AND IN-VITRO ANTIOXIDANT STATUS

The effect of dietary carotenoid-rich extracts of carrots, tomatoes, a nd orange juice on rat liver gamma-glutamyl transpeptidase-positive pr eneoplastic foci induced by aflatoxin B-1 was investigated. Organic ex tracts were prepared from the foods, dissolved in tricaprylin oil to e quivalent concentrations of the major food-specific carotenoids, and f ed by intubation to Fischer 344 male rats. The extracts were administe red during the 2-week aflatoxin-dosing (initiation) period of the stud y or during the subsequent 12-week postdosing (promotion) period. Vita min 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 Lower ed 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 ex tract feeding during the promotion period caused a decrease in the ave rage diameter of the foci. The total volume of foci was markedly reduc ed by extract feeding during either period. Extracts were compared wit h purified carotenoids and cr-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 pla y a role in the early stages of hepatocarcinogenesis.