Ascorbigen and other indole-derived compounds from Brassica vegetables and their analogs as anticarcinogenic and immunomodulating agents

Unlocking Diversity: From Simple to Cutting-Edge Synthetic Methodologies of Bis(indolyl)methanes

From a synthetic perspective, bis(indolyl)methanes have undergone extensive investigation over the past two to three decades owing to their remarkable pharmacological activities, encompassing anticancer, antimicrobial, antioxidant, and antiinflammatory properties. These highly desirable attributes have spurred significant interest within the scientific community, leading to the development of various synthetic strategies that are not only more efficient but also ecofriendly. This synthesis-based literature review delves into the advancements made in the past 5 years, focusing on the synthesis of symmetrical as well as unsymmetrical bis(indolyl)methanes. The review encompasses a wide array of methods, ranging from well-established techniques to more unconventional and innovative approaches. Furthermore, it highlights the exploration of various substrates, encompassing readily available chemicals such as indole, aldehydes/ketones, indolyl methanols, etc. as well as the use of some specific compounds as starting materials to achieve the synthesis of this invaluable molecule. By encapsulating the latest developments in this field, this review provides insights into the expanding horizons of bis(indolyl)methane synthesis.

Aryl Hydrocarbon Receptor Activation Coordinates Mouse Small Intestinal Epithelial Cell Programming

In the face of mechanical, chemical, microbial, and immunologic pressure, intestinal homeostasis is maintained through balanced cellular turnover, proliferation, differentiation, and self-renewal. Here, we present evidence supporting the role of the aryl hydrocarbon receptor (AHR) in the adaptive reprogramming of small intestinal gene expression, leading to altered proliferation, lineage commitment, and remodeling of the cellular repertoire that comprises the intestinal epithelium to promote intestinal resilience. Ahr gene/protein expression and transcriptional activity exhibit marked proximal^HI to distal^LO and crypt^HI to villi^LO gradients. Genetic ablation of Ahr impairs commitment/differentiation of the secretory Paneth and goblet cell lineages and associated mucin production, restricts expression of secretory/enterocyte differentiation markers, and increases crypt-associated proliferation and villi-associated enterocyte luminal exfoliation. Ahr^-/- mice display a decrease in intestinal barrier function. Ahr^+/+ mice that maintain a diet devoid of AHR ligands intestinally phenocopy Ahr^-/- mice. In contrast, Ahr^+/+ mice exposed to AHR ligands reverse these phenotypes. Ligand-induced AHR transcriptional activity positively correlates with gene expression (Math1, Klf4, Tff3) associated with differentiation of the goblet cell secretory lineage. Math1 was identified as a direct target gene of AHR, a transcription factor critical to the development of goblet cells. These data suggest that dietary cues, relayed through the transcriptional activity of AHR, can reshape the cellular repertoire of the gastrointestinal tract.

Syntheses and biological effects of natural Morinda lactone and derivatives

2-Caffeoyl-3-ketohexulofuranosonic acid γ-lactone (morinda lactone; 1a), a natural constituent of Morinda citrifolia L. (Rubiaceae), and eight derivatives with variance in the aryl residue were synthesised by Tsuji-Trost allylation of vitamin C acetonide with the respective aryl allyl alcohol. They were screened for antibiotic activities and for effects on the growth and persistence of microbial biofilms. Some derivatives were active against biofilms of S. aureus or C. albicans at concentrations not toxic to these microorganisms or mammalian cells.

Dynamic Modeling of Indole Glucosinolate Hydrolysis and Its Impact on Auxin Signaling

Plants release chemicals to deter attackers. Arabidopsis thaliana relies on multiple defense compounds, including indol-3-ylmethyl glucosinolate (I3G), which upon hydrolysis initiated by myrosinase enzymes releases a multitude of bioactive compounds, among others, indole-3-acetonitrile and indole-3-acetoisothiocyanate. The highly unstable isothiocyanate rapidly reacts with other molecules. One of the products, indole-3-carbinol, was reported to inhibit auxin signaling through binding to the TIR1 auxin receptor. On the contrary, the nitrile product of I3G hydrolysis can be converted by nitrilase enzymes to form the primary auxin molecule, indole-3-acetic acid, which activates TIR1. This suggests that auxin signaling is subject to both antagonistic and protagonistic effects of I3G hydrolysis upon attack. We hypothesize that I3G hydrolysis and auxin signaling form an incoherent feedforward loop and we build a mathematical model to examine the regulatory network dynamics. We use molecular docking to investigate the possible antagonistic properties of different I3G hydrolysis products by competitive binding to the TIR1 receptor. Our simulations reveal an uncoupling of auxin concentration and signaling, and we determine that enzyme activity and antagonist binding affinity are key parameters for this uncoupling. The molecular docking predicts that several I3G hydrolysis products strongly antagonize auxin signaling. By comparing a tissue disrupting attack - e.g., by chewing insects or necrotrophic pathogens that causes rapid release of I3G hydrolysis products - to sustained cell-autonomous I3G hydrolysis, e.g., upon infection by biotrophic pathogens, we find that each scenario gives rise to distinct auxin signaling dynamics. This suggests that plants have different defense versus growth strategies depending on the nature of the attack.

