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ABSTRACT: Gas chromatography chemical ionization mass spectrometry has been found to possess advantages over gas chromatography electron impact mass spectrometry for the structural elucidation of glucosinolates (mustard oil glycosides), separated as the volatile per-trimethylsilyldesulpho derivates. The method has been applied to both mixtures of standard glucosinolates and also to extracts of plant tissue. The technique demonstrates the versatility of mass spectrometry in glucosinolate identification.
Biological Mass Spectrometry 04/2005; 8(6):278 - 282. · 3.41 Impact Factor
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ABSTRACT: Fruits and vegetables contain several classes of compounds that can potentially contribute to antioxidant activity, including vitamins, simple and complex phenolics, sulphur-containing compounds and glucosinolates. The glucosinolates are found in high concentration in many cruciferous vegetables, and it is well established that their breakdown products induce endogenous antioxidant defences such as quinone reductase and glutathione S-transferase in cells and in vivo. Despite the anticarcinogenic effect of these compounds in animal models, the direct antioxidant properties of this class of compounds have not been systematically studied. We therefore examined the free radical-scavenging properties of representative extracts and of purified glucosinolates from cruciferous vegetables, by measuring their effect on ascorbate- or NADPH/iron-induced peroxidation of human liver microsomes, ascorbate/iron-induced peroxidation on phospholipid liposomes, iron chelation and hydroxyl radical scavenging using the deoxyribose assay, total antioxidant potential using ABTS (2,2'-azinobis(3-ethyl-benzothiazoline-6-sulphonate)) and the bleomycin assay. Most of the extracts from cruciferous vegetables exhibited some antioxidant properties, although extracts from cooked Brussels sprouts increased the rate of microsomal lipid peroxidation. The effects in these assays were dependent upon processing and species of crucifer, and the glucosinolate content appeared to play a minor role in these effects, since purified glucosinolates exhibited only weak antioxidant properties. The total antioxidant activities of extracts from cooked and autolysed Brussels sprouts were identical within experimental error. This is probably due to the content of phenolics which is unaltered by autolysis, despite the differences between these samples in other assays especially NADPH-iron-induced lipid peroxidation of human liver microsomes. The results demonstrate that glucosinolates are unlikely to account for the direct antioxidant effects of extracts from cruciferous vegetables.
Free Radical Research 08/1996; 25(1):75-86. · 2.88 Impact Factor
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ABSTRACT: We have tested the ability of a representative range of dietary glucosinolates and their breakdown products, found in high concentrations in cruciferous vegetables, to act as blocking agents against carcinogenesis by inducing the activity of the anticarcinogenic phase II marker enzyme quinone reductase in murine hepa1c1c7 cells. Breakdown of glucosinolates was catalysed by the endogenous plant enzyme thioglucoside glucohydrolase at neutral and acid pH. Only two unmodified glucosinolates, p-hydroxybenzyl and 2-hydroxybut-3-enyl, significantly induced quinone reductase activity. However, after enzymic hydrolysis at near-neutral pH, some of the glucosinolates yielded breakdown products that significantly induced quinone reductase in the order: 3-methylsulphinylpropyl-->prop-2-enyl-->pent-4-enyl approximately 2-phenylethyl approximately benzyl-->all others tested. Incubation with myrosinase at acidic pH resulted in induction of quinone reductase activity by the hydrolysis products of only three of the tested glucosinolates:3-methylsulphinyl-propyl approximately 2-phenylethyl-->benzyl-->all others, activity due to the two alkenyl compounds being lost. The results show that the potential cancer-blocking action of both intact and thioglucoside glucohydrolase-treated glucosinolates, as assessed by induction of phase II enzyme activity, is dependent on the nature of the side chain of the parent glucosinolate.
Carcinogenesis 05/1995; 16(5):1191-4. · 5.70 Impact Factor
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ABSTRACT: Many plant secondary metabolites exhibit a wide range of dose-related physiological properties when included in the diet of animals and man. Within the brassica family, the glucosinolates, a group of sulphur-containing glucosides have been the subject of a vast amount of study and the effects of dietary inclusion of such compounds or their metabolites on the health of animals and man are briefly reviewed. Although excessive amounts of glucosinolates in animal feed formulations may reduce growth and performance as well as affecting thyroid, liver, and kidney function, there is little evidence of such effects in man. On the contrary, compounds derived from glucosinolates as a consequence of enzymic breakdown or metabolism have been shown to activate mechanisms which moderate or reverse carcinogenic processes. Such effects may contribute to the net anti-carcinogenic benefit attributed to these vegetables in numerous epidemiological studies.
