Talk:Glucosinolate
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Suggestion for revision of the passage about cancer-preventing activity
[edit]I would like to discuss the following passage from the current glucosinolate article: "Consumers of higher levels of Brassica vegetables, particularly those of the genus Brassica (broccoli, Brussels sprouts and cabbage), reduce their susceptibility to cancer at a variety of organ sites. Brassica vegetables contain high concentrations of glucosinolates that can be hydrolyzed by the plant enzyme, myrosinase, or intestinal microflora to isothiocyanates, potent inducers of cytoprotective enzymes and inhibitors of carcinogenesis. These findings provide a strong rationale for evaluating the protective effects of a broccoli sprout preparation in clinical trials of women at risk for breast cancer (Reference)."
My feeling is that this is one-sided, and has a touch of promoting a particular research project. In particular, I am afraid that there is not general agreement about the opening phrase "Consumers of higher levels of Brassica vegetables, particularly those of the genus Brassica (broccoli, Brussels sprouts and cabbage), reduce their susceptibility to cancer at a variety of organ sites". The recent reviews I know of (but I am not an expert on the medical aspects of glucosinolates) do not support this statement.
I propose revision.
April 28, Niels Agerbirk, University of Copenhagen.Niels Agerbirk (talk) 20:47, 28 April 2010 (UTC)
PubMed cite to study: 2/3 reduction of glucosinolates and sulforaphane in fresh broccoli after steaming.
[edit]This was the only study I easily found for the often-repeated claim that cooking reduces the goitrogenic properties of cruciferous vegetables.
http://www.ncbi.nlm.nih.gov/pubmed/11525594
Conaway CC, Getahun SM, Liebes LL, Pusateri DJ, Topham DK, Botero-Omary M, Chung FL.
Disposition of glucosinolates and sulforaphane in humans after ingestion of steamed and fresh broccoli.
Nutr Cancer. 2000;38(2):168-78.
Erratum in Nutr Cancer 2001;41(1-2):196.
Abstract
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 micromol/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 micromol 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.
PMID 11525594 — Preceding unsigned comment added by 99.190.133.143 (talk) 21:11, 28 January 2012 (UTC)
Opening paragraph is poor.
[edit]The opening paragraph will mean precisely nothing to someone who is not a botanist and/or a biochemist. This kind of technical jargon should be later in the article. The opening paragraph should be readable to someone who isn't a specialist in that topic. — Preceding unsigned comment added by 184.147.122.74 (talk) 17:13, 22 April 2013 (UTC)
Hi anonymous: Thanks for this input. I've tried improving as suggested. What do you think of the changed opening paragraph? Feb. 6, 2014, Niels Agerbirk — Preceding unsigned comment added by Niels Agerbirk (talk • contribs) 21:08, 6 February 2014 (UTC)