Subglutinol A, an immunosuppressive α-pyrone diterpenoid from Fusarium subglutinans, acts as an estrogen receptor antagonist

Subglutinol A is an immunosuppressive α-pyrone diterpenoid isolated from Fusarium subglutinans that exhibits osteogenic activity. Several non-steroid mycotoxins isolated from various strains of Fusarium fungi exhibit female steroid hormone activities. In this study, we characterized the estrogenic activity of subglutinol A (1). Subglutinol A blocked the 17β-estradiol-induced activation of reporter plasmids and endogenous estrogen-responsive target genes in a dose-dependent manner and efficiently destabilized ER proteins as shown using the estrogen receptor antagonist ICI 182,780. Subglutinol A also displaced the specific binding of [(3)H]17β-estradiol from ER in MCF-7 whole-cell ligand binding assays. These data demonstrate the potential of subglutinol A as an ER antagonist though its competition with 17β-estradiol for direct ER association.

Antioxidative properties of ascorbigen in using multiple antioxidant assays

The antioxidative properties of ascorbigen, one of the major indole-derived compounds of Brassica vegetables, were systematically evaluated using multiple assay systems with comparison to the well-known antioxidants ascorbic acid and Trolox. We first performed assays using model radicals, DPPH radical, galvinoxyl radical, and ABTS radical cation (ABTS(•+)). Ascorbigen showed stronger activity than that of ascorbic acid in the ABTS(•+)-scavenging assay but showed no activity in the DPPH radical- and galvinoxyl radical-scavenging assays. In the ABTS(•+)-scavenging assay, the indole moiety of ascorbigen contributed to scavenging of the radicals to produce indole-3-aldehyde as one of the final reaction products. The activity of ascorbigen was then evaluated by an oxygen radical absorbance capacity assay and an oxidative hemolysis inhibition assay using physiologically relevant peroxyl radicals, AAPH-derived radicals. Ascorbigen showed much stronger antioxidant activity than did ascorbic acid and Trolox. Therefore, antioxidant activity of ascorbigen might be more beneficial than has been thought for daily health care.

Restoration by Dietary Glutamine of Reduced Tumor Necrosis Factor Production in a Low-Protein-Diet-Fed Rat Model

Tumor necrosis factor-alpha (TNF) production by peritoneal macrophages and its dietary modification were investigated by using rats fed on a low-protein diet. The rats were given a 20% casein (control) diet or a 3% casein diet for 21 days, and TNF production was measured in activated macrophages of these animals. TNF production was significantly lower in macrophages from rats fed on the low-protein diet than that in macrophages from rats fed on the control diet. Oral administration of a cabbage extract, a known modulator of TNF production, to the low-protein-diet-fed rats significantly enhanced TNF production by macrophages. Glutamine supplementation to the low-protein diet significantly enhanced TNF production as well as TNF mRNA expression. These results indicate that the 3%-casein-diet-fed rat would be useful as a model for reduced TNF production in protein malnutrition. These results also suggest that glutamine administration restored the reduced TNF production associated with protein malnutrition.

Glucosinolates, myrosinase hydrolysis products, and flavonols found in rocket (Eruca sativa and Diplotaxis tenuifolia)

Rocket species have been shown to have very high concentrations of glucosinolates and flavonols, which have numerous positive health benefits with regular consumption. This review highlights how breeders and processors of rocket species can utilize genomic and phytochemical research to improve varieties and enhance the nutritive benefits to consumers. Plant breeders are increasingly looking to new technologies such as HPLC, UPLC, LC-MS, and GC-MS to screen populations for their phytochemical content to inform plant selections. This paper collates the research that has been conducted to date in rocket and summarizes all glucosinolate and flavonol compounds identified in the species. The paper emphasizes the importance of the broad screening of populations for phytochemicals and myrosinase degradation products, as well as unique traits that may be found in underutilized gene bank resources. This review also stresses that collaboration with industrial partners is becoming essential for long-term plant breeding goals through research.

Multiple therapeutic and preventive effects of 3,3'-diindolylmethane on cancers including prostate cancer and high grade prostatic intraepithelial neoplasia

Cruciferous vegetables belong to the plant family that has flowers with four equal-sized petals in the pattern of a crucifer cross. These vegetables are an abundant source of dietary phytochemicals, including glucosinolates and their hydrolysis products such as indole-3-carbinol (I3C) and 3,3′-diindolylmethane (DIM). By 2013, the total number of natural glucosinolates that have been documented is estimated to be 132. Recently, cruciferous vegetable intake has garnered great interest for its multiple health benefits such as anticancer, antiviral infections, human sex hormone regulation, and its therapeutic and preventive effects on prostate cancer and high grade prostatic intraepithelial neoplasia (HGPIN). DIM is a hydrolysis product of glucosinolates and has been used in various trials. This review is to provide an insight into the latest developments of DIM in treating or preventing both prostate cancer and HGPIN.

Crystal structure of ethyl 5-chloro-2-indolecarboxylate, C11H10ClNO2

C11H10ClNO2, monoclinic, P21/n (no. 14), a = 10.570(3) Å, b = 5.617(2) Å, c = 18.091(5) Å, β = 105.681(4)°, V = 1034.0 Å3, Z = 4, Rgt(F) = 0.0397, wRref(F2) = 0.1072, T = 153 K.

