Abstract:1. Both after ingestion of benzyl isothiocyanate (BITC), a compound with antibacterial properties, and after consumption of garden cress known to contain BITC, the metabolite N-acetyl-S-(N-benzylthiocarbamoyl)-L-cysteine was identified in the urine of volunteers by comparative chromatography. 2. The chemical structure of the metabolite was confirmed by elemental analysis and by comparison of the i.r. and 1H-n.m.r. spectra with those of the synthetic product. 3. On average 53.7% of the dose of BITC was excreted… Show more
“…This implies a high potential for membrane partitioning, enabling efficient absorption by passive diffusion. Indeed, numerous studies describing the absorption of structurally different GLS-HP in animal models [172, 173, 175, 177 -179] and in humans [180,181], showing the fast absorption as measured indirectly by urinary excretion. Ye et al [182] applied the cyclo-condensation method to the detection of dithiocarbamates in blood.…”
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.
“…This implies a high potential for membrane partitioning, enabling efficient absorption by passive diffusion. Indeed, numerous studies describing the absorption of structurally different GLS-HP in animal models [172, 173, 175, 177 -179] and in humans [180,181], showing the fast absorption as measured indirectly by urinary excretion. Ye et al [182] applied the cyclo-condensation method to the detection of dithiocarbamates in blood.…”
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.
“…The urinary excretion of ITC conjugates has been used to study the bioavailability of ITC, which appears to be quite high [5]. For example, when benzyl isothiocyanate (BITC) was administered orally to humans, 54% of the dose was recovered in the urine as BITC-NAC [6]. However, availability of ITCs from specific foods is influenced by preparation (i.e., raw versus cooked) and eating habit (i.e.…”
Section: Chemistry and Metabolism Of Itcsmentioning
To cite this version:Breeze E. Cavell, Sharifah S. Syed Alwi, Alison Donlevy, Graham Packham. Anti-angiogenic effects of dietary isothiocyanates; mechanisms of action and implications for human health. Biochemical Pharmacology, Elsevier, 2010, 81 (3) This is a PDF file of an unedited manuscript that has been accepted for publication. As a service to our customers we are providing this early version of the manuscript. The manuscript will undergo copyediting, typesetting, and review of the resulting proof before it is published in its final form. Please note that during the production process errors may be discovered which could affect the content, and all legal disclaimers that apply to the journal pertain. A c c e p t e d M a n u s c r i p t 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 Isothiocyanates and angiogenesis -3 -
AbstractIsothiocyanates (ITCs) are electrophilic compounds derived from plants and are thought to play a major role in the potential chemopreventive effects associated with high intake of cruciferous vegetables. ITCs are also being evaluated for chemotherapeutic activity in early phase clinical trials. In addition to their effects on carcinogen metabolism and cancer cell survival and proliferation, ITCs have been shown to effectively interfere with angiogenesis in vitro and in vivo. Angiogenesis is the development of a new blood supply from existing vasculature and is required for tumours to develop beyond a small size limit determined by the diffusion limit for oxygen. Inhibition of angiogenesis may play a key role in the potential chemopreventive/chemotherapeutic activity of ITCs. In this review we highlight recent data demonstrating that ITCs have anti-angiogenic activity and identify potential molecular targets for these effects, including hypoxia-inducible factor (HIF), nuclear factor B (NF-B), activator protein 1 (AP1) and tubulin. We also discuss these findings in light of the potential chemopreventive/chemotherapeutic effects of ITCs.
“…Thus, so far, only the isothiocyanate MA have been studied as urinary biomarkers of glucosinolate hydrolysis in vivo. This approach has provided a reasonable understanding of the overall uptake of isothiocyanates after consumption of brassica by human subjects (Mennicke et al 1988;Chung et al 1998). …”
Section: Digestive and Post-absorptive Fate Of Glucosinolates After Imentioning
The protective effects of brassica vegetables against cancer may be partly related to their glucosinolate content. Glucosinolates are hydrolysed by plant myrosinase following damage of plant tissue. Isothiocyanates are one of the main groups of metabolites of glucosinolates and are implicated in the preventive effect against cancer. During cooking of brassica the glucosinolate–myrosinase system may be modified as a result of inactivation of plant myrosinase, loss of enzymic cofactors such as epithiospecifier protein, thermal breakdown and/or leaching of glucosinolates and their metabolites or volatilisation of metabolites. Cooking brassica affects the site of release of breakdown products of glucosinolates, which is the upper gastrointestinal tract following consumption of raw brassica containing active plant myrosinase. After consumption of cooked brassica devoid of plant myrosinase glucosinolates are hydrolysed in the colon under the action of the resident microflora. Feeding trials with human subjects have shown that hydrolysis of glucosinolates and absorption of isothiocyanates are greater following ingestion of raw brassica with active plant myrosinase than after consumption of the cooked plant with denatured myrosinase. The digestive fate of glucosinolates may be further influenced by the extent of cell rupture during ingestion, gastrointestinal transit time, meal composition, individual genotype and differences in colonic microflora. These sources of variation may partly explain the weak epidemiological evidence relating consumption of brassica to prevention against cancer. An understanding of the biochemical changes occurring during cooking and ingestion of brassica may help in the design of more robust epidemiological studies to better evaluate the protective effects of brassica against cancer.
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