Official websites use. Share sensitive information only on official, secure websites. Induction of phase 2 detoxication enzymes [e. Since consumption of large quantities of fruit and vegetables is associated with a striking reduction in the risk of developing a variety of malignancies, it is of interest that a number of edible plants contain substantial quantities of compounds that regulate mammalian enzymes of xenobiotic metabolism.
Thus, edible plants belonging to the family Cruciferae and genus Brassica e. Unexpectedly, 3-day-old sprouts of cultivars of certain crucifers including broccoli and cauliflower contain 10β times higher levels of glucoraphanin the glucosinolate of sulforaphane than do the corresponding mature plants. Extracts of 3-day-old broccoli sprouts containing either glucoraphanin or sulforaphane as the principal enzyme inducer were highly effective in reducing the incidence, multiplicity, and rate of development of mammary tumors in dimethylbenz a anthracene-treated rats.
Notably, sprouts of many broccoli cultivars contain negligible quantities of indole glucosinolates, which predominate in the mature vegetable and may give rise to degradation products e. Hence, small quantities of crucifer sprouts may protect against the risk of cancer as effectively as much larger quantities of mature vegetables of the same variety. Keywords: chemoprotection, glucosinolates, isothiocyanates, sulforaphane, glucoraphanin.
Many types of chemoprotectors against cancer evoke large inductions of phase 2 enzymes of xenobiotic metabolism and increase glutathione levels in animal tissues 1. These cellular responses accelerate the detoxication of electrophiles and reactive forms of oxygen, and thereby protect cells against mutagenesis and neoplasia.
Substantial evidence suggests that induction of these detoxication enzymes provides a major strategy for achieving protection against malignancy 1. The chemical specificity of the inducers and the molecular mechanisms of regulation of phase 2 enzymes are under active investigation in several laboratories 2 β 6. Edible plants contain a wide variety of minor metabolites, some of which are phase 2 enzyme inducers. Since extensive epidemiological evidence, backed by animal experiments, shows that diets rich in fruits and vegetables are associated with large and dose-related reductions in the risk of developing cancer 7 β 10 , it is likely that these metabolites are at least partially responsible for protection.