Health benefits and possible risks of broccoli - an overview

Chemopreventive effects of broccoli, a highly valued vegetable, have been known for a long time. Several studies have demonstrated that broccoli might be beneficial by reducing the risk for the development of certain forms of cancer. These effects are generally attributed to glucosinolate-derived degradation products like isothiocyanates and indoles which are formed by the hydrolytic action of plant myrosinase and/or glucosidases deriving from the human microbial flora. However, recent in vitro and experimental animal studies indicate that broccoli, its extracts and the glucosinolate-derived degradation products might also have undesirable effects, especially genotoxic activities. However, the relevance of the genotoxic activities to human health is not known yet. This paper gives an overview on genotoxic, anti-genotoxic/chemopreventive, nutritive and antinutritive properties of broccoli, its ingredients and their degradation products. A qualitative comparison of the benefit and risk of broccoli consumption benefit-risk assessment shows that the benefit from intake in modest quantities and in processed form outweighs potential risks. For other preparations (fortified broccoli-based dietary supplements, diets with extraordinary high daily intake, consumption as a raw vegetable) further studies both for potential risks and beneficial effects are needed in order to assess the benefit and risk in the future.

Huitlacoche (corn smut), caused by the phytopathogenic fungus Ustilago maydis, as a functional food

BACKGROUND

In recent years the need has arisen to study and develop (or re-discover) foods that have nutritional characteristics as well as specific functions, such as improving health and/or reducing the risk of disease. For this reason knowledge of the nutritional value of food is important to promote greater consumer acceptance. In Mexico huitlacoche (also, cuitlacoche) has traditionally been prized as a delicacy since the time of the Aztecs and is currently being studied as a potential functional food and as a producer of natural bioactive substances that are used in fortifying foods.

AIMS

To present an updated review about the properties of the huitlacoche (corn smut) as functional food.

METHODS

A bibliographic search was performed and data were discussed.

RESULTS

The data of the works reviewed here show that huitlacoche contains many compounds that confer to it unique organoleptic and nutraceutical characteristics.

CONCLUSIONS

The content of bioactive substances in huitlacoche supports the proposal that this is a good functional food as well as producer of compounds to enrich other foods.

The p38 MAPK pathway is critical for 5,5'-dibromodiindolylmethane-induced apoptosis to prevent oral squamous carcinoma cells

Cruciferous vegetables contain isothiocyanates including diindolylmethane (DIM) that exhibit cancer chemopreventive effects. We developed a series of synthetic ring-substituted DIM analogs including 5,5'-dibromoDIM that exhibited better inhibitory activity in breast and colon cancer cells than DIM. In this study, we investigated whether 5,5'-dibromoDIM inhibits the proliferation of KB and YD-10B oral squamous carcinoma cell lines. 5,5'-dibromoDIM decreased the cell survival and inhibited the growth of oral cancer cells. Exposure of KB and YD-10B cells to 5,5'-dibromoDIM induced caspase-dependent apoptosis evidenced by poly-ADP ribose polymerase cleavage, accumulation of sub-G1 population, and nuclear condensation and fragmentation. In addition, apoptotic cell death was correlated with damage to the mitochondrial membrane potential through a decrease in the level of Bcl-2 protein expression. Mechanistic studies showed that mitochondria-dependent apoptosis induced by 5,5'-dibromoDIM was mediated by the p38 mitogen-activated protein kinase pathway but not the ERK1/2 and JNK pathway. These results highlight 5,5'-dibromoDIM as an important chemopreventive agent for the clinical treatment of oral cancer through the p38 mitogen-activated protein kinase pathway.

Chemical evaluation and sensory quality of sauerkrauts obtained by natural and induced fermentations at different NaCl levels from Brassica oleracea Var. capitata Cv. Bronco grown in eastern Spain. Effect of storage

The aim of the present work was to optimize fermentation conditions of white cabbage ( Brassica oleracea L. var. capitata cv. Bronco) grown in winter in eastern Spain. The influence of two salt concentrations (0.5 and 1.5% NaCl) in combination with spontaneous or induced cabbage fermentation on the content of ascorbigen (ABG) and vitamin C as well as on the sensory quality of sauerkraut was investigated. The effect of storage at 4 degrees C for 1-3 months was also studied. ABG content increased from 14 micromol/100 g of dm in raw cabbage to 63-137 micromol/100 g of dm during fermentation, whereas vitamin C decreased from 354 to 236-277 mg/100 g of dm, and the variations depended on the fermentation conditions. Sauerkrauts obtained by Leuconostoc mesenteroides at 0.5% NaCl showed the highest ABG content and a large amount of vitamin C. Refrigeration for 1-3 months led to a reduction of ABG and vitamin C levels, but L. mesenteroides sauerkrauts presented considerable amounts of both compounds at the end of the storage period (74-82 micromol/100 g of dm and 33-44 mg/100 g of dm, respectively), higher than those found with Lactobacillus plantarum and the mixed starter culture before storage. Experimental sauerkrauts presented better organoleptic properties than the commercial products, and no differences in overall acceptability were found among natural fermentations and those performed with starter cultures. These results suggest than low-salted sauerkraut produced with L. mesenteroides provided highly beneficial antioxidant and anticarcinogenic compounds and low sodium content, which is in accordance with the general trend in industrialized countries of reducing the salt level of foods to prevent cardiovascular diseases.

