The rodent model of impaired gastric motility induced by allyl isothiocyanate, a pungent ingredient of wasabi, to evaluate therapeutic agents for functional dyspepsia

Functional dyspepsia (FD) is thought to be mainly based on gastric motility dysfunction and chronic hypersensitivity, yet FD animal models has been reported a few. We studied to establish the mouse model of impaired gastric motility induced by a pungent ingredient of wasabi allyl isothiocyanate (AITC), which is reliable to evaluate prokinetic agents. Male ddY mice were used. Gastric motility was measured by 13C-acetic acid breath test in conscious mice. AITC (80 mM) was given 60 min before the measurement of motility. Prokinetic agents including itopride (30, 100 mg/kg), mosapride (0.1-1 mg/kg), neostigmine (30 μg/kg), acotiamide (10-100 mg/kg), and daikenchuto (100-1000 mg/kg) were given 40 min before the measurement. AITC impaired gastric motility without mucosal damages, which reverted 24 h after AITC treatment. The decreased motility induced by AITC was restored by prokinetic agents such as itopride, mosapride, neostigmine, and acotiamide. In separate experiment, daikenchuto recovered the decreased motility induced by AITC, although daikenchuto had no effect on motility in normal condition. In conclusion, it is considered that the AITC-induced impaired gastric motility mouse model is useful to develop new prokinetic agents for treatment of FD, and to re-evaluate traditional Japanese herbal medicines.

Molecular Mechanisms of the Anti-Cancer Effects of Isothiocyanates from Cruciferous Vegetables in Bladder Cancer

Bladder cancer (BC) is a representative of urological cancer with a high recurrence and metastasis potential. Currently, cisplatin-based chemotherapy and immune checkpoint inhibitors are used as standard therapy in patients with advanced/metastatic BC. However, these therapies often show severe adverse events, and prolongation of survival is unsatisfactory. Therefore, a treatment strategy using natural compounds is of great interest. In this review, we focused on the anti-cancer effects of isothiocyanates (ITCs) derived from cruciferous vegetables, which are widely cultivated and consumed in many regions worldwide. Specifically, we discuss the anti-cancer effects of four ITC compounds—allyl isothiocyanate, benzyl isothiocyanate, sulforaphane, and phenethyl isothiocyanate—in BC; the molecular mechanisms underlying their anti-cancer effects; current trends and future direction of ITC-based treatment strategies; and the carcinogenic potential of ITCs. We also discuss the advantages and limitations of each ITC in BC treatment, furthering the consideration of ITCs in treatment strategies and for improving the prognosis of patients with BC.

Hydrogen Sulfide (H₂S) Releasing Capacity of Isothiocyanates from Moringa oleifera Lam

Moringa oleifera Lam. is rich in phytochemical compounds especially glucosinolates (GSs) and isothiocyanates (ITCs), which are active compounds for cancer chemoprevention benefits of Brassicaceae vegetables. In this study, we determined the total contents of GSs and ITCs and their specific profiles in different Moringa tissues including seeds, stems, leaves and roots. Seeds (seeds with shell and seed kernel) showed significantly higher levels of total GSs and ITCs than that of other Moringa tissues. The hydrogen sulfide (H₂S) releasing capacity of total ITCs extracted from different Moringa tissues was determined by lead (II) acetate assay in 24-well plates. The H₂S releasing capacity of different Moringa tissues were evaluated and compared. Moringa seeds showed the highest H₂S releasing capacity, followed by roots, leaves and stems. Our results suggest that Moringa based foods may exhibit health benefits due to its GSs and ITCs contents that are the precursors for H₂S, in addition to the recognized action mechanisms of ITCs.

Potential effects of sulforaphane to fight obesity

Obesity is linked to the onset of many diseases such as diabetes mellitus, cardiovascular diseases and cancer, among others. The prevalence of obesity nearly doubled worldwide between 1980 and 2014. Simultaneously, in the last decade, the effects of sulforaphane as a potential treatment for obesity have been investigated, with promising results. Fruits and vegetables and their processed agri-food co-products are good sources of natural health-promoting compounds. Brassica crops are among the most produced crops in the world and are a good source of glucoraphanin, which, following hydrolysis, releases sulforaphane. The Brassicaceae family generates large amounts of co-products with no intended use, causing negative economic and environmental impact. Valorization of these co-products could be achieved through their exploitation for the extraction of bioactive compounds such as sulforaphane. However, the extraction process still needs further improvement for its economic feasibility. This article reviews the potential effects of sulforaphane in the treatment of obesity, linked to the relevance of giving Brassica co-products added value, which is of key importance for the competitiveness of farmers and the agri-food industry. © 2018 Society of Chemical Industry.

Targeting Colorectal Cancer Proliferation, Stemness and Metastatic Potential Using Brassicaceae Extracts Enriched in Isothiocyanates: A 3D Cell Model-Based Study

Colorectal cancer (CRC) recurrence is often attributable to circulating tumor cells and/or cancer stem cells (CSCs) that resist to conventional therapies and foster tumor progression. Isothiocyanates (ITCs) derived from Brassicaceae vegetables have demonstrated anticancer effects in CRC, however little is known about their effect in CSCs and tumor initiation properties. Here we examined the effect of ITCs-enriched Brassicaceae extracts derived from watercress and broccoli in cell proliferation, CSC phenotype and metastasis using a previously developed three-dimensional HT29 cell model with CSC-like traits. Both extracts were phytochemically characterized and their antiproliferative effect in HT29 monolayers was explored. Next, we performed cell proliferation assays and flow cytometry analysis in HT29 spheroids treated with watercress and broccoli extracts and respective main ITCs, phenethyl isothiocyanate (PEITC) and sulforaphane (SFN). Soft agar assays and relative quantitative expression analysis of stemness markers and Wnt/β-catenin signaling players were performed to evaluate the effect of these phytochemicals in stemness and metastasis. Our results showed that both Brassicaceae extracts and ITCs exert antiproliferative effects in HT29 spheroids, arresting cell cycle at G₂/M, possibly due to ITC-induced DNA damage. Colony formation and expression of LGR5 and CD133 cancer stemness markers were significantly reduced. Only watercress extract and PEITC decreased ALDH1 activity in a dose-dependent manner, as well as β-catenin expression. Our research provides new insights on CRC therapy using ITC-enriched Brassicaceae extracts, specially watercress extract, to target CSCs and circulating tumor cells by impairing cell proliferation, ALDH1-mediated chemo-resistance, anoikis evasion, self-renewal and metastatic potential.

HPLC Separation of Sulforaphane Enantiomers in Broccoli and Its Sprouts by Transformation into Diastereoisomers Using Derivatization with (S)-Leucine

Racemic sulforaphane, which was derivatized with (S)-leucine (l-leucine), was resolved by reversed phase HPLC with UV detection. The optimum mobile phase conditions were found to be 10 mM citric acid (pH 2.8) containing 22% methanol at 35 °C using detection at 254 nm. Sulforaphane enantiomers in florets and stems of five brands of broccoli and leaves and stems of three brands of broccoli sprouts were analyzed by the proposed HPLC method. Both sulforaphane enantiomers were detected in all of the samples. The S/R ratios of sulforaphane in broccoli samples were 1.5-2.6/97.4-98.5% for florets and 5.0-12.1/87.9-95.0% for stems. The S/R ratios in broccoli sprout samples were higher than those in broccoli samples and were found to be 8.3-19.7/80.3-91.7% for leaves and 37.0-41.8/58.2-63.0% for stems. (S)-Sulforaphane detected in the broccoli and its sprout samples was positively identified by separately using an HPLC with a chiral column (Chiralpak AD-RH) and mass spectrometry.

