The effect of 6-methylthiohexyl isothiocyanate isolated from Wasabia japonica (wasabi) on 4-(methylnitrosamino)-1-(3-pyridyl)-1-buatnone-induced lung tumorigenesis in mice

Chemical composition of extracts from leaves, stems and roots of wasabi (Eutrema japonicum) and their anti-cancer, anti-inflammatory and anti-microbial activities

The purpose of our study was to evaluate the composition of the extracts obtained from the roots and leaves of Eutrema japonicum cultivated in Poland. For this purpose, LC-DAD-IT-MS and LC-Q-TOF-MS analyses were used. The results revealed the presence of forty-two constituents comprising glycosinolates, phenylpropanoid glycosides, flavone glycosides, hydroxycinnamic acids, and other compounds. Then, the resultant extracts were subjected to an assessment of the potential cytotoxic effect on human colon adenocarcinoma cells, the effect on the growth of probiotic and intestinal pathogenic strains, as well as their anti-inflammatory activity. It was demonstrated that 60% ethanol extract from the biennial roots (WR2) had the strongest anti-inflammatory, antibacterial, and cytotoxic activities compared to the other samples. Our results suggest that extracts from E. japonicum may be considered as a promising compound for the production of health-promoting supplements.

Developing multifunctional crops by engineering Brassicaceae glucosinolate pathways

Glucosinolates (GSLs), found mainly in species of the Brassicaceae family, are one of the most well-studied classes of secondary metabolites. Produced by the action of myrosinase on GSLs, GSL-derived hydrolysis products (GHPs) primarily defend against biotic stress in planta. They also significantly affect the quality of crop products, with a subset of GHPs contributing unique food flavors and multiple therapeutic benefits or causing disagreeable food odors and health risks. Here, we explore the potential of these bioactive functions, which could be exploited for future sustainable agriculture. We first summarize our accumulated understanding of GSL diversity and distribution across representative Brassicaceae species. We then systematically discuss and evaluate the potential of exploited and unutilized genes involved in GSL biosynthesis, transport, and hydrolysis as candidate GSL engineering targets. Benefiting from available information on GSL and GHP functions, we explore options for multifunctional Brassicaceae crop ideotypes to meet future demand for food diversification and sustainable crop production. An integrated roadmap is subsequently proposed to guide ideotype development, in which maximization of beneficial effects and minimization of detrimental effects of GHPs could be combined and associated with various end uses. Based on several use-case examples, we discuss advantages and limitations of available biotechnological approaches that may contribute to effective deployment and could provide novel insights for optimization of future GSL engineering.

Anti-tumor effect of Wasabi component, 6-(methylsulfinyl) hexyl isothiocyanate, against endometrial carcinoma cells

PURPOSE

Wasabi is a traditional plant seasoning with an anti-septic function. Recent studies revealed several functions of Wasabi, such as anti-inflammation; however, the anti-tumor effect against endometrial carcinoma (EMC) cells has not been examined. In the present study, we investigated the anti-tumor effect of 6-(methylsulfinyl) hexyl isothiocyanate (6-MITC), a major chemical compound of Wasabi, against various EMC cell lines in vitro and in vivo.

METHODS

The effect of 6-MITC on cell viability was measured by the WST-1 assay in EMC and HUVEC cells. The impact of 6-MITC oral administration in nude mice was measured to assess the growth of the EMC xenograft and natural killer (NK) cell activity in the spleen.

RESULTS

The addition of 6-MITC suppressed the proliferation of EMC cells (Ishikawa, HEC265, HEC108, KLE, and HEC1B) dose-dependently, but not HUVEC cells. 6-MITC (5 µM) enhanced the cisplatin sensitivity of EMC cells. 6-MITC induced apoptosis in a dose-dependent fashion in EMC cells other than HEC1B cells and was associated with increased expression of cleaved-caspase3 and decreased expression of BCL2. Oral administration of 6-MITC (2 and 4 µmol/kg) to Ishikawa and HEC1B xenografting mice resulted in a reduced tumor volume compared with the control (P < 0.05, 4 µmol/kg). Immunohistochemical staining of resected tumors revealed increased expression of Ki-67 and reduced cleaved-caspase3. Furthermore, 6-MITC treatment enhanced NK cell activity, especially when administered before tumor xenografting.

