Accumulation of Sulforaphane and Alliin in Human Prostate Tissue.

Diets rich in cruciferous vegetables have been associated with a lower risk of incidence and progression of prostate cancer. Sulforaphane, an isothiocyanate derived from 4-methylsulphinylbutyl glucosinolate (glucoraphanin) that accumulates in certain of these vegetables, notably broccoli, has been implicated in their protective effects. Likewise, the consumption of garlic and its sulphur-containing compounds such as alliin have been associated with a reduction in risk of prostate cancer. In this study, we tested whether consuming glucoraphanin derived from broccoli seeds and alliin derived from garlic resulted in the occurrence of these potential bioactive compounds in the prostate, which may contribute to our understanding of the putative protective effects of these dietary components. We recruited 42 men scheduled for a trans-perineal prostate biopsy into a randomised, double-blinded, 2 × 2-factorial dietary supplement four-week intervention study, and 39 completed the study. The two active interventions were supplements providing glucoraphanin from broccoli (BroccoMax®) and alliin from garlic (Kwai Heartcare®). Following the intervention, prostate biopsy tissue was analysed for the presence of sulforaphane and its thiol conjugates and for alliin and associated metabolites. Sulforaphane occurred in significantly higher levels in the prostate tissue (both within the transition and peripheral zone) of men consuming the glucoraphanin containing supplements (p < 0.0001) compared to men not consuming these supplements. However, while alliin and alliin-derived metabolites were detected within the prostate, there was no significant difference in the concentrations of these compounds in the prostate of men consuming supplements derived from garlic compared to men not consuming these supplements.

Elevated CO2 improves glucosinolate metabolism and stimulates anticancer and anti-inflammatory properties of broccoli sprouts.

Sprouting process enhances plant bioactive compounds. Broccoli (Brassica oleracea L) sprouts are well known for their high levels of glucosinolates (GLs), amino acids, and antioxidants, which offer outstanding biological activities with positive impacts on plant metabolism. Elevated CO2 (eCO2, 620 ppm) was applied for 9 days to further improve nutritive and health-promoting values of three cultivars of broccoli sprouts i.e., Southern star, Prominence and Monotop. eCO2 improved sprouts growth and induced GLs accumulation e.g., glucoraphanin, possibly through amino acids production e.g., high methionine and tryptophan. There were increases in myrosinase activity, which stimulated GLs hydrolysis to yield health-promoting sulforaphane. Interestingly, low levels of ineffective sulforaphane nitrile were detected and positively correlated with reduced epithiospecifier protein after eCO2 treatment. High glucoraphanin and sulforaphane levels in eCO2 treated sprouts improved the anticarcinogenic and anti-inflammatory properties of their extracts. In conclusion, eCO2 treatment enriches broccoli sprouts with health-promoting metabolites and bioactivities.

Accumulation of Dietary S-Methyl Cysteine Sulfoxide in Human Prostate Tissue.

SCOPE: Observational studies have associated consumption of cruciferous vegetables with reduced risk of prostate cancer. This effect has been associated with the degradation products of glucosinolates-thioglycosides that accumulate within crucifers. The possible role of S-methyl cysteine sulfoxide, a metabolite that also accumulates in cruciferous vegetables, and its derivatives, in cancer prevention is relatively unexplored compared to glucosinolate derivatives. The hypothesis that consuming a broccoli soup results in the accumulation of sulfate (a SMCSO derivative) and other broccoli-derived metabolites in prostate tissue is tested. METHODS AND RESULTS: Eighteen men scheduled for transperineal prostate biopsy were recruited into a 4-week parallel single blinded diet supplementation study (NCT02821728). Nine men supplemented their diet with three 300 mL portions of a broccoli soup each week for four weeks prior to surgery. Analyses of prostate biopsy tissues reveal no detectable levels of glucosinolates and derivatives. In contrast, SMCSO is detected in prostate tissues of the participants, with significantly higher levels in tissue of men in the supplementation arm. SMCSO was also found in blood and urine samples from a previous intervention study with the identical broccoli soup. CONCLUSION: The consequences of SMCSO accumulation in prostate tissues and its potential role in prevention of prostate cancer remains to be investigated.

Long-Term Intake of Glucoraphanin-Enriched Kale Suppresses Skin Aging via Activating Nrf2 and the TßRII/Smad Pathway in SAMP1 Mice.