Inhibition of growth and induction of apoptosis in A549 cells by compounds from oxheart cabbage extract

BACKGROUND

Oxheart cabbage (Brassica oleracea var. capitata) is a member of the Brassica genus. Although some studies on the anticancer effects of extracts from oxheart cabbage have been reported, comprehensive information on the bioactive fractions and components from oxheart cabbage extracts is still lacking. The aim of this study was to isolate and identify the bioactive fractions and components from oxheart cabbage seeds using activity-guided isolation methods.

RESULTS

The cytotoxicity and apoptotic effects of fraction II, fraction III, iberverin, sulforaphane and iberin from oxheart cabbage seed extract were investigated. The results showed that all five components had inhibitory effects on the in vitro growth of A549 cells which were dose-dependent. These compounds also changed the morphology of A549 cells, and their inhibitory activity on A549 cells was as follows: sulforaphane > iberin > iberverin > fraction III > fraction II. The IC50 values were 3.53 ± 0.63, 4.93 ± 1.02, 7.07 ± 0.51, 15.56 ± 0.24 and 27.32 ± 0.63 µg mL(-1) respectively. Fraction II, fraction III, iberverin, sulforaphane and iberin induced cell apoptosis by increasing early apoptosis and late apoptosis/necrosis, and activation of caspase-3, -8 and -9.

CONCLUSION

These results indicated that the decrease in A549 cell viability by active compounds from oxheart cabbage seed extract was due to the induction of apoptosis. © 2015 Society of Chemical Industry.

The Chemopreventive Phytochemical Moringin Isolated from Moringa oleifera Seeds Inhibits JAK/STAT Signaling

Sulforaphane (SFN) and moringin (GMG-ITC) are edible isothiocyanates present as glucosinolate precursors in cruciferous vegetables and in the plant Moringa oleifera respectively, and recognized for their chemopreventive and medicinal properties. In contrast to the well-studied SFN, little is known about the molecular pathways targeted by GMG-ITC. We investigated the ability of GMG-ITC to inhibit essential signaling pathways that are frequently upregulated in cancer and immune disorders, such as JAK/STAT and NF-κB. We report for the first time that, similarly to SFN, GMG-ITC in the nanomolar range suppresses IL-3-induced expression of STAT5 target genes. GMG-ITC, like SFN, does not inhibit STAT5 phosphorylation, suggesting a downstream inhibitory event. Interestingly, treatment with GMG-ITC or SFN had a limited inhibitory effect on IFNα-induced STAT1 and STAT2 activity, indicating that both isothiocyanates differentially target JAK/STAT signaling pathways. Furthermore, we showed that GMG-ITC in the micromolar range is a more potent inhibitor of TNF-induced NF-κB activity than SFN. Finally, using a cellular system mimicking constitutive active STAT5-induced cell transformation, we demonstrated that SFN can reverse the survival and growth advantage mediated by oncogenic STAT5 and triggers cell death, therefore providing experimental evidence of a cancer chemopreventive activity of SFN. This work thus identified STAT5, and to a lesser extent STAT1/STAT2, as novel targets of moringin. It also contributes to a better understanding of the biological activities of the dietary isothiocyanates GMG-ITC and SFN and further supports their apparent beneficial role in the prevention of chronic illnesses such as cancer, inflammatory diseases and immune disorders.

Effects of Brassicaceae Isothiocyanates on Prostate Cancer

Despite the major progress made in the field of cancer biology, cancer is still one of the leading causes of mortality, and prostate cancer (PCa) is one of the most encountered malignancies among men. The effective management of this disease requires developing better anticancer agents with greater efficacy and fewer side effects. Nature is a large source for the development of chemotherapeutic agents, with more than 50% of current anticancer drugs being of natural origin. Isothiocyanates (ITCs) are degradation products from glucosinolates that are present in members of the family Brassicaceae. Although they are known for a variety of therapeutic effects, including antioxidant, immunostimulatory, anti-inflammatory, antiviral and antibacterial properties, nowadays, cell line and animal studies have additionally indicated the chemopreventive action without causing toxic side effects of ITCs. In this way, they can induce cell cycle arrest, activate apoptosis pathways, increase the sensitivity of resistant PCa to available chemodrugs, modulate epigenetic changes and downregulate activated signaling pathways, resulting in the inhibition of cell proliferation, progression and invasion-metastasis. The present review summarizes the chemopreventive role of ITCs with a particular emphasis on specific molecular targets and epigenetic alterations in in vitro and in vivo cancer animal models.

Sulforaphane-rich broccoli sprout extract improves hepatic abnormalities in male subjects

AIM: To evaluate effects of dietary supplementation of sulforaphane (SF)-rich broccoli sprout (BS) extract on hepatic abnormalities in Japanese male participants.

METHODS: In a randomized, placebo-controlled, double blind trial, male participants with fatty liver received either BS capsules containing glucoraphanin [GR; a precursor of SF (n = 24)] or placebo (n = 28) for 2 mo. Liver function markers, serum levels of aspartate and alanine aminotransferases (AST and ALT, respectively) and γ-glutamyl transpeptidase (γ-GTP) and an oxidative stress marker, urinary levels of 8-hydroxydeoxyguanosine (8-OHdG), were measured and compared in participants before and after the trial period. In an animal model, chronic liver failure was induced in Sprague-Dawley rats by successive intraperitoneal injection with N-nitrosodimethylamine (NDMA) for 4 wk. Concomitantly, rats received AIN-76 diets supplemented with or without BS extract. Thereafter, rats were sacrificed, and their sera and livers were collected to measure serum liver function markers and hepatic levels of thiobarbituric acid reactive substances (TBARS) levels and hepatic glutathione S-transferase (GST) activity, a prototypical phase 2 antioxidant enzyme.

RESULTS: Dietary supplementation with BS extract containing SF precursor GR for 2 mo significantly decreased serum levels of liver function markers, ALT [median (interquartile range), before: 54.0 (34.5-79.0) vs after supplementation: 48.5 (33.3-65.3) IU/L, P < 0.05] and γ-GTP [before: 51.5 (40.8-91.3) vs after: 50.0 (37.8-85.3) IU/L, P < 0.05], as well as the alkali phosphatase activity. Placebo showed no significant effects on the markers. The urinary level of 8-OHdG, an established oxidative stress marker, was significantly reduced in participants who had received BS capsules but not the placebo [before: 6.66 (5.51-9.03) vs after: 5.49 (4.89-6.66) ng/mg-creatinine, P < 0.05]. The reduction of urinary 8-OHdG was significantly correlated with decreased levels of both ALT and γ-GTP [∆8-OHdG and ∆ALT: Spearman r (r) 0.514 and P = 0.012, ∆8-OHdG and ∆γ-GTP: r = 0.496 and P = 0.016]. Intake of BS extract prevented NDMA-induced chronic liver failure in rats, which was attributable to the suppression of the increase in TBARS through induction of hepatic phase 2 antioxidant enzymes including hepatic GST (86.6 ± 95.2 vs 107.8 ± 7.7 IU/g, P < 0.01).

CONCLUSION: Dietary supplementation with BS extract containing the SF precursor GR is likely to be highly effective in improving liver function through reduction of oxidative stress.

