Disposition of glucosinolates and sulforaphane in humans after ingestion of steamed and fresh broccoli
Disposition of glucosinolates and sulforaphane in humans after ingestion of steamed and fresh broccoli
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DOI：
10.1207/s15327914nc382_5
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发表时间：
2000-01-01
影响因子：
2.9
通讯作者：
Chung, FL
中科院分区：
文献类型：
--
作者：
Conaway, CC;Getahun, SM;Chung, FL
西兰花的癌症化学预防作用可能部分归因于芥子油苷的水解产物异硫氰酸酯（ITC）。芥子油苷被黑芥子酶水解成各自的ITC，黑芥子酶被加热灭活。在这项研究中，硫代葡萄糖苷的代谢命运摄入后，蒸和新鲜西兰花进行了比较，在12名男性受试者的交叉设计。在每个48小时的基线期内，不允许食用含有硫代葡萄糖苷或ITC的食物。然后，受试者食用200克新鲜或蒸西兰花;排除所有其他饮食来源的ITC。在食用西兰花后的24小时内收集血液和尿液样本。西兰花中的总ITC当量以及血浆和尿液中的总ITC当量通过高效液相色谱法测定为1，2-苯二硫醇的环化缩合产物。发现黑芥子酶处理后新鲜和蒸过的西兰花中ITCs的含量几乎相同（1.1 μ mol/g湿重对1.0 μ mol/g湿重）。ITC当量的平均24小时尿液排泄量分别为新鲜和蒸西兰花摄入量的32.3 +/- 12.7%和10.2 +/- 5.9%。尿液中约40%的总ITC当量，新鲜和蒸西兰花分别为25.8 +/- 13.9和6.9 +/- 2.5 μ mol，以莱菔硫烷的N-乙酰基-L-半胱氨酸缀合物（SFN-NAC）形式存在。血浆中的总ITC代谢物在0至8小时之间达到峰值，而总ITC当量和SFN-NAC的尿排泄主要发生在2至12小时之间。这项研究的结果表明，ITCs从新鲜的西兰花的生物利用度是大约三倍以上，从煮熟的西兰花，其中黑芥子酶被灭活。考虑到ITC的癌症化学预防潜力，烹饪西兰花可能会显着减少其对健康的有益影响。
The cancer-chemopreventive effects of broccoli maybe 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 mu mol/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 mu mol 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.