Sulforaphane, a potent antioxidant compound, is unstable at ambient temperature, whereas its precursor glucoraphanin is stable and metabolized to sulforaphane. Thus, we hypothesized that glucoraphanin-rich diet could effectively induce antioxidant enzyme activities and investigated the protective effects of long-term intake of a glucoraphanin-enriched kale (GEK) diet on skin aging in senescence-accelerated mouse prone 1 (SAMP1) mice. The senescence grading score was significantly lower after treatment with GEK for 39 weeks than that of the control mice. GEK also suppressed the thinning of the dorsal skin layer. Moreover, the GEK treatment enhanced the collagen production and increased the nuclear translocation of Nrf2 and HO-1 expression level in the skin tissue. TßRII and Smad3 expressions were clearly higher in the GEK-treated group than in the control group. Thus, GEK suppressed senescence in SAMP1 mice by enhancing the antioxidant activity and collagen production via the TßRII/Smad3 pathway, suggesting its practical applications for protection against skin aging.

Bioavailability of Sulforaphane Following Ingestion of Glucoraphanin-Rich Broccoli Sprout and Seed Extracts with Active Myrosinase: A Pilot Study of the Effects of Proton Pump Inhibitor Administration.

We examined whether gastric acidity would affect the activity of myrosinase, co-delivered with glucoraphanin (GR), to convert GR to sulforaphane (SF). A broccoli seed and sprout extract (BSE) rich in GR and active myrosinase was delivered before and after participants began taking the anti-acid omeprazole, a potent proton pump inhibitor. Gastric acidity appears to attenuate GR bioavailability, as evidenced by more SF and its metabolites being excreted after participants started taking omeprazole. Enteric coating enhanced conversion of GR to SF, perhaps by sparing myrosinase from the acidity of the stomach. There were negligible effects of age, sex, ethnicity, BMI, vegetable consumption, and bowel movement frequency and quality. Greater body mass correlated with reduced conversion efficiency. Changes in the expression of 20 genes in peripheral blood mononuclear cells were evaluated as possible pharmacodynamic indicators. When grouped by their primary functions based on a priori knowledge, expression of genes associated with inflammation decreased non-significantly, and those genes associated with cytoprotection, detoxification and antioxidant functions increased significantly with bioavailability. Using principal components analysis, component loadings of the changes in gene expression confirmed these groupings in a sensitivity analysis.

Overexpression of the MYB29 transcription factor affects aliphatic glucosinolate synthesis in Brassica oleracea.

KEY MESSAGE: Overexpression of BoMYB29 gene up-regulates the aliphatic glucosinolate pathway in Brassica oleracea plants increasing the production of the anti-cancer metabolite glucoraphanin, and the toxic and pungent sinigrin. Isothiocyanates, the bio-active hydrolysis products of glucosinolates, naturally produced by several Brassicaceae species, play an important role in human health and agriculture. This study aims at correlating the content of aliphatic glucosinolates to the expression of genes involved in their synthesis in Brassica oleracea, and perform functional analysis of BoMYB29 gene. To this purpose, three genotypes were used: a sprouting broccoli, a cabbage, and a wild genotype (Winspit), a high glucosinolate containing accession. Winspit showed the highest transcript level of BoMYB28, BoMYB29 and BoAOP2 genes, and BoAOP2 expression was positively correlated with that of the two MYB genes. Further analyses of the aliphatic glucosinolates also showed a positive correlation between the expression of BoAOP2 and the production of sinigrin and gluconapin in Winspit. The Winspit BoMYB29 CDS was cloned and overexpressed in Winspit and in the DH AG1012 line. Overexpressing Winspit plants produced higher quantities of alkenyl glucosinolates, such as sinigrin. Conversely, the DH AG1012 transformants showed a higher production of methylsulphinylalkyl glucosinolates, including glucoraphanin, and, despite an up-regulation of the aliphatic glucosinolate genes, no increase in alkenyl glucosinolates. The latter may be explained by the absence of a functional AOP2 gene in DH AG1012. Nevertheless, an extract of DH AG1012 lines overexpressing BoMYB29 provided a chemoprotective effect on human colon cells. This work exemplifies how the genetic diversity of B. oleracea may be used by breeders to select for higher expression of transcription factors for glucosinolate biosynthesis to improve its natural, health-promoting properties.

Isothiocyanate from Broccoli, Sulforaphane, and Its Properties.

Sulforaphane is an isothiocyanate occurring in stored form as glucoraphanin in cruciferous vegetables such as cabbage, cauliflower, and kale, and at high levels in broccoli especially in broccoli sprouts. Glucoraphanin requires the plant enzyme myrosinase for converting it into sulforaphane. Sulforaphane is metabolized through mercapturic acid pathway, being conjugated with glutathione and undergoes further biotransformation, yielding metabolites. Sulforaphane is extensively investigated and is in the interest in medicine for its health benefits. It has been shown that sulforaphane may protect against various types of cancer, may also decrease the risk of cardiovascular disease, and help in autism and osteoporosis. Our review offers a short summary of interesting properties of sulforaphane. Both the in vitro and in vivo methods/models and clinical studies are mentioned.