Taste detection of the non-volatile isothiocyanate moringin results in deterrence to glucosinolate-adapted insect larvae

Isothiocyanates (ITCs), released from Brassicales plants after hydrolysis of glucosinolates, are known for their negative effects on herbivores but mechanisms have been elusive. The ITCs are initially present in dissolved form at the site of herbivore feeding, but volatile ITCs may subsequently enter the gas phase and all ITCs may react with matrix components. Deterrence to herbivores resulting from topically applied volatile ITCs in artificial feeding assays may hence lead to ambiguous conclusions. In the present study, the non-volatile ITC moringin (4-(α-L-rhamnopyranosyloxy)benzyl ITC) and its glucosinolate precursor glucomoringin were examined for effects on behaviour and taste physiology of specialist insect herbivores of Brassicales. In feeding bioassays, glucomoringin was not deterrent to larvae of Pieris napi (Lepidoptera: Pieridae) and Athalia rosae (Hymenoptera: Tenthredinidae), which are adapted to glucosinolates. Glucomoringin stimulated feeding of larvae of the related Pieris brassicae (Lepidoptera: Pieridae) and also elicited electrophysiological activity from a glucosinolate-sensitive gustatory neuron in the lateral maxillary taste sensilla. In contrast, the ITC moringin was deterrent to P. napi and P. brassicae at high levels and to A. rosae at both high and low levels when topically applied to cabbage leaf discs (either 12, 120 or 1200 nmol moringin per leaf disc of 1cm diameter). Survival of A. rosae was also significantly reduced when larvae were kept on leaves treated with moringin for several days. Furthermore, moringin elicited electrophysiological activity in a deterrent-sensitive neuron in the medial maxillary taste sensillum of P. brassicae, providing a sensory mechanism for the deterrence and the first known ITC taste response of an insect. In simulated feeding assays, recovery of moringin was high, in accordance with its non-volatile nature. Our results demonstrate taste-mediated deterrence of a non-volatile, natural ITC to glucosinolate-adapted insects.

Antimalarial Isocyano and Isothiocyanato Sesquiterpenes with Tri- and Bicyclic Skeletons from the Nudibranch Phyllidia ocellata

Five new isocyano/isothiocyanato sesquiterpenes (1-5) with tri- or bicyclic carbon skeletons have been characterized from Australian specimens of the nudibranch Phyllidia ocellata. Spectroscopic analyses at 900 MHz were informed by DFT calculations. The 1S, 5S, 8R configuration of 2-isocyanoclovene (1) was determined by X-ray crystallographic analysis of formamide 6. A biosynthetic pathway to clovanes 1 and 2 from epicaryolane precursors is proposed. Isocyanides 1, 2, and 4 showed activity against Plasmodium falciparum (IC50 0.26-0.30 μM), while isothiocyanate 3 and formamide 6 had IC50 values of >10 μM.

Preparation and characterization of inclusion complex of benzyl isothiocyanate extracted from papaya seed with β-cyclodextrin

The inclusion complex of benzyl isothiocyanate (BITC), extracted from papaya seed with β-cyclodextrin (β-CD), was prepared. Different analytical techniques, such as Fourier transform infrared spectroscopy, thermal analysis, X-ray diffractometry, particle size distribution analysis and (1)H Nuclear magnetic resonance analysis, were used to investigate the characterization of the inclusion complex (BITC-β-CD). All these approaches indicated that the inclusion complex was capable of being formed. The inclusion complex exhibited different spectroscopic and thermodynamic features and properties from BITC, and we deduced the possible inclusion modes for BITC-β-CD. The calculated apparent stability constant of the BITC-β-CD was 600.8l/mol, and the aqueous solubility of BITC was indistinctively improved by phase solubility studies. The results illustrated that β-CD was a proper excipient for increasing the stability and controlled release of BITC. Thus, β-CD complexation technology would be a promising approach, in expanding the application of BITC as a food antibacterial agent.

Direct and indirect antioxidant activity of polyphenol- and isothiocyanate-enriched fractions from Moringa oleifera

Moringa oleifera Lam. is a fast-growing, tropical tree with various edible parts used as nutritious food and traditional medicine. This study describes an efficient preparatory strategy to extract and fractionate moringa leaves by fast centrifugal partition chromatography (FCPC) to produce polyphenol and isothiocyanate (ITC) rich fractions. Characterization and further purification of these fractions showed that moringa polyphenols were potent direct antioxidants assayed by oxygen radical absorbance capacity (ORAC), whereas moringa ITCs were effective indirect antioxidants assayed by induction of NAD(P)H quinone oxidoreductase 1 (NQO1) activity in Hepa1c1c7 cells. In addition, purified 4-[(α-l-rhamnosyloxy)benzyl]isothiocyanate and 4-[(4'-O-acetyl-α-l-rhamnosyloxy)benzyl]isothiocyanate were further evaluated for their ORAC and NQO1 inducer potency in comparison with sulforaphane (SF). Both ITCs were as potent as SF in inducing NQO1 activity. These findings suggest that moringa leaves contain a potent mixture of direct and indirect antioxidants that can explain its various health-promoting effects.

Isolation and identification of 4-α-rhamnosyloxy benzyl glucosinolate in Noccaea caerulescens showing intraspecific variation

Glucosinolates are secondary plant compounds typically found in members of the Brassicaceae and a few other plant families. Usually each plant species contains a specific subset of the ∼ 130 different glucosinolates identified to date. However, intraspecific variation in glucosinolate profiles is commonly found. Sinalbin (4-hydroxybenzyl glucosinolate) so far has been identified as the main glucosinolate of the heavy metal accumulating plant species Noccaea caerulescens (Brassicaceae). However, a screening of 13 N. caerulescens populations revealed that in 10 populations a structurally related glucosinolate was found as the major component. Based on nuclear magnetic resonance (NMR) and mass spectrometry analyses of the intact glucosinolate as well as of the products formed after enzymatic conversion by sulfatase or myrosinase, this compound was identified as 4-α-rhamnosyloxy benzyl glucosinolate (glucomoringin). So far, glucomoringin had only been reported as the main glucosinolate of Moringa spp. (Moringaceae) which are tropical tree species. There was no apparent relation between the level of soil pollution at the location of origin, and the presence of glucomoringin. The isothiocyanate that is formed after conversion of glucomoringin is a potent antimicrobial and antitumor agent. It has yet to be established whether glucomoringin or its breakdown product have an added benefit to the plant in its natural habitat.

Inhibition of cytochrome P450 2C9 expression and activity in vitro by allyl isothiocyanate

The growing interest in the use of natural herbal products and dietary supplements to treat and prevent diseases raises the question of medicinal drug safety. Allyl isothiocyanate, a hydrolysis product of a glucosinolate, sinigrin, has multiple beneficial properties, and based on this fact, allyl isothiocyanate-containing dietary supplements have been developed. To date, no studies of the effects of this compound on the cytochrome P450 2C9 have been reported. In this study, we found that allyl isothiocyanate reduced catalytic activity, messenger ribonucleic acid, and protein expression of cytochrome P450 2C9 in HepaRG cells. An investigation of the transcriptional activity of the pregnane X receptor and the constitutive androstane receptor revealed that allyl isothiocyanate disrupted the transcriptional coregulation effects of the pregnane X receptor/constitutive androstane receptor with several important coregulators and interfered with the assembly of transcriptional complexes of the cytochrome P450 2C9 pregnane X receptor/constitutive androstane receptor-response element. The decrease of cytochrome P450 2C9 expression and activity mediated by allyl isothiocyanate suggested that this agent could alter the metabolism of drugs metabolized by cytochrome P450 2C9. This may cause food/dietary supplement-drug interactions or alter the therapeutic effects, and even the toxicity of drugs coadministered with allyl isothiocyanate. Since the consumption of allyl isothiocyanate-containing food/dietary supplements continues to increase, it is important to predict and ultimately avoid interactions with concomitant drugs. It is required that these possible pharmacokinetic interactions be characterized and the recommendations available to patients and healthcare professionals be improved.

Cytotoxic effect of Reseda lutea L.: A case of forgotten remedy

ETHNOPHARMACOLOGICAL RELEVANCE

Reseda lutea L. (Resedaceae) or Wild Mignonette is a widely distributed plant species. Pliny the Elder (AD 23-AD 79), a Roman scholar and naturalist, reported the use of R. lutea for reducing tumors in his Historia naturalis. Accounts of the beneficial effects of R. lutea in tumor treatment could also be found in the works of later authors, such as Étienne François Geoffroy (1672-1731) and Samuel Frederick Gray (1766-1828). However, to date no in vivo or in vitro evidence exists in support of the alleged tumor healing properties of R. lutea.