Glucosinolates in Brassica vegetables: the influence of the food supply chain on intake, bioavailability and human health

Glucosinolates (GLSs) are found in Brassica vegetables. Examples of these sources include cabbage, Brussels sprouts, broccoli, cauliflower and various root vegetables (e.g. radish and turnip). A number of epidemiological studies have identified an inverse association between consumption of these vegetables and the risk of colon and rectal cancer. Animal studies have shown changes in enzyme activities and DNA damage resulting from consumption of Brassica vegetables or isothiocyanates, the breakdown products (BDP) of GLSs in the body. Mechanistic studies have begun to identify the ways in which the compounds may exert their protective action but the relevance of these studies to protective effects in the human alimentary tract is as yet unproven. In vitro studies with a number of specific isothiocyanates have suggested mechanisms that might be the basis of their chemoprotective effects. The concentration and composition of the GLSs in different plants, but also within a plant (e.g. in the seeds, roots or leaves), can vary greatly and also changes during plant development. Furthermore, the effects of various factors in the supply chain of Brassica vegetables including breeding, cultivation, storage and processing on intake and bioavailability of GLSs are extensively discussed in this paper.

Diindolylmethane inhibits cervical dysplasia, alters estrogen metabolism, and enhances immune response in the K14-HPV16 transgenic mouse model

This study was designed to establish whether 3,3'-diindolylmethane (DIM) can inhibit cervical lesions, alter estrogen metabolism in favor of C-2 hydroxylation, and enhance immune function in the K14-HPV16 transgenic mouse model. Mice were bred, genotyped, implanted with E(2) pellets (0.25 mg/90-day release) under anesthesia, and divided into groups. Wild-type and transgenic mice were given either AIN76A diet alone or with 2,000 ppm DIM for 12 weeks. Blood and reproductive tracts were obtained. Blood was analyzed for estrogen metabolites and IFN-gamma. The cervical transformation zone was sectioned and stained for histology. Estradiol C-2 hydroxylation and serum IFN-gamma levels were significantly increased over controls in wild-type and transgenic mice receiving DIM. In wild-type mice without DIM, hyperplasia of the squamous epithelium was observed. Wild-type mice fed DIM displayed a normal thin epithelium. In transgenic mice without DIM, epithelial cell projections into the stroma (papillae) were present. An additional degree of nuclear anaplasia in the stratum espinosum was observed. Dysplastic cells were present. Transgenic mice fed DIM displayed some mild hyperplasia of the squamous epithelium. DIM increases estrogen C-2 hydroxylation in this model. Serum INF-gamma was increased, indicating increased immune response in the DIM-fed animals. Histopathology showed a marked decrease in cervical dsyplasia in both wild-type and transgenic mice, indicating that DIM delays or inhibits the progression from cervical dysplasia to cervical cancer. Using the K14-HPV16 transgenic mouse model, we have shown that DIM inhibits the development of E6/E7 oncogene-induced cervical lesions.

Pharmacological and biological screening of ascorbigen: protection against glucose-induced endothelial cell toxicity

Cruciferous vegetables contain significant amounts of ascorbigen and related substances with known molecular structures. This study tested the hypothesis that ascorbigen demonstrates antioxidant properties and protects human umbilical cord endothelial cells against hyperglycemic toxicity in vitro. It was observed that ascorbigen, in micromolar concentrations, protected against endothelial cell death from glucose toxicity. Additionally, ascorbigen at 3.0 mm shifted the concentration response curve of l-phenylephrine to the right, with a reduction in the maximal contractile effects of the agonist. This action was not related to alpha-adrenoceptor blockade. Ascorbigen also relaxed the vascular tone induced by l-phenylephrine, which is not mediated by an endothelial cell nitric oxide-dependent mechanism. On the guinea-pig ileum, the spasmogenic effects of carbachol, histamine and serotonin were reduced in the presence of 3 mM ascorbigen. Spasm of the gut induced by the acetylcholinesterase inhibitor, physostigmine, was antagonized by ascorbigen with an IC50 of 286 microM. This natural product also has a weak antiparasitic activity. The cytoprotective effects of ascorbigen may be highly relevant in the optimum physiological regulation of the function and the therapeutic value of this substance in disease settings needs to be further investigated.

Antigenotoxic, antioxidant and lymphocyte induction effects produced by pteropodine

Pteropodine is a heterohimbine-type oxindole alkaloid specifically isolated from 'Cat's claw' (Uncaria tomentosa), a plant that has shown cytostatic, anti-inflammatory and antimutagenic properties and is used in traditional medicine to cure a number of diseases. In this report, we studied the ability of pteropodine to decrease the rate of sister-chromatid exchanges and micronucleated polychromatic erythrocytes in mice administered doxorubicin. We also determined its capacity to induce lymphocyte production in mice as well as its free radical scavenging potential by applying the DPPH assay. We found pteropodine (100-600 mg/kg) to significantly decrease the frequency of sister-chromatid exchanges and micronucleated polychromatic erythrocytes in mice administered with 10 mg/kg of doxorubicin. Furthermore, we determined that pteropodine partially corrected bone marrow cytotoxicity induced by doxorubicin, as it showed an improvement in the rate of polychromatic erythrocytes. Besides, 600 mg/kg of pteropodine increased 25.8% of the production of lymphocytes over the control value along a 96-hr assay, and it exhibited a strong capacity to trap the DPPH-free radical (98.26% with 250 microg/ml). Our results establish that pteropodine is an effective antimutagen in the model used, and suggest that pteropodine deserves further research in the area of cell protective potential and its mechanism of action.