CONCLUSION

These results indicate that 6-MITC has a marked anti-tumor effect against EMC cells and a novel effect to enhance NK cell activity. These effects suggest the therapeutic potential of 6-MITC.

Administration of Wasabia koreana Ameliorates Irritable Bowel Syndrome-Like Symptoms in a Zymosan-Induced Mouse Model

Irritable bowel syndrome (IBS) is a functional gastrointestinal disease with complex pathophysiology involving the brain-gut axis. To assess the effects of Wasabia koreana (WK) on IBS, we employed a mouse model of colonic zymosan injection presenting with diarrhea-predominant IBS-like symptoms. Oral WK administration significantly diminished stool score, suppressed colon length and weight change, and minimized body weight loss without affecting food intake. In WK-treated mice, the submucosal thickening and epithelial lining of the colon were inhibited and were similar to those of naïve mice. Infiltration of mast cells into the colon and serum tumor necrosis factor-α levels were markedly suppressed. These effects were comparable to those of sulfasalazine, an anti-inflammatory drug. Furthermore, the number of visceral pain-related behaviors was significantly decreased, and locomotion activities measured in the elevated plus maze and open field tests were significantly increased by WK in a dose-dependent manner compared with amitriptyline, an antidepressant. These changes were accompanied by reduced FosB2 expression in the brain. Taken together, these data suggest that WK may have potential as a medicinal food for IBS by acting on inflammatory diarrhea and neural activity.

Improvement Effects of Wasabi (Wasabia japonica) Leaves and Allyl Isothiocyanate on Stomach Lesions of Mongolian Gerbils Infected with Helicobacter pylori

The relationship between Helicobacter pylori infection and gastric cancer associated with stomach lesions has been reported. Improvement of the adverse effects induced by H. pylori is required for human health. It has been reported that wasabi ( Wasabia japonica Matsum) leaves have various effects on bacteria and mammals. In this study, the effect was examined of wasabi leaf extract and allyl isothiocyanate (AIT), which is a main functional component of wasabi, on stomach lesions in Mongolian gerbils infected with H. pylori. After the gerbils infected with H. pylori were orally administrated with wasabi leaf extract and AIT for two weeks, colony forming units (CFU) of H. pylori, the degree of gastric mucosal erosion, and petechial hemorrhage in the stomachs of the gerbils were evaluated. Wasabi leaf extract and AIT exhibited a decreasing tendency of CFU in the stomachs. The degree of gastric mucosal erosion and petechial hemorrhage were significantly decreased by the intake of wasabi leaf extract and AIT. Wasabi leaf extract and AIT did not affect body weight, dietary intake, water intake, and the pH of the stomach. From these results, wasabi leaves and AIT may provide a natural remedy for stomach lesions induced by H. pylori.

The induction of apoptosis and autophagy by Wasabia japonica extract in colon cancer

PURPOSE

Wasabia japonica (wasabi) has been shown to exhibit properties of detoxification, anti-inflammation and the induction of apoptosis in cancer cells. This study aimed to investigate the molecular mechanism of the cytotoxicity of wasabi extract (WE) in colon cancer cells to evaluate the potential of wasabi as a functional food for chemoprevention.

METHODS

Colo 205 cells were treated with different doses of WE, and the cytotoxicity was analyzed by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl tetrazolium bromide. Apoptosis and autophagy were detected by 4',6-diamidino-2-phenylindole, 5,5',6,6'-tetrachloro-1,1',3,3'-tetraethyl-imidacarbo-yanine iodide and staining for acidic vascular organelles (AVOs), along with Western blotting.