MATERIALS AND METHODS

The composition of autolysates obtained from different organs (root, flower and fruit) of R. lutea was investigated by GC and GC-MS analyses and IR, 1D and 2D NMR spectroscopy. These analyses led to the discovery of a new compound isolated in pure form from the flower autolysate. Autolysates and their major constituents were submitted to MTT-dye reduction cytotoxic assay on human A375 (melanoma) and MRC5 (fibroblast) cell lines. Mechanism of the cytotoxic effects was studied by cell cycle analysis and Annexin V assay.

RESULTS

Benzyl isothiocyanate and 2-(α-l-rhamnopyranosyloxy)benzyl isothiocyanate were identified as the major constituents of the root and flower autolysates, respectively (the later represents a new natural product). These compounds showed significant antiproliferative effects against both cell lines, which could also explain the observed high cytotoxic activity of the tested autolysates. Cell cycle analysis revealed apoptosis as the probable mechanism of cell death.

CONCLUSIONS

Tumor healing properties attributed to R. lutea in the pre-modern texts were substantiated by the herein obtained results. Two isothiocyanates were found to be the major carriers of the observed activity. Although there was a relatively low differential effect of the plant metabolites on transformed and non-transformed cell lines, one can argue that the noted strong cytotoxicity provides first evidence that could explain the long forgotten use of this particular species.

Simultaneous determination of sulphoraphane and sulphoraphane nitrile in Brassica vegetables using ultra-performance liquid chromatography with tandem mass spectrometry

INTRODUCTION

Several analytical methods exist for the determination of sulphoraphane or sulphoraphane nitrile from biological matrices and plant extracts. However, no UPLC-MS/MS method exists for the simultaneous detection of both.

OBJECTIVE

To develop and validate an UPLC-MS/MS method for the simultaneous analysis of sulphoraphane and sulphoraphane nitrile from Brassica oleracea L. ssp. italica

METHODS

This method was developed utilising an Acquity BEH C8 column with gradient elution combined with tandem mass spectrometry, using positive electrospray ionisation in multiple reaction monitoring mode.

RESULTS

The retention times for sulphoraphane and sulphoraphane nitrile were 0.4 and 0.6 min respectively, and total run time was 3 min. The method was validated for linearity, sensitivity, precision, accuracy, matrix effects and recovery. The method was employed to determine glucoraphanin hydrolysis products in broccoli and the predominant product was found to vary depending on the variety tested. It was also applied to the accurate determination of sulphoraphane and sulphoraphane nitrile in broccoli samples hydrolysed under different conditions. It was observed that the formation of sulphoraphane and sulphoraphane nitrile was influenced by the temperature of the reaction.

CONCLUSION

The validated UPLC-MS/MS method for simultaneous detection of sulphoraphane and sulphoraphane nitrile was shown to be applicable to broccoli plants and is expected to be applicable to other cruciferous sources.

SPE for the simultaneous determination of various isothiocyanates

Several SPE sorbents were investigated for the extraction of a group of chemically diverse isothiocyanates (ITCs). They included bonded silica, carbon-based, and polymer-based sorbents with various functional groups. Results showed large differences in the ability of these sorbents to simultaneously extract ITCs from standard solutions. Recovery rates were on average the highest with divinylbenzene (DVB) based polymeric sorbents, especially with a DVB/N-vinylpyrrolidone copolymer that had recovery rates ranging between 86.7 and 95.6%. These sorbents achieved the most balanced extraction efficiency between aliphatic and aromatic, polar, and nonpolar ITCs. With graphitized carbon, C(18)-bonded silica, and amide-containing sorbent, recovery levels were higher for the two least polar aromatic ITCs (benzyl ITC and phenylethyl ITC), whereas for the polar aliphatic ITCs levels were the lowest. The least retained one, was methyl ITC that is the most polar with recoveries between 0 and 31.5%. The presence of amide groups, especially in a polyamide sorbent, appeared to be particularly unsuitable for the extraction of aliphatic ITCs. A copolymer made up of DVB and N-vinylpyrrolidone was therefore shown to be the most suited for the extraction of both aliphatic and aromatic ITCs.

Extraction and identification of isothiocyanates from broccolini seeds

Broccolini (Brassica oleracea Italica x Alboglabra) is a cross between broccoli and kai-lan (Chinese broccoli), which contains abundant glucosinolates. The intact glucosinolates are believed to be inactive, while their hydrolysis products, such as isothiocyanates (ITCs), are found to have bacteriocidal and anticarcinogenic activities. So far, no report is available about generation of ITCs during the process of glucosinolate hydrolysis in broccolini. In this study, the hydrolysis of broccolini seed glucosinolates was investigated under controlled conditions of pH, time and temperature, and the ITCs produced were determined. The results showed that an optimum hydrolysis of glucosinolates could be achieved at a temperature of 250C, at pH 7.0, and a reaction time of eight hours. Furthermore, GC-MS analysis indicated that the extracted ITCs primarily were: 3-BITC (3-benzyl-ITC) (10.8%), 4-methylpentyl-ITC (0.5%), 1-isothiocyanato-butane (26.8%), PEITC (phenethyl-ITC) (22.6%) and SFN (sulforaphane) (19.2%).

Potential skin antiinflammatory effects of 4-methylthiobutylisothiocyanate (MTBI) isolated from rocket (Eruca sativa) seeds

Isothiocyanates (ITCs), which are organosulfur compounds present in cruciferous vegetables, have anticarcinogenic, antiinflammatory, and antiproliferative activities. These biological activities, and the knowledge that rocket seed (Eruca sativa) extract is used in skin disorders in traditional Middle Eastern medicine, led to the isolation and assessment of 4-methylthiobutylisothiocyanate (MTBI), the major ITC in rocket seeds, for its potential in the prevention of inflammatory skin diseases, such as psoriasis. MTBI was found to depress the growth of activated keratinocytes and to arrest the activated THP-1 monocytes in the G2 stage. Both MTBI and its oxidized derivative sulforaphane (SFN), which was found in the rocket seed at a low concentration, downregulated the expression of the proinflammatory genes, tumor necrosis factor (TNF)-alpha and interleukin (IL)-12/23 p40, as well as that of intercellular adhesion molecule-1, in activated THP-1 cells. These results demonstrate that MTBI may deter the inflammation process, as has been reported for SFN. Furthermore, pretreatment with MTBI hindered the induction of the inflammatory state in the THP-1 cells, as shown by the inhibition of cytokine mRNA expression of IL-1beta, IL-12/23 p40, and TNF-alpha. Overall, our results imply that MTBI may represent a new family of natural compounds possessing significant skin inflammation-preventive activities.

Antioxidant and pro-oxidant capacities of ITCs

Isothiocyanates (ITCs) are breakdown products of glucosinolates contained in cruciciferous vegetables. This heterogeneous family of molecules has the -N=C=S group as its common structural feature and possesses important cytoprotective properties. Their biological interactions are strongly related to modulation of cellular redox status, and a number of studies have documented their indirect antioxidant properties, particularly related to induction of phase-2 enzymes. On the other hand, some direct antioxidant behavior has also been observed for a limited number of ITCs. Paradoxically relevant pro-oxidant properties have also been documented, possibly related to the simultaneous induction of phase-1 enzymes. In this review, we will summarize and discuss the prevailing mechanisms for the antioxidant and pro-oxidant activity of ITCs, both in vivo and in vitro.

