Authors
Ip C. Lisk DJ.
Institution
Department of Surgical Oncology, Roswell Park Cancer Institute, Buffalo, NY
14263.
Title
Characterization of tissue selenium profiles and anticarcinogenic responses
in rats fed natural sources of selenium-rich products.
Source
Carcinogenesis. 15(4):573-6, 1994 Apr.
Abstract
The present report describes the biological effects associated with the
feeding of three selenium-rich natural products in rats: high-selenium
garlic, high-selenium onion and Brazil nut.
The first two are experimental crops cultivated with selenium fertilization.
Brazil nut is probably the only
unadulterated high-selenium food that is available commercially. Tissue
selenium profiles, liver glutathione concentrations and mammary cancer
inhibition (in the dimethylbenz[a] anthracene model) were the endpoints of
investigation. Parallel designs were set up to compare the three
high-selenium products with selenite and selenomethionine. Previous studies
have shown that treatment with seleno-methionine resulted in significantly
greater tissue selenium accumulation, particularly in skeletal muscle, than
treatment with selenite. In contrast, selenite, but not selenomethionine,
induced a modest increase in liver glutathione concentrations. The objective
was to determine whether the high-selenium natural products elicited
responses that were similar to that of selenite or selenomethionine. Our
experiments suggested that the high-selenium garlic and onion might have some
unique attributes. First, their ingestion did not lead to an exaggerated
accumulation of tissue selenium, a concern that was shared by both
selenomethionine and Brazil nut. Second,
unlike selenite, they did not cause any perturbation in glutathione
homeostasis. Third, they expressed good anticancer activity that was equal
to, if not better than, that of selenite. The chemical form(s) of selenium
present in the high-selenium Allium vegetables will be discussed in relation
to the manifestation of the above characteristics.