RESULTS

The results demonstrated that WE induced the extrinsic pathway and mitochondrial death machinery through the activation of TNF-α, Fas-L, caspases, truncated Bid and cytochrome C. WE also induced autophagy by decreasing the phosphorylation of Akt and mTOR and promoting the expression of microtubule-associated protein 1 light chain 3-II and AVO formation. An in vivo xenograft model verified that tumor growth was delayed by WE treatment.

CONCLUSION

Our studies revealed that WE exhibits anti-colon cancer properties through the induction of apoptosis and autophagy. These results provide support for the application of WE as a chemopreventive functional food and as a prospective treatment of colon cancer.

Modulation of Nrf2/Keap1 system by Wasabi 6-methylthiohexyl isothiocyanate in ARE-mediated NQO1 expression

SCOPE

6-Methylthiohexyl isothiocyanate (6-MTITC), one of the major bioactive ingredients in Japanese Wasabi, has revealed cytoprotective and cancer chemopreventive effects. This study aims to clarify the molecular mechanisms how 6-MTITC modulates nuclear factor E2-related factor 2 (Nrf2)/Kelchlike ECH-associating protein 1 (Keap1) system in antioxidant-responsive element (ARE)-mediated nicotinamide adenine dinucleotide phosphate (NADP): quinone oxidoreductase 1 (NQO1) expression.

METHODS AND RESULTS

HepG2 cells were treated with 6-MTITC with varying time and dose. NQO1, Nrf2, and Keap1 proteins were detected by Western blotting. ARE transactivation was detected by electrophilic mobility shift assay and reporter gene assay. Nuclear localization of Nrf2 was determined by immunocytochemistry assay. Ubiquitination of Nrf2 and Keap1 was detected using immunoprecipitation after treatment with MG132. Small interfering RNA was used to knockdown Nrf2 or Keap1. The results revealed that 6-MTITC modulated Nrf2/ARE pathway by stimulating Keap1 modification, and inhibiting Nrf2 ubiquitination and protein turnover. These actions finally increased nuclear Nrf2 accumulation and ARE-binding activity. Moreover, silencing Nrf2 markedly reduced ARE-driven activity induced by 6-MTITC.

CONCLUSION

6-MTITC modulated ARE-driven NQO1 expression by stabilizing Nrf2 with enhanced Keap1 modification and decreased Nrf2 degradation.

Isothiocyanates from Wasabia japonica activate transient receptor potential ankyrin 1 channel

6-(Methylsulfinyl)hexyl isothiocyanate (6-MSITC) and 6-(methylthio)hexyl isothiocyanate (6-MTITC) have low pungency and are responsible for the fresh flavor of wasabi (Wasabia japonica [Miq] Matsumura). In this study, we found that these two isothiocyanates activate transient receptor potential ankyrin 1 (TRPA1), and 6-MSITC activates transient receptor potential vanilloid 1 (TRPV1), but not other transient receptor potential channels expressed in sensory neurons. Both 6-MSITC and 6-MTITCinduced intracellular Ca(2+) increases in human embryonic kidney-derived 293 cells expressing mouse TRPA1 (mTRPA1) as measured by Ca(2+) imaging. In whole-cell patch-clamp recordings, 6-MSITC and 6-MTITC dose-dependently activated both mTRPA1 (EC(50) = 147±26 µM for 6-MSITC and 30±3 µM for 6-MTITC) and human TRPA1 (hTRPA1; EC(50) = 39±4 µM for 6-MSITC and 34±3 µM for 6-MTITC). In addition, TRPA1 N-terminal cysteines, which are reported to be important for channel activation by electrophilic ligands, were involved in 6-MSITC- and 6-MTITC-evoked TRPA1 activation. These isothiocyanates also activated endogenous TRPA1 expressed in mouse dorsal root ganglion neurons and intraplantar injection of 10-30 mM 6-MSITC-evoked pain-related behaviors in mice. These results indicate the following: 1) 6-MSITC and 6-MTITC activate both mTRPA1 and hTRPA1; 2) 6-MSITC activates mTRPV1; and 3) the pharmacological functions of these isothiocyanates could be derived from TRPA1 activation.