Modulation of histone deacetylase activity by dietary isothiocyanates and allyl sulfides: studies with sulforaphane and garlic organosulfur compounds

Histone deacetylase (HDAC) inhibitors reactivate epigenetically-silenced genes in cancer cells, triggering cell cycle arrest and apoptosis. Recent evidence suggests that dietary constituents can act as HDAC inhibitors, such as the isothiocyanates found in cruciferous vegetables and the allyl compounds present in garlic. Broccoli sprouts are a rich source of sulforaphane (SFN), an isothiocyanate that is metabolized via the mercapturic acid pathway and inhibits HDAC activity in human colon, prostate, and breast cancer cells. In mouse preclinical models, SFN inhibited HDAC activity and induced histone hyperacetylation coincident with tumor suppression. Inhibition of HDAC activity also was observed in circulating peripheral blood mononuclear cells obtained from people who consumed a single serving of broccoli sprouts. Garlic organosulfur compounds can be metabolized to allyl mercaptan (AM), a competitive HDAC inhibitor that induced rapid and sustained histone hyperacetylation in human colon cancer cells. Inhibition of HDAC activity by AM was associated with increased histone acetylation and Sp3 transcription factor binding to the promoter region of the P21WAF1 gene, resulting in elevated p21 protein expression and cell cycle arrest. Collectively, the results from these studies, and others reviewed herein, provide new insights into the relationships between reversible histone modifications, diet, and cancer chemoprevention.

Three structurally homologous isothiocyanates exert "Janus" characteristics in human HepG2 cells

In this study, we used the single cell gel electrophoresis (SCGE) assay and the micronucleus (MN) test to investigate the DNA damaging effects and the antigenotoxic potencies of three structurally related ITCs in human HepG2 cells. The results show that all three ITCs possess the characteristic of a "Janus" compound, i.e., they exert both significant genotoxicity and antigenotoxicity, depending on the concentrations used in the test systems applied. Regression line analysis of the results derived by SCGE analysis showed genotoxic potency of the ITCs in the following order: 3-methylthiopropyl ITC (MTPITC) > 4-methylthiobutyl ITC (MTBITC) > 5-methylthiopentyl ITC (MTPeITC); however, this order in genotoxic potency was not confirmed by MN analysis. Additionally, the MN test showed significant mutagenicity of the test substances at higher concentrations when compared with the SCGE assay. Twenty-four hour-treatment of the cells with the ITCs, followed by a 1-hr recovery period, showed significant DNA repair in the SCGE assay at a concentration > or =10 microM MTPITC, > or =3 microM MTBITC, and > or =0.1 microM MTPeITC, respectively. In antigenotoxicity studies, the most effective concentration of MTPITC and MTPeITC toward B(a)P-induced DNA damage was 0.1 muM in both test systems. MTBITC suppressed MN formation in B(a)P-treated cells to the background level at a concentration of 1 muM. The ambivalent character of the ITCs under studymust be further clarified, especially in the possiblecontext of high dose therapeutic applications.

Sesquiterpenes from the sponge Axinyssa isabela

Further research on the constituents of the sponge Axinyssa isabela collected in the Gulf of California has led to the isolation of nine new sesquiterpenes, the eudesmanes axinisothiocyanates M and N (1, 2), the bisabolane axinythiocyanate A (3), and the aristolane derivatives axinysones A-E (4-8) and axinynitrile A (9), together with four known sesquiterpenoids (10-13). The structures of the new metabolites have been established by spectroscopic techniques.The absolute configuration of axinysones A (4) and B (5) has been assigned after esterification with (R)- and (S)-MPA acids. In addition, the unusual nitrile-containing sesquiterpene 9 has been synthesized from (+)-aristolone (14). The cytotoxic activity of the compounds isolated has been tested against three human tumor cell lines.

Acaricidal constituents isolated from Sinapis alba L. seeds and structure-activity relationships

Allyl isothiocyanate (AITC) and phenethyl isothiocyanate (PEITC) were isolated from Sinapis alba L. seeds and their effects against Dermatophagoides farinae and D. pteronyssinus were evaluated using the impregnated fabric disk method. The LD 50 values of their compounds and derivatives were then compared with those of a commercial acaricide, benzyl benzoate. On the basis of the LD 50 values against D. farinae, PEITC (0.21 microg/cm(2)) was the most toxic, followed by benzyl isothiocyanate (0.55 microg/cm(2)), phenyl isothiocyanate (1.09 microg/cm(2)), butyl isothiocyanate (1.24 microg/cm(2)), and AITC (1.36 microg/cm(2)); acetyl isothiocyanate (195.01 microg/cm(2)) was the least toxic. In addition, the acaricidal effects of AITC and PEITC against D. farinae were 7.4- and 47.8-fold greater than those of benzyl benzoate, respectively. Against D. pteronyssinus, PEITC was the most toxic (0.19 microg/cm(2)), followed by benzyl isothiocyanate (0.77 microg/cm(2)), phenyl isothiocyanate (1.37 microg/cm(2)), butyl isothiocyanate (1.50 microg/cm(2)), and AITC (2.88 microg/cm(2)); acetyl isothiocyanate (168.82 microg/cm(2)) was the least toxic. AITC and PEITC were 3.3- and 50.4-fold more active than benzyl benzoate against D. pteronyssinus, respectively. Taken together, these findings indicate that AITC, PEITC, and partial derivatives may be useful as preventive agents against dust mites. In addition, these results indicate that structure-activity is related to the aromatic structure, the number of carbon atoms, and the compounds hydrophobicity.

Isothiocyanate sesquiterpenes from a sponge of the genus axinyssa

The chemical study of a sponge of the genus Axinyssa collected in the Gulf of California has led to the isolation of the new bicyclic sesquiterpenes axinisothiocyanates A-L ( 1- 12) together with the known compounds (1 R,6 S,7 S,10 S)-10-isothiocyanato-4-amorphene ( 13), (4 R*,5 R*,7 S*,10 R*)-4-isocyanoeudesm-11-ene, (-)-epipolasin A, and (+)-aristolone. The structures of the new metabolites have been established by spectroscopic techniques, including the analysis of pyridine-induced 1H NMR chemical shifts. The cytotoxic activity has been tested against three human tumor cell lines.

Papaya seed represents a rich source of biologically active isothiocyanate

In the present study, papaya (Carica papaya) seed and edible pulp were carefully separated and then the contents of benzyl isothiocyanate and the corresponding glucosinolate (benzyl glucosinolate, glucotropaeolin) quantified in each part. The papaya seed with myrosinase inactivation contained >1 mmol of benzyl glucosinolate in 100 g of fresh seed. This content is equivalent to that of Karami daikon (the hottest Japanese white radish) or that of cress. The papaya seed extract also showed a very high activity of myrosinase and, without myrosinase inactivation, produced 460 micromol of benzyl isothiocyanate in 100 g of seed. In contrast, papaya pulp contained an undetectable amount of benzyl glucosinolate and showed no significant myrosinase activity. The n-hexane extract of the papaya seed homogenate was highly effective in inhibiting superoxide generation and apoptosis induction in HL-60 cells, the activities of which are comparable to those of authentic benzyl isothiocyanate.

[Study on apoptosis effect induced by isothiocyanates in broccoli on HepG-2 cells and its mechanism]

OBJECTIVE

To investigate the apoptosis effect of isothiocyanates (ITCS) on human liver cancer cells HepG-2, and its mechanism.

METHOD

HepG-2 cells were treated with different concentrations of ITCS. MTT assay was used to evaluate the influence of ITCS on cell proliferation. Flow cytometry was used to test ROS levels, intracellular mitochondrial transmembrane potential (deltapsim) , and hypodiploid apoptosis peak in HepG-2 cells.

RESULT

ITCS obviously inhibited proliferation of HepG-2 cells. When treated with 15, 30, 60, 120, 240 microg x mL(-1) of ITCS for 24 h, ROS levels were (23.1+/-1. 8)%, (53.3+/-3.3)%, (57.9+/-2.0)%, (79.9+/-3.4)%, (93.4+/-2. 6)% respectively; and deltapsim were (94.8+/-5.5)%, (91.8+/-5.4)%, (66.0+/-5.6)%, (65. 5+/-6.6)% and (44.3+/-2.7)% respectively; when treated with 60, 120, 240 microg x mL(-1) of ITCS for 48 h, cell apoptotic rates were (16.6+/-2.8)%, (21.9+/-4.4) % and (70.2+/-5.3) % respectively.

