Bheemreddy Radha M, Jeffery Elizabeth H
Department of Food Science and Human Nutrition, University of Illinois, 499 Bevier Hall, 905 South Goodwin Avenue, Urbana, Illinois 61801, USA.
J Agric Food Chem. 2007 Apr 18;55(8):2861-6. doi: 10.1021/jf0633544. Epub 2007 Mar 17.
Dietary broccoli is commonly eaten cooked, exposing individuals to intact glucoraphanin rather than to its hydrolysis product, the anticarcinogenic isothiocyanate sulforaphane, since cooking destroys the hydrolyzing enzyme myrosinase. There is little information on the absorption and metabolism of glucoraphanin, due partly to the lack of purified compound. In this study, glucoraphanin was purified from broccoli seed and 150 mumol/kg was administered to male F344 rats. Glucoraphanin (5% of an oral dose) was recovered intact in urine, showing that it is absorbed intact, and no glucoraphanin or metabolites were found in feces. Total urinary products accounted for 20 and 45% of oral and intraperitonneal doses, respectively, including sulforaphane N-acetyl cysteine conjugate (12.5 and 2%), free sulforaphane (0.65 and 0.77%), sulforaphane nitrile (2 and 1.4%), and erucin (0.1 and 0.1%), respectively. Both glucoraphanin and its reduced form glucoerucin were identified in bile following intravenous glucoraphanin administration. We conclude that orally administered glucoraphanin is absorbed intact, undergoes enterohepatic circulation, and is hydrolyzed in the gut in F344 rats.
日常食用的西兰花通常是经过烹饪的，这样人们摄入的是完整的萝卜硫苷，而非其水解产物——具有抗癌作用的异硫氰酸酯萝卜硫素，因为烹饪会破坏水解酶黑芥子酶。关于萝卜硫苷的吸收和代谢情况，目前所知甚少，部分原因是缺乏纯化的化合物。在本研究中，从西兰花种子中纯化出萝卜硫苷，并以150微摩尔/千克的剂量给雄性F344大鼠给药。萝卜硫苷（口服剂量的5%）完整地在尿液中被回收，表明它能完整地被吸收，且在粪便中未发现萝卜硫苷或其代谢产物。尿液中的总产物分别占口服剂量和腹腔注射剂量的20%和45%，其中包括萝卜硫素N - 乙酰半胱氨酸共轭物（分别为12.5%和2%）、游离萝卜硫素（0.65%和0.77%）、萝卜硫素腈（2%和1.4%）以及芥酸（0.1%和0.1%）。静脉注射萝卜硫苷后，在胆汁中鉴定出了萝卜硫苷及其还原形式葡萄糖芥苷。我们得出结论，口服的萝卜硫苷能完整地被吸收，进行肠肝循环，并在F344大鼠的肠道中被水解。