Chemopreventive glucosinolate accumulation in various broccoli and collard tissues: Microfluidic-based targeted transcriptomics for by-product valorization.

Floret, leaf, and root tissues were harvested from broccoli and collard cultivars and extracted to determine their glucosinolate and hydrolysis product profiles using high performance liquid chromatography and gas chromotography. Quinone reductase inducing bioactivity, an estimate of anti-cancer chemopreventive potential, of the extracts was measured using a hepa1c1c7 murine cell line. Extracts from root tissues were significantly different from other tissues and contained high levels of gluconasturtiin and glucoerucin. Targeted gene expression analysis on glucosinolate biosynthesis revealed that broccoli root tissue has elevated gene expression of AOP2 and low expression of FMOGS-OX homologs, essentially the opposite of what was observed in broccoli florets, which accumulated high levels of glucoraphanin. Broccoli floret tissue has significantly higher nitrile formation (%) and epithionitrile specifier protein gene expression than other tissues. This study provides basic information of the glucosinolate metabolome and transcriptome for various tissues of Brassica oleracea that maybe utilized as potential byproducts for the nutraceutical market.

Optimization of pulsed electric field pre-treatments to enhance health-promoting glucosinolates in broccoli flowers and stalk.

BACKGROUND: The effect of pulsed electric field (PEF) treatment variables (electric field strength and treatment time) on the glucosinolate content of broccoli flowers and stalks was evaluated. Samples were subjected to electric field strengths from 1 to 4 kV cm(-1) and treatment times from 50 to 1000 µs at 5 Hz. RESULTS: Data fitted significantly (P < 0.0014) the proposed second-order response functions. The results showed that PEF combined treatment conditions of 4 kV cm(-1) for 525 and 1000 µs were optimal to maximize glucosinolate levels in broccoli flowers (ranging from 187.1 to 212.5%) and stalks (ranging from 110.6 to 203.0%) respectively. The predicted values from the developed quadratic polynomial equation were in close agreement with the actual experimental values, with low average mean deviations (E%) ranging from 0.59 to 8.80%. CONCLUSION: The use of PEF processing at moderate conditions could be a suitable method to stimulate production of broccoli with high health-promoting glucosinolate content.

Isothiocyanate metabolism, distribution, and interconversion in mice following consumption of thermally processed broccoli sprouts or purified sulforaphane.

SCOPE: 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. METHODS AND RESULTS: 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. CONCLUSION: 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.

A new ultra-rapid UHPLC/MS/MS method for assessing glucoraphanin and sulforaphane bioavailability in human urine.

Sulforaphane (SFN) is the product of the enzymatic hydrolysis of glucoraphanin (GR), the main glucosinolate present in broccoli sprouts. The beneficial actions attributed to SFN are mainly supported by in dietary study not clear. Surely the panellists ate more than just the broccoli portion - please clarify vitro experiments; further in vivo assays are necessary to analyse the described biological actions in humans. A new ultra-fast, accurate, robust, and selective UHPLC/MS/MS procedure (2-min chromatogram; >87% recovery; LOQ and LOD of 20-156 and 4-20nmol L(-1), respectively; and intra- and inter-day variations lower than 10%) was used for the simultaneous determination of GR and SFN in human urine. The analytical capacity of this novel method was further tested by determining the bioavailability of GR and its metabolic derivatives in urine from volunteers after the consumption of ½ and 1 servings of broccoli sprouts (30 and 60g, respectively). Bioavailability values for SFN of up to 40% after a single intake of both ½ and 1 servings showed the suitability of the new method for the determination of exogenous metabolites following dietary interventions.

Pre-harvest methyl jasmonate treatment enhances cauliflower chemoprotective attributes without a loss in postharvest quality.