Signaling actions of electrophiles: anti-inflammatory therapeutic candidates

Over the past several years, research on biologically relevant electrophiles has been replete with new insights, expanding our understanding of the roles electrophiles play in vivo. Importantly, many electrophiles can form reversible covalent adducts with both proteins and small-molecule thiols in cells. This post-translational protein modification has important ramifications, including changes in protein enzymatic activity, the transduction of signals within and between cells, and alterations in gene expression. Electrophiles modulate a variety of cellular signaling processes that are involved in several major diseases with inflammatory components. The electrophilic fatty-acid derivatives discussed in this work are naturally occurring products of redox reactions and enzymatic activity. Furthermore, several of these electrophilic species and their derivatives represent potential therapeutic candidates.

Chemoprevention of 1,2-dimethylhydrazine-induced colonic preneoplastic lesions in Fischer rats by 6-methylsulfinylhexyl isothiocyanate, a wasabi derivative

The preventive effects of dietary exposure to a wasabi derivative 6-methylsulfinylhexyl isothiocyanate (6-MSITC) during the initiation and post-initiation phases on the development of 1,2-dimethylhydrazine (DMH)-induced colonic aberrant crypt foci (ACF), and β-catenin-accumulated crypts (BCAC) were investigated in male F344 rats. To induce ACF and BCAC, rats were given four weekly subcutaneous injections of DMH (40 mg/kg body weight). The rats also received diets containing 200 or 400 ppm 6-MSITC during the initiation or post-initiation phases. The experiment was terminated 12 weeks after the start. DMH exposure produced a substantial number of ACF (323.8±69.7/colon) and BCAC (3.80±1.05/cm(2)) at the end of the study. Dietary administration of 6-MSITC at a dose of 400 ppm during the initiation phase caused a significant reduction in the total number of ACF (52% reduction, P<0.0001), larger ACF (4 or more crypt ACF) (58% reduction, P<0.001) and BCAC (76% reduction, P<0.00001). The dietary exposure to 6-MSITC significantly reduced the size (crypt multiplicity) of BCAC during both initiation and post-initiation treatment when compared to group 1 treated with DMH alone. Immunohistochemically, 6-MSITC administration lowered the proliferating cell nuclear antigen labeling index in ACF and BCAC. In addition, protein levels of hepatic cytochrome P-450 isozymes at 24 h after 6-MSITC exposure were significantly suppressed (P<0.01). The results indicated that 6-MSITC exerted chemopreventive effects in the present short-term colon carcinogenesis bioassay, through alterations in cell proliferation activity and drug metabolizing enzyme levels.

Anti-oxidant and Anti-hypercholesterolemic Activities of Wasabia japonica

The effects of Wasabia japonica (WJ) were investigated in vitro and in vivo for their anti-oxidant and anti-hypercholesterolemic activities. It was found that the aqueous extracts of WJ leaves (WJL) had strong scavenging activities towards 1,1-Diphenyl-2-picryhydrazyl (DPPH) and nitric oxide (NO) free radicals in cell free systems. WJL also inhibited NO production and the expressions of inducible NO synthase (iNOS) mRNA and enzyme protein, determined by Griess reactions, RT-PCR or Western blotting respectively in Lipopolysaccharide (LPS)-stimulated RAW 264.7 macrophages cells. The anti-hypercholesterolemic effects of WJ diet were investigated in hypercholesterolemia rats. Sprague-Dawley rats were divided into four groups and were fed with either normal diet (Group 1), or diet containing 1%(w/w) cholesterol (Groups 2, 3 and 4). After 4 weeks, Group 2 was changed to normal diet, Groups 3 and 4 were changed to the diet containing 5% WJ leaf and or 5% WJ root, respectively. 3 weeks after WJ diets, Serum HDL-cholesterol levels were significantly increased in WJ diet groups compared with the normal diet hypercholesterolemia rats. In contrast, the serum LDL-cholesterol levels and liver xanthine oxidase (XO) activity in WJ diet groups were significantly decreased. The results indicate that the WJ extracts have significant anti-oxidant activities, and the WJ diet exhibited anti-hypercholesterolemic action in high cholesterol diet rats, which was companied with modulations of cholesterol metabolism and decrease in liver XO activity.

