Broccoli Sprouts in Cancer Prevention
Nutr Rev 1998 (Apr); 56 (4 Pt 1): 127–130
Recent research has aimed to identify specific phytochemicals in Brassica vegetables, such as sulforaphane in broccoli, that may confer protection against cancer. Clinical, dietary, and policy implications are discussed.
Brassica Vegetables and Cancer Prevention: Epidemiology and Mechanisms
Adv Exp Med Biol 1999; 472: 159–168
Most evidence concerning anticarcinogenic effects of glucosinolate hydrolysis products and brassica vegetables has come from studies in animals. In addition, studies carried out in humans using high but still realistic human consumption levels of indoles and brassica vegetables have shown putative positive effects on health. The combination of epidemiological and experimental data provide suggestive evidence for a cancer preventive effect of a high intake of brassica vegetables.
Broccoli Sprouts as Inducers of Carcinogen-detoxifying Enzyme Systems: Clinical, Dietary, and Policy Implications
Proc Natl Acad Sci USA 1997 (Oct 14); 94 (21): 11149–11151
Epidemiologic and animal studies have associated certain food plants with pronounced reductions in cancer risk. Among such plants are cruciferous (mustard family) vegetables of the genus Brassica: broccoli, cabbage, cauliflower, and Brussels sprouts, among others. National committees have recommended consumption of these vegetables for cancer prevention since the early 1980s 1(2)
Broccoli Sprouts: An Exceptionally Rich Source of Inducers of Enzymes That Protect Against Chemical Carcinogens
Proc Natl Acad Sci USA 1997 (Sep 16); 94 (19): 10367–10372
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.g., indole-3- carbinol) that can enhance tumorigenesis. 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.
A Major Inducer of Anticarcinogenic Protective Enzymes from Broccoli: Isolation and Elucidation of Structure
Proc Natl Acad Sci U S A 1992 (Mar 15); 89 (6): 2399–2403
To elucidate the structural features responsible for the high inducer potency of sulforaphane, we synthesized racemic sulforaphane and analogues differing in the oxidation state of sulfur and the number of methylene groups: CH3-SOm-(CH2)n-NCS, where m = 0, 1, or 2 and n = 3, 4, or 5, and measured their inducer potencies in murine hepatoma cells. Sulforaphane is the most potent inducer, and the presence of oxygen on sulfur enhances potency. Sulforaphane and its sulfide and sulfone analogues induced both quinone reductase and glutathione transferase activities in several mouse tissues. The induction of detoxication enzymes by sulforaphane may be a significant component of the anticarcinogenic action of broccoli.