CONCLUSION

ITCS generates ROS in gastric cancer HepG-2 cells, which causes mitochondrial membrane permeabilization and deltapsim decrease, therefore, leads to apoptosis of HepG-2 cells.

Comparison of growth inhibition profiles and mechanisms of apoptosis induction in human colon cancer cell lines by isothiocyanates and indoles from Brassicaceae

The isothiocyanates sulforaphane and PEITC (beta-phenethyl isothiocyanate) as well as the indoles indole-3-carbinol and its condensation product 3,3'-diindolylmethane are known to inhibit cancer cell proliferation and induce apoptosis. In this study, we compared the cell growth inhibitory potential of the four compounds on the p53 wild type human colon cancer cell line 40-16 (p53(+/+)) and its p53 knockout derivative 379.2 (p53(-/-)) (both derived from HCT116). Using sulforhodamin B staining to assess cell proliferation, we found that the isothiocyanates were strongly cytotoxic, whereas the indoles inhibited cell growth in a cytostatic manner. Half-maximal inhibitory concentrations of all four compounds in both cell lines ranged from 5-15 microM after 24, 48 and 72 h of treatment. Apoptosis induction was analyzed by immunoblotting of poly(ADP-ribose)polymerase (PARP). Treatment with sulforaphane (15 microM), PEITC (10 microM), indole-3-carbinol (10 microM) and 3,3'-diindolylmethane (10 microM) induced PARP cleavage after 24 and 48 h in both 40-16 and the 379.2 cell lines, suggestive of a p53-independent mechanism of apoptosis induction. In cultured 40-16 cells, activation of caspase-9 and -7 detected by Western blotting indicated involvement of the mitochondrial pathway. We detected time- and concentration-dependent changes in protein expression of anti-apoptotic Bcl-x(L) as well as pro-apoptotic Bax and Bak proteins. Of note is that for sulforaphane only, ratios of pro- to anti-apoptotic Bcl-2 family protein levels directly correlated with apoptosis induction measured by PARP cleavage. Taken together, we demonstrated that the glucosinolate breakdown products investigated in this study have distinct profiles of cell growth inhibition, potential to induce p53-independent apoptosis and to modulate Bcl-2 family protein expression in human colon cancer cell lines.

Raphanus sativus and its isothiocyanates inhibit vascular smooth muscle cells proliferation and induce G1 cell cycle arrest

Mu (Raphanus sativus, Korean White Radish) crude extract (Mu-CE) has been studied for its anti-proliferative activity on mouse aortic smooth muscle cells. The abnormal growth of vascular smooth muscle cells (VSMC) is a prominent feature of vascular disease, including atherosclerosis, restenosis after angioplasty. We examined the mechanisms of the action of Mu-CE on VSMC proliferation. The viability of VSMC decreased to 35% at 24 h of treatment with Mu-CE. Treatment of Mu-CE showed potent inhibitory effects on the DNA synthesis of cultured VSMC. In addition, Mu-CE induced apoptosis using cell death ELISA assay. These inhibitory effects were associated with G1 cell cycle arrest. Treatment of Mu-CE, which induced a cell-cycle arrest in G1-phase, induced down-regulation of cyclins and CDKs and up-regulation of the CDK inhibitor p21 expression, whereas up-regulation of p27 by Mu-CE was not observed. Then, total isothiocyanates (ITC) including four different 4-(Methylthio)-3-butenyl isothiocyanate (MTBITC), allyl isothiocayanate (AITC), benzyl isothiocyanate (BITC), and phenethyl isothiocyanate (PEITC) was isolated from n-hexane extracts of Mu. When the VSMC were treated with ITC, the cell viability was significantly decreased. These findings indicate the efficacy of Mu-CE in inhibiting cell proliferation, G1- to S-phase cell-cycle progress on VSMC.

In vitro and in vivo anti-inflammatory activity of a seed preparation containing phenethylisothiocyanate

Winter cress (Barbarea verna) seed preparations rich in phenethylisothiocyanate (PEITC) had strong in vivo and in vitro anti-inflammatory activity, significantly reducing the size of carrageenan-induced rat paw edema. This in vivo effect was comparable with that of the nonsteroidal anti-inflammatory drug aspirin. The seed preparation, in a concentration-dependent manner, reduced the mRNA levels of inflammation-related genes such as the inducible forms of cyclooxygenase and nitric-oxide synthase and the proinflammatory cytokine interleukin in lipopolysaccharide-stimulated mouse macrophage cell line RAW 264.7. Activity of the seed preparation was similar to that of the synthetic PEITC. PEITC was the most active of five different forms of isothiocyanate tested for their effects on in vitro proinflammatory gene expression. In vitro activity of the seed preparation was also compared with that of two known anti-inflammatory drugs. We conclude that Barbarea verna seed preparation may function as a potent anti-inflammatory agent, interfering with the transcription of proinflammatory genes.

BIOFUMIGANT COMPOUNDS RELEASED BY FIELD PENNYCRESS (Thlaspi arvense) SEEDMEAL

Defatted field pennycress (Thlaspi arvense L.) seedmeal was found to completely inhibit seedling germination/emergence when added to a sandy loam soil containing wheat (Triticum aestivum L.) and arugula [Eruca vesicaria (L.) Cav. subsp. sativa (Mill.) Thell.] seeds at levels of 1.0% w/w or higher. Covering the pots with Petri dishes containing the soil-seedmeal mixture decreased germination of both species at the lowest application rate (0.5% w/w), suggesting that the some of the phytotoxins were volatile. CH2Cl2, MeOH, and water extracts of the wetted seedmeal were bioassayed against wheat and sicklepod (Senna obtusifolia (L.) H. S. Irwin & Barneby) radicle elongation. Only the CH2Cl2 extract was strongly inhibitory to both species. Fractionation of the CH2Cl2 extract yielded two major phytotoxins, identified by gas chromatography-mass spectrometry and NMR as 2-propen-1-yl (allyl) isothiocyanate (AITC) and allyl thiocyanate (ATC), which constituted 80.9 and 18.8%, respectively, of the active fraction. When seeds of wheat, arugula and sicklepod were exposed to volatilized AITC and ATC, germination of all three species was completely inhibited by both compounds at concentrations of 5 ppm or less. In field studies, where seedmeal was applied at 0.50, 1.25, and 2.50 kg/m2 and tarped with black plastic mulch, all of the treatments significantly reduced dry weight of bioassay plants compared to the tarped control, with the highest seedmeal rate decreasing dry matter to less than 10% of the control 30 d after seedmeal application. Field pennycress seedmeal appears to offer excellent potential as a biofumigant for high-value horticultural crops for both conventional and organic growers.

Effects of allelochemicals from first (brassicaceae) and second (Myzus persicae and Brevicoryne brassicae) trophic levels on Adalia bipunctata

Three Brassicaceae species, Brassica napus (low glucosinolate content), Brassica nigra (including sinigrin), and Sinapis alba (including sinalbin) were used as host plants for two aphid species: the generalist Myzus persicae and the specialist Brevicoryne brassicae. Each combination of aphid species and prey host plant was used to feed the polyphagous ladybird beetle, Adalia bipunctata. Experiments with Brassicaceae species including different amounts and kinds of glucosinolates (GLS) showed increased ladybird larval mortality at higher GLS concentrations. When reared on plants with higher GLS concentrations, the specialist aphid, B. brassicae, was found to be more toxic than M. persicae. Identification of GLS and related degradation products, mainly isothiocyanates (ITC), was investigated in the first two trophic levels, plant and aphid species, by high-performance liquid chromatography and gas chromatography-mass spectrometry, respectively. While only GLS were detected in M. persicae on each Brassicaceae species, high amounts of ITC were identified in B. brassicae samples (allyl-ITC and benzyl-ITC from B. nigra and S. alba, respectively) from all host plants. Biological effects of allelochemicals from plants on predators through aphid prey are discussed in relation to aphid species to emphasize the role of the crop plant in integrated pest management in terms of biological control efficacy.