Antioxidant phenylpropanoid glycosides from the leaves of Wasabia japonica

From the MeOH extract of the leaves of W. japonica, seven phenylpropanoid gentiobiosides (1-7) were isolated along with eight known phenylpropanoids (8-15). Structures of 1-7 were determined based on spectroscopic data and chemical evidence. The activity of compounds 1-15 to scavenge superoxide anion radicals was investigated using an electron spin resonance (ESR) method.

Inhibition of lipopolysaccharide-induced cyclooxygenase-2 transcription by 6-(methylsulfinyl) hexyl isothiocyanate, a chemopreventive compound from Wasabia japonica (Miq.) Matsumura, in mouse macrophages

6-(Methylsulfinyl)hexyl isothiocyanate (6-MITC) is a chemopreventive compound occurring in Wasabi (Wasabia japonica (Miq.) Matsumura), which is a very popular pungent spice in Japan. We investigated the effects of 6-MITC on the expression of cyclooxygenase-2 (COX-2) in lipopolysaccharide (LPS)-activated murine macrophage RAW264 cells. Treatment with 6-MITC suppressed LPS-mediated induction of COX-2 protein in a dose-dependent manner. Transfections with various COX-2 promoter reporter constructs revealed that the inhibitory effects of 6-MITC on COX-2 gene expression were directed by the core promoter elements including nuclear factor kappaB (NF-kappaB), CCAAT/enhancer-binding protein (C/EBP) and cyclic AMP-response element (CRE) sites. Western blotting analysis showed that 6-MITC inhibited LPS-induced activation of MAPK (ERK, p38 kinase and JNK) and transcriptional factors (CREB, c-Jun and C/EBPdelta) binding the core elements of COX-2 promoter, substantiating the involvement of these signal transduction pathways in the regulation of COX-2 expression by 6-MITC. Moreover, Western blotting experiments with MAPK-specific inhibitors (U0126 for MEK1/2, SB203580 for p38 kinase and SP600125 for JNK) demonstrated that 6-MITC suppressed LPS-induced COX-2 expression by blocking the activation of JNK-mediated AP-1 and ERK/p38 kinase-mediated CREB or C/EBPdelta. Finally, the structure-activity study revealed that the inhibitory potency of methylsulfinyl isothiocyanates (MITCs) depended on the methyl chain length. These findings demonstrate for the first time that 6-MITC is an effective agent to attenuate COX-2 production, and enhance our understanding of the anti-inflammation properties of 6-MITC.

Colon cancer proliferating desulfosinigrin in wasabi (Wasabia japonica)

