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PLoS One. 2008 Jul 2;3(7):e2568.

Broccoli consumption interacts with GSTM1 to perturb oncogenic signalling pathways in the prostate.

Traka M, Gasper AV, Melchini A, Bacon JR, Needs PW, Frost V, Chantry A, Jones AM, Ortori CA, Barrett DA, Ball RY, Mills RD, Mithen RF.

Phytochemicals and Health Programme, Institute of Food Research, Norwich Research Park , Norwich , United Kingdom .

BACKGROUND: Epidemiological studies suggest that people who consume more than one portion of cruciferous vegetables per week are at lower risk of both the incidence of prostate cancer and of developing aggressive prostate cancer but there is little understanding of the underlying mechanisms. In this study, we quantify and interpret changes in global gene expression patterns in the human prostate gland before, during and after a 12 month broccoli-rich diet . METHODS AND FINDINGS: Volunteers were randomly assigned to either a broccoli-rich or a pea-rich diet. After six months there were no differences in gene expression between glutathione S-transferase mu 1 (GSTM1) positive and null individuals on the pea-rich diet but significant differences between GSTM1 genotypes on the broccoli-rich diet, associated with transforming growth factor beta 1 (TGFbeta1) and epidermal growth factor (EGF) signalling pathways. Comparison of biopsies obtained pre and post intervention revealed more changes in gene expression occurred in individuals on a broccoli-rich diet than in those on a pea-rich diet. While there were changes in androgen signalling, regardless of diet, men on the broccoli diet had additional changes to mRNA processing, and TGFbeta1, EGF and insulin signalling. We also provide evidence that sulforaphane (the isothiocyanate derived from 4-methylsuphinylbutyl glucosinolate that accumulates in broccoli) chemically interacts with TGFbeta1, EGF and insulin peptides to form thioureas, and enhances TGFbeta1/Smad-mediated transcription. CONCLUSIONS: These findings suggest that consuming broccoli interacts with GSTM1 genotype to result in complex changes to signalling pathways associated with inflammation and carcinogenesis in the prostate. We propose that these changes may be mediated through the chemical interaction of isothiocyanates with signalling peptides in the plasma. This study provides, for the first time, experimental evidence obtained in humans to support observational studies that diets rich in cruciferous vegetables [such as broccoli] may reduce the risk of prostate cancer and other chronic disease

Source: PubMed

Disposition of Glucosinolates and Sulforaphane in Humans After Ingestion of Steamed and Fresh Broccoli 

Authors: C. Clifford Conaway ; Serkadis M. Getahun ; Leonard L. Liebes ; Donald J. Pusateri ; Debra K. W. Topham ; Mar iacutea Botero-Omary ;Fung-Lung Chung

DOI: 10.1207/S15327914NC382_5

Published in: Nutrition and Cancer, Volume 38, Issue 2 November 2000 , pages 168 – 178

The cancer-chemopreventive effects of broccoli may be attributed, in part, to isothiocyanates (ITCs), hydrolysis products of glucosinolates . Glucosinolates are hydrolyzed to their respective ITCs by the enzyme myrosinase, which is inactivated by heat. In this study, the metabolic fate of glucosinolates after ingestion of steamed and fresh broccoli was compared in 12 male subjects in a crossover design. During each 48-hour baseline period, no foods containing glucosinolates or ITCs were allowed. The subjects then consumed 200 g of fresh or steamed broccoli; all other dietary sources of ITCs were excluded. Blood and urine samples were collected during the 24-hour period after broccoli consumption. Total ITC equivalents in broccoli and total ITC equivalents in plasma and urine were assayed by high-performance liquid chromatography as the cyclocondensation product of 1,2-benzenedithiol. The content of ITCs in fresh and steamed broccoli after myrosinase treatment was found to be virtually identical (1.1 vs. 1.0 μmol/g wet wt). The average 24-hour urinary excretion of ITC equivalents amounted to 32.3 ± 12.7% and 10.2 ± 5.9% of the amounts ingested for fresh and steamed broccoli, respectively. Approximately 40% of total ITC equivalents in urine, 25.8 ± 13.9 and 6.9 ± 2.5 μmol for fresh and steamed broccoli, respectively, occurred as the N-acetyl-L-cysteine conjugate of sulforaphane (SFN-NAC). Total ITC metabolites in plasma peaked between 0 and 8 hours, whereas urinary excretion of total ITC equivalents and SFN-NAC occurred primarily between 2 and 12 hours. Results of this study indicate that the bioavailability of ITCs from fresh broccoli is approximately three times greater than that from cooked broccoli, in which myrosinase is inactivated. Considering the cancer-chemopreventive potential of ITCs, cooking broccoli may markedly reduce its beneficial effects on health.

Source: Nutrition and Cancer, Volume 38, Issue 2 November 2000 , pages 168 – 178

Curr Eye Res. 2010 Feb;35(2):99-107.

Broccoli regulates protein alterations and cataractogenesis in selenite models.

Vibin M, Siva Priya SG, N Rooban B, Sasikala V, Sahasranamam V, Abraham A.

Department of Biochemistry, University of Kerala , Kariavattom, Thiruvananthapuram , India .

Purpose: To study the efficacy of Brassica oleracea var. italica (Broccoli) in the prevention of selenite induced biochemical changes and the incidence of cataractogenesis in vivo. Methods: Eight day old Sprague-Dawley rat pups were divided into four groups: I-Control; II-Sodium selenite (4 mg/kg body weight) administered; III-Sodium selenite + quercetin; and IV-Sodium selenite + flavonoid fraction of broccoli (FFB). Treatment groups III and IV received quercetin and FFB intraperitoneally from 8th to 15th day at a concentration (2.0 mg/kg body weight). The development of cataract was assessed and graded by slit-lamp examination. Some relevant biochemical parameters-such as activities of superoxide dismutase (SOD), catalase, Ca(2+)ATPase, calpains, concentration of reduced glutathione (GSH), levels of calcium, lipid peroxidation product-thiobarbituric acid reacting substances (TBARS) and SDS-PAGE analysis of lens water soluble proteins (WSF) were analyzed. Results: FFB modulates selenite-induced biochemical changes in albino rats. Lenses of Group I rats were clear but in Group II, all lenses developed dense opacification (grade 5 and 6), whereas mild opacifications were observed in Group III and Group IV (grade 2). Group III and Group IV lenses exhibited significantly higher values of antioxidant enzymes, Ca(2+)ATPase, and GSH, whereas lower values were obtained for TBARS, calcium, and calpains compared to Group II. Lens protein profile of water soluble proteins showed normal levels of Group III and Group IV compared to Group II lenses. Conclusion: FFB prevents selenite-induced cataractogenesis in albino rat pups, possibly by maintaining antioxidant status and ionic balance through Ca(2+) ATPase pump, inhibition of lipid peroxidation, calpain activation, and protein insolubilization, which have been reported in this article for the first time .

Source: PubMed