Formation and extraction of persistent fumigant residues in soils

Fumigants are commonly thought to be short-lived in soil, but residues have been found in soils years following application. In this study, formation and extraction of persistent soil fumigant residues were investigated. Fumigants 1,3-dichloropropene (1,3-D), chloropicrin (CP), and methyl isothiocyanate (MITC) were spiked into Arlington, Glenelg, and Hagerstown soils and incubated for 30 d under controlled conditions. The incubated soils were evaporated for 20 h prior to extraction with a variety of organic solvents at different temperatures. Extraction with acetonitrile in sealed vials at 80 degrees C for 24 h was the most efficient method to recover persistent soil fumigant residues. At application rates of 1000-1700 mg (kg of soil)(-1), persistent residues of 1,3-D, CP, and MITC in the three soils ranged from 5 to 67 mg kg(-1). The residue content increased with application rate, correlated positively with soil silt content, decreased dramatically as indigenous organic matter (OM) was removed, and changed little with external OM addition. Adsorption to clay surfaces was not important in fumigant retention, while pulverization of soil aggregates significantly decreased persistent fumigant residues. The results suggest that persistent fumigant residues are retained in soil intra-aggregate micropores resulting from binding clay flocs and silt particles by humic substances.

Identification of 6-methylsulfinylhexyl isothiocyanate as an apoptosis-inducing component in wasabi

The ethanol extract from Japanese horseradish wasabi was found to inhibit cell proliferation in human monoblastic leukemia U937 cells by inducing apoptotic cell death. Separation by methods including silica gel chromatography and preparative HPLC gave an active compound, which was identified as 6-methylsulfinylhexyl isothiocyanate (6-HITC). Several lines of evidence indicated that 6-HITC induced apoptosis in U937 cells and human stomach cancer MKN45 cells. Thus, 6-HITC is potentially useful as a natural anti-cancer agent.

The activity of p-methoxybenzylisothiocyanate against Neisseria gonorrhoeae, Haemophilus ducreyi, and other microorganisms

p-Methoxybenzylisothiocyanate was isolated from Lepidium bonariense and found to be responsible for the plants antimicrobial and STD activity. MIC determinations were conducted for p-methoxybenzylisothiocyanate on Haemophilus ducreyi, Neisseria gonorrheae, Candida albicans, Bacillus subtilus, Micrococcus luteus, Staphylococcus aureus, Enterobacter sp., Escherichia coli, Klebsiella pneumoniae, and Psuedomanas aeruginosa. An in vitro cellular toxicity assay showed that at 100 microM (17,9 microg/mL) p-methoxybenzylisothiocyanate is not toxic to living cells.

Benzyl isothiocyanate is the chief or sole anthelmintic in papaya seed extracts

Papaya (Carica papaya) seeds were extracted in an aqueous buffer or in organic solvents, fractionated by chromatography on silica and aliquots tested for anthelmintic activity by viability assays using Caenorhabditis elegans. For all preparations and fractions tested, anthelmintic activity and benzyl isothiocyanate content correlated positively. Aqueous extracts prepared from heat-treated seeds had no anthelmintic activity or benzyl isothiocyanate content although both appeared when these extracts were incubated with a myrosinase-containing fraction prepared from papaya seeds. A 10 h incubation of crude seed extracts at room temperature led to a decrease in anthelmintic activity and fractionated samples showed a lower benzyl isothiocyanate content relative to non-incubated controls. Benzyl thiocyanate, benzyl cyanide, and benzonitrile were not detected in any preparations and cyanogenic glucosides. which were present, could not account for the anthelmintic activity detected. Thus, our results are best explained if benzyl isothiocyanate is the predominant or sole anthelmintic agent in papaya seed extracts regardless of how seeds are extracted.

Study of the role of antimicrobial glucosinolate-derived isothiocyanates in resistance of Arabidopsis to microbial pathogens

Crude aqueous extracts from Arabidopsis leaves were subjected to chromatographic separations, after which the different fractions were monitored for antimicrobial activity using the fungus Neurospora crassa as a test organism. Two major fractions were obtained that appeared to have the same abundance in leaves from untreated plants versus leaves from plants challenge inoculated with the fungus Alternaria brassicicola. One of both major antimicrobial fractions was purified to homogeneity and identified by 1H nuclear magnetic resonance, gas chromatography/electron impact mass spectrometry, and gas chromatography/chemical ionization mass spectrometry as 4-methylsulphinylbutyl isothiocyanate (ITC). This compound has previously been described as a product of myrosinase-mediated breakdown of glucoraphanin, the predominant glucosinolate in Arabidopsis leaves. 4-Methylsulphinylbutyl ITC was found to be inhibitory to a wide range of fungi and bacteria, producing 50% growth inhibition in vitro at concentrations of 28 microM for the most sensitive organism tested (Pseudomonas syringae). A previously identified glucosinolate biosynthesis mutant, gsm1-1, was found to be largely deficient in either of the two major antimicrobial compounds, including 4-methylsulphinylbutyl ITC. The resistance of gsm1-1 was compared with that of wild-type plants after challenge with the fungi A. brassicicola, Plectosphaerella cucumerina, Botrytis cinerea, Fusarium oxysporum, or Peronospora parasitica, or the bacteria Erwinia carotovora or P. syringae. Of the tested pathogens, only F. oxysporum was found to be significantly more aggressive on gsm1-1 than on wild-type plants. Taken together, our data suggest that glucosinolate-derived antimicrobial ITCs can play a role in the protection of Arabidopsis against particular pathogens.

Study of the role of antimicrobial glucosinolate-derived isothiocyanates in resistance of Arabidopsis to microbial pathogens

Crude aqueous extracts from Arabidopsis leaves were subjected to chromatographic separations, after which the different fractions were monitored for antimicrobial activity using the fungus Neurospora crassa as a test organism. Two major fractions were obtained that appeared to have the same abundance in leaves from untreated plants versus leaves from plants challenge inoculated with the fungus Alternaria brassicicola. One of both major antimicrobial fractions was purified to homogeneity and identified by 1H nuclear magnetic resonance, gas chromatography/electron impact mass spectrometry, and gas chromatography/chemical ionization mass spectrometry as 4-methylsulphinylbutyl isothiocyanate (ITC). This compound has previously been described as a product of myrosinase-mediated breakdown of glucoraphanin, the predominant glucosinolate in Arabidopsis leaves. 4-Methylsulphinylbutyl ITC was found to be inhibitory to a wide range of fungi and bacteria, producing 50% growth inhibition in vitro at concentrations of 28 microM for the most sensitive organism tested (Pseudomonas syringae). A previously identified glucosinolate biosynthesis mutant, gsm1-1, was found to be largely deficient in either of the two major antimicrobial compounds, including 4-methylsulphinylbutyl ITC. The resistance of gsm1-1 was compared with that of wild-type plants after challenge with the fungi A. brassicicola, Plectosphaerella cucumerina, Botrytis cinerea, Fusarium oxysporum, or Peronospora parasitica, or the bacteria Erwinia carotovora or P. syringae. Of the tested pathogens, only F. oxysporum was found to be significantly more aggressive on gsm1-1 than on wild-type plants. Taken together, our data suggest that glucosinolate-derived antimicrobial ITCs can play a role in the protection of Arabidopsis against particular pathogens.

Antiplatelet and anticancer isothiocyanates in Japanese domestic horseradish, Wasabi

6-Methylsulfinylhexyl isothiocyanate (MS-ITC) was isolated from wasabi (Wasabia japonica, Japanese domestic horseradish) as a potential inhibitor of human platelet aggregation in vitro through our extensive screening of vegetables and fruits. In the course of an another screening for the induction of glutathione S-transferase (GST) activity in RL34 cells, MS-ITC was inadvertently isolated from wasabi as a potential inducer of GST. MS-ITC administered to rats or mice also showed both activities in vivo. As a result from elucidation of the platelet aggregation inhibition and the GST induction mechanisms of MS-ITC, the isothiocyanate moiety of MS-ITC plays an important role for antiplatelet and anticancer activities because of its high reactivity with sulfhydryl (RSH) groups in biomolecules (GSH, cysteine residue in a certain protein, etc.).

