glucoraphanin and erucin

Sulphoraphane originates from glucoraphanin in broccoli and is associated with anti-cancer effects. A preclinical study suggested that daily consumption of broccoli may increase the production of sulphoraphane and sulphoraphane metabolites available for absorption. The objective of this study was to determine whether daily broccoli consumption alters the absorption and metabolism of isothiocyanates derived from broccoli glucosinolates. We conducted a randomised cross-over human study (n 18) balanced for BMI and glutathione S-transferase μ 1 (GSTM1) genotype in which subjects consumed a control diet with no broccoli (NB) for 16 d or the same diet with 200 g of cooked broccoli and 20 g of raw daikon radish daily for 15 d (daily broccoli, DB) and 100 g of broccoli and 10 g of daikon radish on day 16. On day 17, all subjects consumed a meal of 200 g of broccoli and 20 g of daikon radish. Plasma and urine were collected for 24 h and analysed for sulphoraphane and metabolites of sulphoraphane and erucin by triple quadrupole tandem MS. For subjects with BMI >26 kg/m2 (median), plasma AUC and urinary excretion rates of total metabolites were higher on the NB diet than on the DB diet, whereas for subjects with BMI <26 kg/m2, plasma AUC and urinary excretion rates were higher on the DB diet than on the NB diet. Daily consumption of broccoli interacted with BMI but not GSTM1 genotype to affect plasma concentrations and urinary excretion of glucosinolate-derived compounds believed to confer protection against cancer. This trial was registered as NCT02346812.

Topics: Acetylcysteine; Adult; Aged; Anticarcinogenic Agents; Area Under Curve; Body Mass Index; Brassica; Cooking; Cross-Over Studies; Diet; Female; Genotype; Glucose; Glucosinolates; Glutathione Transferase; Glycoside Hydrolases; Humans; Imidoesters; Isothiocyanates; Male; Mannitol; Middle Aged; Oximes; Raphanus; Sulfides; Sulfoxides; Tandem Mass Spectrometry; Thiocyanates

Sulforaphane (a potent anticarcinogenic isothiocyanate derived from glucoraphanin) is widely considered responsible for the protective effects of broccoli consumption. Broccoli is typically purchased fresh or frozen and cooked before consumption. We compared the bioavailability and metabolism of sulforaphane from portions of lightly cooked fresh or frozen broccoli, and investigated the bioconversion of sulforaphane to erucin.. Eighteen healthy volunteers consumed broccoli soups produced from fresh or frozen broccoli florets that had been lightly cooked and sulforaphane thio-conjugates quantified in plasma and urine. Sulforaphane bioavailability was about tenfold higher for the soups made from fresh compared to frozen broccoli, and the reduction was shown to be due to destruction of myrosinase activity by the commercial blanching-freezing process. Sulforaphane appeared in plasma and urine in its free form and as several thio-conjugates forms. Erucin N-acetyl-cysteine conjugate was a significant urinary metabolite, and it was shown that human gut microflora can produce sulforaphane, erucin, and their nitriles from glucoraphanin.. The short period of blanching used to produce commercial frozen broccoli destroys myrosinase and substantially reduces sulforaphane bioavailability. Sulforaphane was converted to erucin and excreted in urine, and it was shown that human colonic flora were capable of this conversion.

Topics: Adult; Aged; Anticarcinogenic Agents; Biological Availability; Brassica; Cross-Over Studies; Female; Food Handling; Freezing; Gastrointestinal Tract; Glucosinolates; Glycoside Hydrolases; Humans; Imidoesters; Isothiocyanates; Kinetics; Male; Metagenome; Middle Aged; Oximes; Sulfides; Sulfoxides; Thiocyanates; Young Adult

Certain myrosinase-positive human gut bacteria can metabolize glucosinolates (GSLs) to produce isothiocyanates (ITC) as chemopreventive agents. We investigated glucoerucin, glucoiberin, and glucoraphanin (present in broccoli) metabolism by human gut strains.. All tested bacteria metabolized glucoerucin to completion within 16 h to erucin and erucin nitrile (NIT). Lactobacillus agilis R16 metabolized only 10% of glucoiberin and glucoraphanin with no detectable products. Enterococcus casseliflavus CP1, however, metabolized 40-50% of glucoiberin and glucoraphanin producing relatively low concentrations of iberin and sulforaphane. Interestingly, Escherichia coli VL8 metabolized 80-90% of glucoiberin and glucoraphanin and also bioconverted glucoraphanin and glucoiberin to glucoerucin and glucoiberverin, respectively, producing erucin, erucin NIT, iberverin, and iberverin NIT from the two GSLs. The putative reductase enzyme in the cell-free extracts of this bacterium required both Mg(2+) and NAD(P)H as cofactors for bioconversion. The cell-free extract of E. coli VL8 containing the reductase enzyme was able to reduce both the GSL glucoraphanin and its hydrolysis product sulforaphane to glucoerucin and erucin/erucin NIT, respectively.. The composition and metabolic activity of the human gut bacteria can indirectly impact on the potential chemopreventive effects of GSL-derived metabolites.