A reduced incidence of different types of cancer has been linked to consumption of Brassica vegetables, and there is evidence that glucosinolates (GSLs) and their hydrolysis products play a role in reducing cancer risk. Wasabi (Wasabia japonica) and horseradish (Armoracia rusticana), both Brassica vegetables, are widely used condiments both in Japanese cuisine and in the United States. Desulfosinigrin (DSS) (1) was isolated from a commercially available wasabi powder and from fresh wasabi roots. Sinigrin (2) was isolated from horseradish roots. DSS and sinigrin were evaluated for their inhibitory effects on cyclooxygenase-1 (COX-1) and cyclooxygenase-2 (COX-2) enzymes, on lipid peroxidation, and on the proliferation of human colon (HCT-116), breast (MCF-7), lung (NCIH460), and central nervous system (CNS, SF-268) cancer cell lines. DSS did not inhibit COX enzymes or lipid peroxidation at 250 microg/ml. Sinigrin inhibited lipid peroxidation by 71% at 250 microg/ml. However, DSS promoted the growth of HCT-116 (colon) and NCI H460 (lung) human cancer cells as determined by the MTT assay in a concentration-dependent manner. At 3.72 microg/ml, a 27% increase in the number of viable human HCT-116 colon cancer cells was observed; the corresponding increases at 7.50 and 15 microg/ml were 42 and 69%, respectively. At 60 microg/ml, DSS doubled the number of HCT-16 colon cancer cells. For NCI H460 human lung cancer cells, DSS at 60 microg/ml increased the cell number by 20%. Sinigrin showed no proliferating effect on the tumor cells tested. This is the first report of the tumor cell-proliferating activity by a desulfoglucosinolate, the biosynthetic precursor of GSLs found in Brassica spp.

Selective sensitivity to wasabi-derived 6-(methylsulfinyl)hexyl isothiocyanate of human breast cancer and melanoma cell lines studied in vitro

Recently, attention has focused on the anticancer properties of an aromatic component 6-(methylsulfinyl)hexyl isothiocyanate (6-MITC) in a typical Japanese spice, wasabi. In this paper, anticancer activity of 6-MITC in vitro was studied by using a human cancer cell (HCC) panel. 6-MITC directly affected the cells in the HCC panel and inhibited their growth in culture. The mean concentration required to inhibit 50% of control cell growth was 3.9 microM, which is a sufficiently low dosage for practical use. The suppression influenced not only the cell growth, but also the survival of these cells. The mean concentration to suppress cells to a 50% survival was 43.7 microM. The reduction activity of 6-MITC was differential, and it suppressed specific cells. These severely suppressed cell lines included breast cancer and melanoma cell lines. For example, one melanoma line was seriously damaged at a concentration of 0.3 microM of 6-MITC. Compared with other MITCs (2-MITC, 4-MITC and 8-MITC), 6-MITC showed the most effective suppression and with the most specific manner of the cells mentioned above. A "COMPARE" analysis using a computerized algorithm, which was based on the HCC database, suggested that the suppression mechanism of 6-MITC is unique and may be different from that of other known chemicals. The actual mechanism may not a simple one but may involve multiple pathways. On account of its sufficiently small size, 6-MITC is a new possible candidate for controlling cancer cells.

Inhibitory effects of 7-hydroxy-3-methoxy-cadalene on 4-(methylinitrosamino)-1-(3-pyridyl)-1-butanone (NNK)-induced lung tumorigenesis in A/J mice

The present study was undertaken to estimate the effect of 7-hydroxy-3-methoxycadalene (cadalene) extracted from Zelkova serrata on 4-(methylinitrosamino)-1-(3-pyridyl)-1-butanone (NNK)-induced lung tumorigenesis in A/J mice. Twenty mice received orally NNK at a dose of 65 microg/ml water for 7 weeks following by free feeding of a commercial diet not containing cadalene for 2 weeks. Control group was maintained without NNK and cadalene administration and/or treatment groups with NNK and cadalene (6.25, 25, 100 mg/kg feed) feeding for 25 weeks. Lung tumors were induced by NNK at incidence ranging from 10 to 45%. Cadalene treatment (100 mg/kg feed) group significantly reduced the incidence of adenomas from 45 to 10% (P < 0.05), and other cadalene treatment group decreased cancer incidences in a concentration dependent manner. The results of our study strongly indicate that cadalene is capable of inhibiting development of NNK-induced lung tumorigenesis in A/J mice.

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.