Cancer chemotherapy with indole-3-carbinol, bis(3'-indolyl)methane and synthetic analogs

Indole-3-carbinol (I3C) conjugates are phytochemicals expressed in brassica vegetables and have been associated with the anticancer activities of vegetable consumption. I3C and its metabolite bis(3'-indolyl)methane (DIM) induce overlapping and unique responses in multiple cancer cell lines and tumors, and these include growth inhibition, apoptosis and antiangiogenic activities. The mechanisms of these responses are complex and dependent on cell context. I3C and/or DIM activate or inactivate multiple nuclear receptors, induce endoplasmic reticulum stress, decrease mitochondrial membrane potential, and modulate multiple signaling pathways including kinases. DIM has been used as a template to synthesize a series of 1,1-bis(3'indolyl)-1-(substituted aromatic)methanes (i.e. C-DIMs) which are also cytotoxic to cancer cells and tumors. Some of the effects of C-DIMs resemble those reported for DIM analogs; however, structure-activity studies with the aromatic ring has resulted in generation of highly unique receptor agonists. For example, p-trifluoromethylphenyl, p-t-butylphenyl and p-biphenyl analogs activate peroxisome proliferator-activated receptor gamma (PPARgamma), and p-methoxyphenyl and p-phenyl compounds activate nerve growth factor-induced-Balpha (NGFI-Balpha, Nur77) orphan nuclear receptor. The effects of C-DIMs on PPARgamma and Nur77 coupled with their receptor-independent activities has resulted in the development of a novel group of multi-targeted anticancer drugs with excellent potential for clinical treatment of cancer.

1,1-bis(3'-indolyl)-1-(p-methoxyphenyl)methane activates Nur77-independent proapoptotic responses in colon cancer cells

1,1-Bis(3'-indolyl)-1-(p-methoxyphenyl)methane (DIM-C-pPhOCH(3)) is a methylene-substituted diindolylmethane (C-DIM) analog that activates the orphan receptor nerve growth factor-induced-Balpha (NGFI-Balpha, Nur77). RNA interference studies with small inhibitory RNA for Nur77 demonstrate that DIM-C-pPhOCH(3) induces Nur77-dependent and -independent apoptosis, and this study has focused on delineating the Nur77-independent proapoptotic pathways induced by the C-DIM analog. DIM-C-pPhOCH(3) induced caspase-dependent apoptosis in RKO colon cancer cells through decreased mitochondrial membrane potential which is accompanied by increased mitochondrial bax/bcl-2 ratios and release of cytochrome c into the cytosol. DIM-C-pPhOCH(3) also induced phosphatidylinositol-3-kinase-dependent activation of early growth response gene-1 which, in turn, induced expression of the proapoptotic nonsteroidal anti-inflammatory drug-activated gene-1 (NAG1) in RKO and SW480 colon cancer cells. Moreover, DIM-C-pPhOCH(3) also induced NAG-1 expression in colon tumors in athymic nude mice bearing RKO cells as xenografts. DIM-C-pPhOCH(3) also activated the extrinsic apoptosis pathway through increased phosphorylation of c-jun N-terminal kinase which, in turn, activated C/EBP homologous transcription factor (CHOP) and death receptor 5 (DR5). Thus, the effectiveness of DIM-C-pPhOCH(3) as a tumor growth inhibitor is through activation of Nur77-dependent and -independent pathways.

Nur77 agonists induce proapoptotic genes and responses in colon cancer cells through nuclear receptor-dependent and nuclear receptor-independent pathways

Nerve growth factor-induced Balpha (NGFI-Balpha, Nur77) is an orphan nuclear receptor with no known endogenous ligands; however, recent studies on a series of methylene-substituted diindolylmethanes (C-DIM) have identified 1,1-bis(3'-indolyl)-1-(phenyl)methane (DIM-C-Ph) and 1,1-bis(3'-indolyl)-1-(p-anisyl)methane (DIM-C-pPhOCH3) as Nur77 agonists. Nur77 is expressed in several colon cancer cell lines (RKO, SW480, HCT-116, HT-29, and HCT-15), and we also observed by immunostaining that Nur77 was overexpressed in colon tumors compared with normal colon tissue. DIM-C-Ph and DIM-C-pPhOCH3 decreased survival and induced apoptosis in RKO colon cancer cells, and this was accompanied by induction of tumor necrosis factor-related apoptosis-inducing ligand (TRAIL) protein. The induction of apoptosis and TRAIL by DIM-C-pPhOCH3 was significantly inhibited by a small inhibitory RNA for Nur77 (iNur77); however, it was evident from RNA interference studies that DIM-C-pPhOCH3 also induced Nur77-independent apoptosis. Analysis of DIM-C-pPhOCH3-induced gene expression using microarrays identified several proapoptotic genes, and analysis by reverse transcription-PCR in the presence or absence of iNur77 showed that induction of programmed cell death gene 1 was Nur77 dependent, whereas induction of cystathionase and activating transcription factor 3 was Nur77 independent. DIM-C-pPhOCH3 (25 mg/kg/d) also inhibited tumor growth in athymic nude mice bearing RKO cell xenografts. These results show that Nur77-active C-DIM compounds represent a new class of anti-colon cancer drugs that act through receptor-dependent and receptor-independent pathways.