Topics: Brassica; Cell-Free System; Enterococcus; Escherichia coli; Gastrointestinal Tract; Glucose; Glucosinolates; Humans; Imidoesters; Isothiocyanates; Lactobacillus; Oximes; Sulfides; Sulfoxides; Thiocyanates

Broccoli sprouts are a rich source of glucosinolates, a group of phytochemicals that when hydrolyzed, are associated with cancer prevention. Our objectives were to investigate the metabolism, distribution, and interconversion of isothiocyanates (ITCs) in mice fed thermally processed broccoli sprout powders (BSPs) or the purified ITC sulforaphane.. For 1 wk, mice were fed a control diet (n = 20) or one of four treatment diets (n = 10 each) containing nonheated BSP, 60°C mildly heated BSP, 5-min steamed BSP, or 3 mmol purified sulforaphane. Sulforaphane and erucin metabolite concentrations in skin, liver, kidney, bladder, lung, and plasma were quantified using HPLC-MS/MS. Thermal intensity of BSP processing had disparate effects on ITC metabolite concentrations upon consumption. Mild heating generally resulted in the greatest ITC metabolite concentrations in vivo, followed by the nonheated and steamed BSP diets. We observed interconversion between sulforaphane and erucin species or metabolites, and report that erucin is the favored form in liver, kidney, and bladder, even when only sulforaphane is consumed.. ITC metabolites were distributed to all tissues analyzed, suggesting the potential for systemic benefits. We report for the first time tissue-dependent ratio of sulforaphane and erucin, though further investigation is warranted to assess biological activity of individual forms.

Topics: Animals; Anticarcinogenic Agents; Brassica; Dietary Supplements; Female; Food Handling; Freeze Drying; Functional Food; Glucose; Glucosinolates; Hot Temperature; Imidoesters; Isothiocyanates; Kidney; Liver; Mice, Hairless; Organ Specificity; Oximes; Plant Shoots; Sulfides; Sulfoxides; Thiocyanates; Urinary Bladder; Weight Gain

Various analytical methods have been established to quantify isothiocyanates (ITCs) that derive from glucosinolate hydrolysis. However, to date there is no valid method applicable to pharmacokinetic studies that detects both glucosinolates and ITCs. A specific derivatization procedure was developed for the determination of ITCs based on the formation of a stable N-(tert-butoxycarbonyl)-L-cysteine methyl ester derivative, which can be measured by high-performance liquid chromatography with ultraviolet detection after extraction with ethylacetate. The novel method, which is also applicable to the indirect determination of glucosinolates after their hydrolysis by myrosinase, was established for the simultaneous determination of glucoraphanin and sulforaphane. By derivatization, the sensitivity of ITC detection was increased 2.5-fold. Analytical recoveries from urine and plasma were greater than 75% and from feces were approximately 50%. The method showed intra- and interday variations of less than 11 and 13%, respectively. Applicability of the method was demonstrated in mice that received various doses of glucoraphanin or that were fed a glucoraphanin-rich diet. Besides glucoraphanin and sulforaphane, glucoerucin and erucin were detected in urine and feces of mice. The novel method provides an essential tool for the analysis of bioactive glucosinolates and their hydrolysis products and, thus, will contribute to the elucidation of their bioavailability.

Topics: Animals; Chromatography, High Pressure Liquid; Cystine; Feces; Glucose; Glucosinolates; Hydrolysis; Imidoesters; Isothiocyanates; Male; Mice; Mice, Inbred C57BL; Oximes; Sulfides; Sulfoxides; Thiocyanates