Methyl jasmonate (MeJA) treatment can significantly increase glucosinolate (GS) concentrations in Brassica vegetables and potentially enhance anticancer bioactivity. Although MeJA treatment may promote ethylene biosynthesis, which can be detrimental to postharvest quality, there are no previous reports of its effect on cauliflower postharvest quality. To address this, cauliflower curds in field plots were sprayed with either 0.1 % Triton X-100 (control) or 500 µM MeJA solutions four days prior to harvest, then stored at 4 °C. Tissue subsamples were collected after 0, 10, 20, and 30 days of postharvest storage and assayed for visual color change, ethylene production, GS concentrations, and extract quinone reductase inductive activity. MeJA treatment increased curd GS concentrations of glucoraphanin, glucobrassicin, and neoglucobrassicin by 1.5, 2.4, and 4.6-fold over controls, respectively. MeJA treated cauliflower showed significantly higher quinone reductase activity, a biomarker for anticancer bioactivity, without reducing visual color and postharvest quality for 10 days at 4 °C storage.

Lactic acid bacteria convert glucosinolates to nitriles efficiently yet differently from enterobacteriaceae.

Glucosinolates from the genus Brassica can be converted into bioactive compounds known to induce phase II enzymes, which may decrease the risk of cancers. Conversion via hydrolysis is usually by the brassica enzyme myrosinase, which can be inactivated by cooking or storage. We examined the potential of three beneficial bacteria, Lactobacillus plantarum KW30, Lactococcus lactis subsp. lactis KF147, and Escherichia coli Nissle 1917, and known myrosinase-producer Enterobacter cloacae to catalyze the conversion of glucosinolates in broccoli extract. Enterobacteriaceae consumed on average 65% glucoiberin and 78% glucoraphanin, transforming them into glucoiberverin and glucoerucin, respectively, and small amounts of iberverin nitrile and erucin nitrile. The lactic acid bacteria did not accumulate reduced glucosinolates, consuming all at 30-33% and transforming these into iberverin nitrile, erucin nitrile, sulforaphane nitrile, and further unidentified metabolites. Adding beneficial bacteria to a glucosinolate-rich diet may increase glucosinolate transformation, thereby increasing host exposure to bioactives.

Physiological and biochemical metabolism of germinating broccoli seeds and sprouts.

Changes in physiological and biochemical metabolism as well as glucoraphanin and sulforaphane contents of germinating broccoli seeds and sprouts were investigated in this study. Sprout length, root length, and fresh weight increased with germination time. Dry weight varied from 2.5 to 3.0 mg per sprout. A rapid increase in respiratory rate of sprouts occurred between 24 and 36 h of germination and then stayed at a high level. HPLC analysis found that glucoraphanin content increased at the early stage (0-12 h) of germination, decreased to a low value of 3.02 mg/g at 48 h, and then reached the highest value of 6.30 mg/g at 72 h of germination. Sulforaphane content decreased dramatically during the first day of germination, then increased slowly, and reached a high value of 3.38 mg/g at 48 h before declining again.

Comparison of isothiocyanate metabolite levels and histone deacetylase activity in human subjects consuming broccoli sprouts or broccoli supplement.

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.

Dietary glucoraphanin-rich broccoli sprout extracts protect against UV radiation-induced skin carcinogenesis in SKH-1 hairless mice.

Feeding broccoli sprout extracts providing daily doses of 10 micromol of glucoraphanin to SKH-1 hairless mice with prior chronic exposure to UV radiation (30 mJ cm(-2) of UVB, twice a week, for 17 weeks) inhibited the development of skin tumors during the subsequent 13 weeks; compared to the controls, tumor incidence, multiplicity, and volume were reduced by 25, 47, and 70%, respectively, in the animals that received the protective agent.

Mucoadhesive thiolated chitosans as platforms for oral controlled drug delivery: synthesis and in vitro evaluation.

The aim of the present study was to evaluate the influence of the degree of modification and the polymer chain length on the mucoadhesive properties and the swelling behavior of thiolated chitosan derivatives obtained via a simple one-step reaction between the polymer and 2-iminothiolane. The conjugates differing in molecular mass of the polymer backbone and in the amount of immobilized thiol groups were compressed into tablets. They were investigated for their mucoadhesive properties on freshly excised porcine mucosa via tensile studies and the rotating cylinder method. Moreover, the swelling behavior of these tablets in aqueous solutions was studied by a simple gravimetric method. The obtained results demonstrated that the total work of adhesion of chitosan-TBA (=4-thio-butyl-amidine) conjugates can be improved by an increasing number of covalently attached thiol groups; a 100-fold increase compared to unmodified chitosan was observed for a medium molecular mass chitosan-TBA conjugate exhibiting 264 microM thiol groups per gram polymer. Also, the polymer chain length had an influence on the mucoadhesive properties of the polymer. The medium molecular mass polymer displayed a fourfold improved adhesion on the rotating cylinder compared to the derivative of low molecular mass. These results contribute to the development of new delivery systems exhibiting improved mucoadhesive properties.