Changes in the content of health-promoting compounds and antioxidant activity of broccoli after domestic processing

The effect of water- and steam-cooking on the content of vitamin C, polyphenols, carotenoids, tocopherols and glucosinolates, as well as on the antioxidant activity of broccoli, are reported. Flavonoids, phenolic acids, vitamins C and E, beta-carotene, lutein, and glucosinolates in domestically processed broccoli were quantified using high-performance liquid chromatography (HPLC) methods; total polyphenols were determined with Folin-Ciocalteu reagent. The antioxidant capacities of broccoli extracts were evaluated using the Trolox equivalent antioxidant capacity (TEAC) and 2,2-diphenyl-1-picrylhydrazyl (DPPH) methods. The results indicated that steam-cooking of broccoli results in an increase in polyphenols, as well as the main glucosinolates and their total content as compared with fresh broccoli, whereas cooking in water has the opposite effect. Steam-cooking of broccoli has no influence on vitamin C, whereas cooking in water significantly lowers its content. Both, water- and steam-cooking of broccoli results in an increase in beta-carotene, lutein, and alpha- and gamma-tocopherols as compared with fresh broccoli. Similar effects of steaming and water-cooking of broccoli on their antioxidant activity were observed.

Inhibition of breast cancer cell growth and induction of cell death by 1,1-bis(3'-indolyl)methane (DIM) and 5,5'-dibromoDIM

1,1-Bis(3'-indolyl)methane (DIM) and the 5,5'-dibromo ring substituted DIM (5,5'-diBrDIM) inhibited growth of MCF-7 and MDA-MB-231 breast cancer cells, and IC50 values were 10-20 and 1-5 microM, respectively, in both cell lines. DIM and 5,5'-diBrDIM did not induce p21 or p27 protein levels or alter expression of Sp1 or Sp3 proteins in either cell line. In contrast, 10 microM 5,5'-diBrDIM downregulated cyclin D1 protein in MCF-7 and MDA-MB-231 cells 12 and 24 h after treatment. DIM (20 microM) also decreased cyclin D1 in MCF-7 (24 h) and MDA-MB-231 (12 h), and the DIM/5,5'-diBrDIM-induced degradation of cyclin D1 was blocked by the proteasome inhibitor MG132. Both DIM and 5,5'-diBrDIM induced apoptosis in MCF-7 cells and this was accompanied by decreased Bcl-2, release of mitochondrial cytochrome c, and decreased mitochondrial membrane potential as determined by the red/green fluorescence of JC-1. DIM and 5,5'-diBrDIM induced extensive necrosis in MDA-MB-231 cells; however, this was accompanied by decreased mitochondrial membrane potential primarily in cells treated with 5,5'-diBrDIM but not DIM. Thus, DIM and 5,5'-diBrDIM induce cell death in MCF-7 and MDA-MB-231 cells by overlapping and different pathways, and the ring-substituted DIM represents a novel class of uncharged mitochondrial poisons that inhibit breast cancer cell and tumor growth.

Glucosinolate derivatives in stored fermented cabbage

The research focused on the glucosinolate (GLS) breakdown products formed during the fermentation of cabbage. A relationship between the contents of degradation products in fermented cabbage and native GLS in raw cabbage was investigated. The effect of fermented cabbage storage on the contents of individual compounds was also assayed. Ascorbigen formed from one of the degradation products of glucobrassicin (indole GLS) was found to be a dominating compound in fermented cabbage. Irrespective of the time of fermented cabbage storage, the content of ascorbigen reached approximately 14 micromol/100 g. Neither the content of isothiocyanates, the major degradation products of aliphatic GLS, nor that of cyanides exceeded 2.5 microM. Storage of cabbage caused periodical increases and decreases in the contents of cyanides and consequent declines in the contents of isothiocyanates. The highest relative contents (expressed as a percentage of the native GLS content) of degradation products--ranging from >70 to 96%--were reported for the products of glucoraphanin degradation, whereas the lowest-- <5% --were reported for the products of sinigrin degradation.

A new class of peroxisome proliferator-activated receptor γ (PPARγ) agonists that inhibit growth of breast cancer cells: 1,1-Bis(3′-indolyl)-1-(p-substituted phenyl)methanes

1,1-Bis(3′-indolyl)-1-(p-trifluoromethylphenyl)methane (DIM-C-pPhCF3) and several p-substituted phenyl analogues have been investigated as a new class of peroxisome proliferator-activated receptor γ (PPARγ) agonists. Structure-activity studies in PPARγ-dependent transactivation assays in MCF-7 breast cancer cells show that 5–20 μm concentrations of compounds containing p-trifluoromethyl, t-butyl, cyano, dimethylamino, and phenyl groups were active, whereas p-methyl, hydrogen, methoxy, hydroxyl, or halogen groups were inactive as PPARγ agonists. Induction of PPARγ-dependent transactivation by 15-deoxy-Δ12,14-prostaglandin J2 (PGJ2) and DIM-C-pPhCF3 was inhibited in MCF-7 cells cotreated with the PPARγ-specific antagonist N-(4′-aminopyridyl)-2-chloro-5-nitrobenzamide. In mammalian two-hybrid assays, DIM-C-pPhCF3 and PGJ2 (5–20 μm) induced interactions of PPARγ with steroid receptor coactivator (SRC) 1, SRC2 (TIFII), and thyroid hormone receptor-associated protein 220 but not with SRC3 (AIB1). In contrast, DIM-C-pPhCF3, but not PGJ2, induced interactions of PPARγ with PPARγ coactivator-1. C-substituted diindolylmethanes inhibit carcinogen-induced rat mammary tumor growth, induce differentiation in 3T3-L1 preadipocytes, inhibit MCF-7 cell growth and G0/G1-S phase progression, induce apoptosis, and down-regulate cyclin D1 protein and estrogen receptor α in breast cancer cells. These compounds are a novel class of synthetic PPARγ agonists that induce responses in MCF-7 cells similar to those observed for PGJ2.

