Cruciferous Vegetables: Cancer Protective Mechanisms of Glucosinolate Hydrolysis Products and Selenium

Abstract

Dietetic professionals urge Americans to increase fruit and vegetable intakes. The American Institute of Cancer Research estimates that if the only dietary change made was to increase the daily intake of fruits and vegetables to 5 servings per day, cancer rates could decline by as much as 20%. Among the reasons cited for this health benefit are that fruits and vegetables are excellent sources of fiber, vitamins, and minerals. They also contain nonnutritive components that may provide substantial health benefits beyond basic nutrition. Examples of the latter are the glucosinolate hydrolysis products, sulforaphane, and indole-3-carbinol. Epidemiological studies provide evidence that the consumption of cruciferous vegetables protects against cancer more effectively than the total intake of fruits and vegetables. This review describes the anticarcinogenic bioactivities of glucosinolate hydrolysis products, the mineral selenium derived from crucifers, and the mechanisms by which they protect against cancer. These mechanisms include altered estrogen metabolism, protection against reactive oxygen species, altered detoxification by induction of phase II enzymes, decreased carcinogen activation by inhibition of phase I enzymes, and slowed tumor growth and induction of apoptosis.

Indole-3-carbinol inhibits cell proliferation and induces apoptosis in Hep-2 laryngeal cancer cells

“…Indole-3-carbinol is extracted from cruciferous vegetables by hydrolysis of glucosinolates (6). Many previous in vitro studies have shown that I3C causes significant growth inhibition of a variety of tumor cell lines by inducing cell cycle arrest and apoptosis (8,10,12,17,18).…”

“…For example, epidemiological studies suggest that the intake of broccoli, cauliflower and other cruciferous vegetables can significantly reduce the incidence of cancers of the bladder, pancreas, colon, lung and stomach (2)(3)(4)(5). Indole-3-carbinol (I3C) has recently been identified as an important tumoricidal component found in cruciferous vegetables and particularly in members of the genus Brassica (6,7). A number of studies have shown that I3C induces cell cycle arrest in the G1 phase in cancer cells (8,9), promotes apoptosis (8)(9)(10) and prevents tumor invasion and metastasis (11).…”

Modifiable lifestyle factors and ovarian cancer incidence in women

“…Tests on animals and in vitro tests drew attention to the degradation products of glucosinolates which suppress the division of cancer cells, and accelerate the controlled death of the cell with damaged DNA. Furthermore, the protective effect of the enzyme degradation products of glucosinolates is associated with the induction of detoxifying enzymes in the tissues of the gastrointestinal tract, particularly of glutathione transferase, levelling the active form of carcinogenic compounds [21,22,23].…”

Metabolic engineering of aliphatic glucosinolates in Chinese cabbage plants expressing Arabidopsis MAM1, CYP79F1, and CYP83A1

“…They have recently attracted considerable attention because of a wide range of bioactivities, including functioning as antimicrobial compounds (1,2), deterrents of generalist herbivores (3), herbicides (4), and anticarcinogenic agents (5). Sulforaphane, a metabolite of methionine-derived 4-methylsulfinylbutyl glucosinolate (glucoraphanin), has received special attention because of its potent anticarcinogenic activity (6,7).…”