It is believed that the chemopreventive activity of cruciferous vegetables in the lung and other tissues is exclusively the result of exposure to degradation products of glucosinolates, such as the isothiocyanates, and that the parent glucosinolates make no contribution. In the present study, evidence is presented for the first time that, in rat lung, the intact glucosinolates, glucoraphanin and glucoerucin, can modulate carcinogen-metabolising enzyme systems. The glucosinolates were isolated from cruciferous vegetables and incubated (1-25 μM) with precision-cut rat lung slices for 24h. Both glucosinolates, at concentrations as low as 1 μM, up-regulated the O-deethylation of ethoxyresorufin and the apoprotein levels of CYP1A1 and CYP1B1; supplementation of the incubation medium with myrosinase, the enzyme that converts glucosinolates to their corresponding isothiocyanates, abolished the rise in ethoxyresorufin O-deethylase activity. In contrast, neither glucosinolate, at the concentrations studied, influenced quinone reductase activity in the lung slices, but addition of myrosinase to the glucosinolate incubations led to a marked rise in activity. Glutathione S-transferase activity, monitored using 1-chloro-2,4-dinitrobenzene as the accepting substrate, was elevated in lung slices exposed to glucoraphanin. GSTα protein levels were increased by glucoraphanin and, to a much lesser extent, glucoerucin. It may be concluded that intact glucosinolates can modulate the activity of pulmonary carcinogen-metabolising enzyme systems, and can thus contribute to the documented chemopreventive activity of cruciferous vegetables in the lung.

Topics: Animals; Anticarcinogenic Agents; Cytochrome P-450 Enzyme System; Dealkylation; Glucose; Glucosinolates; Glutathione; Glutathione Transferase; Glycoside Hydrolases; Imidoesters; In Vitro Techniques; Isothiocyanates; Lung; Male; Metabolic Detoxication, Phase II; Oxazines; Oximes; Rats; Rats, Wistar; Sulfides; Sulfoxides; Thiocyanates; Up-Regulation

The potential of three isothiocyanates, namely R,S-sulforaphane, erucin and phenethyl isothiocyanate, of two naturally occurring glucosinolates, namely glucoerucin and glucoraphanin, and of the enantiomers of sulforaphane to modulate glucuronosyl transferase and epoxide hydrolase, two major carcinogen-metabolising enzyme systems, was investigated in precision-cut rat liver slices. Following exposure of the slices to the isothiocyanates (0-25 μM), erucin and phenethyl isothiocyanate, but not R,S-sulforaphane, elevated glucuronosyl transferase and epoxide hydrolase activities and expression, determined immunologically. Of the two enantiomers of sulforaphane, the R-enantiomer enhanced, whereas the S-enantiomer impaired, glucuronosyl transferase activity and only the former increased protein expression; furthermore, R-sulforaphane was more effective than the S-enantiomer in up-regulating microsomal epoxide hydrolase. When precision-cut rat liver slices were exposed to the same concentrations of glucoerucin and glucoraphanin, both glucosinolates caused a marked increase in the activity and expression of the microsomal epoxide hydrolase but had no effect on glucuronosyl transferase activity. It may be inferred that the ability of isothiocyanates to enhance hepatic microsomal epoxide hydrolase and glucuronosyl transferase activities is dependent on the nature of the side chain. Moreover, in the case of sulforaphane, the naturally occurring R-enantiomer increased both activities, whereas, in contrast, activities were impaired in the case of the S-enantiomer. Finally, intact glucosinolates are potent inducers of epoxide hydrolase and can thus contribute directly to the chemopreventive potential associated with cruciferous vegetable consumption.

Topics: Animals; Dose-Response Relationship, Drug; Enzyme Induction; Epoxide Hydrolases; Glucose; Glucosinolates; Glucuronosyltransferase; Imidoesters; Isothiocyanates; Liver; Male; Oximes; Rats; Rats, Wistar; Stereoisomerism; Sulfides; Sulfoxides; Thiocyanates

Increased consumption of cruciferous vegetables such as broccoli may reduce the risk of various cancers. Myrosinase is required to convert dietary glucosinolates from broccoli into bioactive isothiocyanates. We evaluated isothiocyanate excretion profiles in healthy subjects who consumed broccoli sprouts or broccoli supplement (no myrosinase) with equivalent glucosinolate content. Urinary metabolites of two major isothiocyanates, sulforaphane and erucin, were measured by liquid chromatography coupled with tandem mass spectrometry. Peak excretion of sulforaphane and erucin was higher and occurred sooner in subjects who consumed broccoli sprouts as compared to subjects who consumed the supplement. A subject-dependent shift in the ratio of urinary sulforaphane to erucin metabolites was observed in both groups, indicating conversion of sulforaphane to erucin. Lower histone deacetylase activity was observed in the peripheral blood mononuclear cells only in subjects consuming sprouts. Fresh broccoli sprouts differ from broccoli supplements in regards to excretion of isothiocyanates and bioactivity in human subjects.

Topics: Adult; Brassica; Diet; Dietary Supplements; Female; Glucose; Glucosinolates; Histone Deacetylases; Humans; Imidoesters; Isothiocyanates; Male; Middle Aged; Oximes; Plant Shoots; Sulfides; Sulfoxides; Thiocyanates