Induction of tumor necrosis factor production and antitumor effect by cabbage extract

The effect of cabbage extract on the production of tumor necrosis factor and its implication in the antitumor effect were examined in vitro and in vivo. Cabbage extract stimulated the production of tumor necrosis factor by rat spleen cells and showed cytotoxic activity in a rat ascites hepatoma cell line (AH109A) when hepatoma cells were cultured with cabbage-stimulated spleen cells. When the extract was adminstered orally to AH109A-bearing rats in combination with lipopolysaccharide injection, the hepatoma weights were reduced to one-half of the vehicle control. The cytotoxic activity of tumor-infiltrating macrophages was induced by simultaneous treatment with cabbage extract and lipopolysaccharide. These results indicate that cabbage extract contains macrophage-stimulating component(s) and can implement the antitumor effect by stimulating the cytotoxicity of tumor-infiltrating macrophages.

The micronutrient indole-3-carbinol: implications for disease and chemoprevention

This review provides a historical perspective for the development of indole-3-carbinol (I-3-C) as a chemopreventive or therapeutic agent. Early experiments in animal models clearly showed that feeding cruciferous vegetables reduced the incidence of chemical carcinogenesis. Excitement was generated by the finding that these vegetables contained a high content of indole-containing compounds, and I-3-C could by itself inhibit neoplasia. The mechanism of action was linked primarily to the ability of I-3-C and derived substances to induce mixed-function oxidases and phase II antioxidant enzymes by binding and activating the aryl hydrocarbon receptor. Most of the literature on chemoprotection by dietary indole compounds relates to this mechanism of action. Other mechanisms, however, are notable for this class of compounds, including their ability to act as radical and electrophile scavengers; the various ascorbate conjugates of I-3-C (ascorbigens) may be important in this regard. Exciting recent findings have demonstrated that I-3-C and its reaction products can affect cellular signaling pathways, regulate the cell cycle, and decrease tumor cell properties related to metastasis. It does not appear that I-3-C per se is the primary active compound in chemoprotection or chemoprevention. Rather, I-3-C and ascorbate provide the parent compounds for the formation of a myriad of nonenzymatic reaction products that have strong biological potency. We conclude with our thoughts regarding the current status and future directions for the use of I-3-C and related compounds.

The formation of 2-hydroxy-4-hydroxymethyl-3-(indol-3-yl)-cyclopent-2-enone derivatives from ascorbigens

A facile preparation is described of 3-(indol-3-yl)-2-hydroxy-4-hydroxymethylcyclopent-2-enone and its N-derivatives in 15-40% yields by the degradation of ascorbigen or its N-derivatives in a warm solution of L-ascorbic acid through a sequential domino reaction. The same cyclopentenone derivatives were obtained in 30-40% yields by the condensation of (N-alkylindol-3-yl)glycolic acids with ascorbic acid. 2,6-Dihydroxy-1-(indol-3-yl)hexa-1,4-diene-3-one and 2-hydroxy-4-hydroxymethyl-5-(indol-3-yl)cyclopent-2-enone were identified as intermediates in this reaction.

Possible Role of Formaldehyde in the Apoptotic and Mitotic Effect of 1-Methyl-Ascorbigen

PC-3 human prostate carcinoma cells were treated with 100 mg/ml 1-methyl-ascorbigen (Me-Asc). This treatment resulted in a significant decrease in tumor cell number in parallel with an increase in apoptotic cells. The formaldehyde (HCHO) level in the culture medium was also increased. Dimedone (Di), a known capture molecule forming formal-demethone with HCHO, applied simultaneously with Me-Asc in 10 mg/ml doses diminished the apoptosis-inducing effect of Me-Asc. The possible role of in situ generated HCHO in the induction of apoptosis is discussed.

Estrogenic effects of extracts from cabbage, fermented cabbage, and acidified brussels sprouts on growth and gene expression of estrogen-dependent human breast cancer (MCF-7) cells