Supercritical fluid chromatography as a method of analysis for the determination of 4-hydroxybenzylglucosinolate degradation products

In the present study analytical and preparative supercritical fluid chromatography (SFC) were used for investigation of myrosinase catalysed degradation of 4-hydroxybenzylglucosinolate (sinalbin). Sinalbin occurs as a major glucosinolate in seeds of Sinapis alba L., in various mustards and other food products. The degradation products were identified and quantified by analysis based on a developed SFC method using a bare silica column. Determinations comprised transformation products of sinalbin, produced both during degradation of isolated sinalbin, and during autolysis of meal from S. alba seeds. The conditions in the developed SFC method were used as basis for the preparative SFC procedure applied for isolation of the components prior to their identification by nuclear magnetic resonance (NMR) spectroscopy. Myrosinase catalysed sinalbin hydrolysis resulted in the reactive 4-hydroxybenzyl isothiocyanate as an initial product at pH values from 3.5 to 7.5 whereas 4-hydroxybenzyl cyanide was one of the major products at low pH values. 4-Hydroxybenzyl isothiocyanate was found to disappear from the aqueous reaction mixtures in a few hours, as it reacted easily with available nucleophilic reagents. 4-Hydroxybenzyl alcohol was found as the product from reaction with water, and with ascorbic acid, 4-hydroxybenzylascorbigen was produced.

Antiplatelet and anticancer isothiocyanates in Japanese domestic horseradish, wasabi

6-Methylsulfinylhexyl isothiocyanate (MS-ITC) was isolated from wasabi (Wasabia japonica, Japanese domestic horseradish) as a potential inhibitor of human platelet aggregation in vitro through our extensive screening of vegetables and fruits. In the course of another screening for the induction of glutathione S-transferase (GST) activity in RL34 cells. MS-ITC was inadvertently isolated from wasabi as a potential inducer of GST. MS-ITC administered to rats or mice also showed both activities in vivo. As a result from elucidation of the platelet aggregation inhibition and the GST induction mechanisms of MS-ITC, the isothiocyanate moiety of MS-ITC plays an important role for antiplatelet and anticancer activities because of its highly reactivity with sulfhydryl (-SH) groups in biomolecules (GSH, cysteine residue in a certain protein, etc.).

6-Methylsulfinylhexyl isothiocyanate and its homologues as food-originated compounds with antibacterial activity against Escherichia coli and Staphylococcus aureus

Cruciferae plants, banana and coriander each showed antibacterial activity. The highest activity among the food-stuffs tested was found in the stems of wasabi. An ethereal extract from wasabi stems had potent antibacterial activity and we isolated the active compound from the extract. Instrumental analysis identified the compound as 6-methylsulfinylhexyl isothiocyanate. Some homologues of 6-methylsulfinylhexyl isothiocyanate were also active against Escherichia coli and Staphylococcus aureus.

Dietary levels of plant phenols and other non-nutritive components: could they prevent cancer?

Several non-nutritive components in fruits, vegetables, herbs and spices have been found to inhibit tumour formation in experimental animals exposed to carcinogens. The active non-nutritive components vary with respect to their chemical structures, and may be classed as phenols, terpenes, indoles, isothiocyanates, allyl sulphides or others. They also seem to work by different mechanisms, being inducers or inhibitors of various enzymes, antioxidants, scavengers of reactive metabolites, or inducers of apoptosis. The dietary levels are generally in the order of 1-100 mg/day for most classes of compounds in the Danish population, and similar levels are expected in most northern European countries. These levels are very low compared with the levels used in most animal experiments, where non-nutritive factors have individually been shown to have inhibitory actions on tumorigenesis. Human long-term intervention trials with antioxidants have generally been discouraging. In human short-term intervention studies, where increased dietary levels of specific vegetables or fruits are studied, doses are also comparatively low. Effects on important enzymes have been reported in several such studies, indicating that low levels of non-nutritive factors could influence carcinogenesis by specific mechanisms. Meta-analyses of cohort studies on specific food items rich in specific non-nutritive components, indicate that carotenoid- or glucosinolate-rich foods protect against some cancers, while flavonoid rich food items do not uniformly show protective effects.

Broccoli sprouts: an exceptionally rich source of inducers of enzymes that protect against chemical carcinogens

Induction of phase 2 detoxication enzymes [e.g., glutathione transferases, epoxide hydrolase, NAD(P)H: quinone reductase, and glucuronosyltransferases] is a powerful strategy for achieving protection against carcinogenesis, mutagenesis, and other forms of toxicity of electrophiles and reactive forms of oxygen. Since consumption of large quantities of fruit and vegetables is associated with a striking reduction in the risk of developing a variety of malignancies, it is of interest that a number of edible plants contain substantial quantities of compounds that regulate mammalian enzymes of xenobiotic metabolism. Thus, edible plants belonging to the family Cruciferae and genus Brassica (e.g., broccoli and cauliflower) contain substantial quantities of isothiocyanates (mostly in the form of their glucosinolate precursors) some of which (e.g., sulforaphane or 4-methylsulfinylbutyl isothiocyanate) are very potent inducers of phase 2 enzymes. Unexpectedly, 3-day-old sprouts of cultivars of certain crucifers including broccoli and cauliflower contain 10-100 times higher levels of glucoraphanin (the glucosinolate of sulforaphane) than do the corresponding mature plants. Glucosinolates and isothiocyanates can be efficiently extracted from plants, without hydrolysis of glucosinolates by myrosinase, by homogenization in a mixture of equal volumes of dimethyl sulfoxide, dimethylformamide, and acetonitrile at -50 degrees C. Extracts of 3-day-old broccoli sprouts (containing either glucoraphanin or sulforaphane as the principal enzyme inducer) were highly effective in reducing the incidence, multiplicity, and rate of development of mammary tumors in dimethylbenz(a)anthracene-treated rats. Notably, sprouts of many broccoli cultivars contain negligible quantities of indole glucosinolates, which predominate in the mature vegetable and may give rise to degradation products (e.g., indole-3-carbinol) that can enhance tumorigenesis. Hence, small quantities of crucifer sprouts may protect against the risk of cancer as effectively as much larger quantities of mature vegetables of the same variety.

Myrosinase-generated isothiocyanate from glucosinolates: isolation, characterization and in vitro antiproliferative studies

Epidemiological and pharmacological studies have shown that colorectal cancer development could be reduced by consuming vegetables that contain glucosinolates. In view of this the effect of some glucosinolates and their isothiocyanate (ITC)-derived products on in vitro cell growth was studied. We report the isolation and characterization of ITCs derived from glucosinolates by using HPLC, GC-MS, and NMR techniques. The in vitro activity of ITCs on human erythroleukemic K562 cells has been investigated by using two alternative approaches: the in situ and pre-mix methods. No differences in antiproliferative activity were found comparing the effect of ITCs produced either of these methods. In the experimental conditions used, the production of ITCs from glucosinolates is almost quantitative as confirmed by HPLC or GC-MS analysis. The ITCs' inhibitory activity on K562 cells growth is particularly evident in the cases of ITCs derived from sinigrin, progoitrin, epi-progoitrin, glucotropaeolin and glucocheirolin. Finally, the antiproliferative activity of the ITCs obtained from glucoraphenin, taken as an example, was determined on other tumor cell lines with a different origin and hystotype. Considering the antiproliferative activity found for ITCs these compounds could be considered potentially responsible for the reduction of colorectal cancer associated with diets rich in cruciferous vegetables. Further studies will be aimed at the possible application of glucosinolate-derived products as chemopreventive cancer agents.