Cruciferous vegetable extracts from freeze-dried cabbage (FDC), freeze-dried fermented cabbage (FDS), and acidified Brussels sprouts (ABS) were prepared by exhaustive extraction with ethyl acetate. Estrogenic and antiestrogenic effects of these extracts were analyzed. To identify whether the extracts are potential estrogen receptor (ER) ligands that can act as agonists or antagonists, the binding affinity of extracts for the ER was measured using a competitive radiometric binding assay. The extracts bound with low affinity to the ER, and the relative binding affinity is estradiol > FDS > FDC > ABS. These extracts were evaluated for their estrogenic and antiestrogenic activities in estrogen-dependent human breast cancer (MCF-7) cells using as endpoints proliferation and induction of estrogen-responsive pS2 gene expression, which was analyzed using Northern blot assay. At low concentrations (5-25 ng/mL) all of the extracts reduced 1 nM estradiol-induced MCF-7 cell proliferation. Extracts at 25 ng/mL also inhibited estradiol-induced pS2 mRNA expression. At higher extract concentrations (50 ng/mL-25 microg/mL), however, increased proliferation in MCF-7 cells was observed. Similarly, expression of the pS2 gene was induced by higher extract concentrations (0.25-25 microg/mL). The pure estrogen antagonist, ICI 182,780, suppressed the cell proliferation induced by the extracts as well as by estradiol and also the induction of pS2 expression by the extracts. The ER subtype-selective activities of FDC and FDS were analyzed using a transfection assay in human endometrial adenocarcinoma (HEC-1) cells. FDS acted as an ERalpha-selective agonist while FDC fully activated both ER-alpha and ER-beta. Growth of the ER-negative MDA-231 cells was not affected by the extracts or by estradiol. This study demonstrates that cruciferous vegetable extracts act bifunctionally, like an antiestrogen at low concentrations and an estrogen agonist at high concentrations.

Determination of ascorbigens in autolysates of various Brassica species using supercritical fluid chromatography

A new method of analysis based on normal phase supercritical fluid chromatography (SFC) has been developed for investigation of ascorbigens [2-C-(indol-3-ylmethyl)-beta-L-xylo-3-hexulofuranosonic acid gamma-lactone derivatives]. This method has been adapted to preparative isolation and quantitative determinations of individual ascorbigens comprising ascorbigen, neoascorbigen, and 4-methoxyascorbigen. The structures of these compounds have been revealed from 1D ((1)H, (13)C) and 2D (COSY, HMQC, HMBC) NMR experiments. The developed SFC method had an acceptable linearity for the ascorbigens with correlation coefficients (R(2)) > 0.9995 (n = 10) in the range of 0.13-4.9 nmol injected, detection limits were below 13 pmol, retention time stabilities were excellent, and relative response factors have been determined. The SFC method has been used for determination of ascorbigens produced during autolysis of indol-3-ylmethylglucosinolates in various Brassica vegetables and rapeseed seedlings. Generally, 30-60% of the indol-3-ylmethylglucosinolates in the plants were transformed into ascorbigens, with the concentration in autolysates varying from 0.51 +/- 0.002 to 3.72 +/- 0.21 micromol/g of dry weight (DW) for ascorbigen, from 0.05 +/- 0.01 to 2.42 +/- 0.23 micromol/g of DW for neoascorbigen, and from 0.03 +/- 0.002 to 0.84 +/- 0.07 micromol/g of DW for 4-methoxyascorbigen.

Growing alliums and brassicas in selenium-enriched soils increases their anticarcinogenic potentials

The concentrating of essential minerals, vitamins, and bioactive phytochemicals into human foodstuffs is of vital importance in our rapidly expanding world. Selenium is an essential micronutrient which is currently receiving much publicity for its anticarcinogenic potentials. Unfortunately, this mineral is deficient in most soils worldwide, and as a result most geographical food chains contain highly inadequate amounts of selenium. Scientific evidence in now available which shows that common vegetable members of the allium genus, especially garlic, are seleniferous in that they readily uptake inorganic selenium from the soil and incorporate it into bioactive organic chemicals. The brassicas have also been found to be highly seleniferous in nature and to produce various seleno amino acids and potentially bioactive organic selenium-containing phytochemicals. Upon consumption by humans, these selenium phytochemicals, derived from both plant genus, show anticarcinogenic potentials. Due to the high concentrations of natural phytochemicals, and the additional assimilation of selenium, the commercial or small scale production of selenium-enriched brassicas and garlic is an excellent way of introducing anticarcinogenic phytochemicals into the human diet.

Modulation of cytochrome P-450 and glutathione S-transferase isoform expression in vivo by intact and degraded indolyl glucosinolates

Various dietary substances modulate the xenobiotic metabolism and may thereby protect against toxicity and carcinogenicity of food toxins. The effects of pure indolyl glucosinolates, which are present in cruciferous vegetables, on induction of specific cytochrome P-450 (CYP) and glutathione S-transferase (GST) isoforms have not been studied previously. In the present study, glucobrassicin (GB) and neoglucobrassicin (NeoGB) were purified from broccoli by use of a single-column method. Furthermore, a mixture containing 48% GB, 36% NeoGB, and 16% 4-methoxyglucobrassicin was obtained. The modulatory effects of the pure GB, NeoGB, and the mixture on activities and levels of hepatic CYP 1A, 2B1/2, and 2E1 and alpha- and mu-GST isoforms were investigated in male Wistar rats. The indolyl mixture was the most powerful and NeoGB the weakest inducer of microsomal hepatic CYP 1A1 protein and 7-ethoxyresorufin O-deethylase activity. Furthermore, intact indolyl glucosinolates were more powerful inducers than the in vitro myrosinase-degraded indolyl glucosinolates. The hepatic 7-methoxyresorufin O-deethylase activities, but not CYP 1A2 protein, were induced by pure GB, whereas the mixture and NeoGB showed only minor effects. Neither CYP 2B1/2 nor 2E1 was induced by the indolyl glucosinolates. None of the hepatic GST subunits analyzed, rGST A1/2, A3, or M3, was induced significantly by the purified indolyl glucosinolates.