Natural Toxins 02/1995; 3(4):233-7; discussion 242.
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ABSTRACT: Over 145 extracts of vegetables, fruits, herbs, spices and beverages which are consumed regularly in the European diet have been surveyed for potential anti-carcinogenic activity using an assay which measures the induction of NAD(P)H: (quinone acceptor) menadione oxidoreductase (quinone reductase, QR) activity in murine cells challenged with solutions of potential inducers. When appropriate the study has included extracts prepared from cooked and autolysed material. The results indicate that extracts of some brassicas, legumes (peas), lettuces, red pepper, grapefruit and some herbs including basil, tarragon and rosemary are inducers of QR activity. Inducing activity is strongly dependent on processing and on variety.
European Journal of Cancer Prevention 06/1994; 3(3):285-92. · 2.13 Impact Factor
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ABSTRACT: Significant induction of mixed-function-oxidase (MFO) activity was observed in the small intestines of rats within 4-6 hr of ingestion of a single meal containing a Brassica vegetable (cabbage). Intact Brussels sprouts and a fractionated methanol-water extract of Brussels sprouts induced similar degrees of MFO activity in the livers, and small and large intestines of rats. However, the residue left after extraction of the polar compounds did not induce MFO activity. Different amounts of the various naturally-occurring thioglycosides and glucosinolates were found in the intact Brussels sprouts and in the extract, but virtually none were found in the extracted residue. When glucusinolates that were found in Brussels sprouts (sinigrin, progoitrin, glucobrassicin and glucotropaeolin) were fed separately to rats, only the indole glucosinolate, glucobrassicin, induced MFO activity (causing induction in the small intestines of the rats). This is consistent with the inducing activity of the various hydrolysis products of this glucosinolate. This is the first study in which an attempt has been made to define the inducing compounds in Brassica vegetables by feeding the individual purified glucosinolates.
Food and Chemical Toxicology 06/1989; 27(5):289-93. · 3.00 Impact Factor
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The Analyst 11/1988; 113(10):1515-8. · 4.23 Impact Factor
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ABSTRACT: Glucosinolates are a group of secondary products commonly, but not exclusively, found in plants of the family Cruciferae. They give rise, upon enzymic hydrolysis, to a range of volatile, pungent and physiologically active compounds. Recently, particular attention has been focused upon those that are trytophan-derived--the indole glucosinolates (glucobrassicins). When chemically or enzymically hydrolysed these compounds give rise to a range of involatile indole compounds which have been implicated in the anti-carcinogenic and mixed-function-oxidase stimulatory activities of brassica vegetables. This review details the chemical and physiological properties of indole glucosinolates and their products and suggests possible areas for future research.
Food and Chemical Toxicology 02/1988; 26(1):59-70. · 3.00 Impact Factor
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ABSTRACT: Both white and Savoy-type cabbage added to a semi-purified diet at 25% dry weight and fed to rats ad lib. for 5 days significantly induced ethoxyresorufin (ERR) deethylation in the small and large intestine. Savoy cabbage also induced hepatic activity and, in general, exhibited a greater inducing effect than white cabbage. These enzyme-inducing effects were altered when the cabbage had been processed. The content of intact glucosinolate was greater in Savoy than in white cabbage. The indole glucosinolate (glucobrassicin) content of both types of cabbage was approximately halved by cooking but was unaffected by fermentation, whilst homogenization of Savoy cabbage led to the total disappearance of intact glucosinolates. Levels of the indole glucosinolate breakdown products ascorbigen and indole-3-carbinol were highest in homogenized cabbage, and ascorbigen levels were also higher in cooked than in fresh cabbage of either type. When added to the semi-purified diet and fed ad lib. to rats for 5 days, indole-3-carbinol was a potent inducer of hepatic ERR deethylation and cytochrome P-450 activity, but had much less effect in the intestine. Other glucobrassicin metabolites, diindolylmethane and indole-3-acetonitrile, also had some inducing effect in the liver but no effect in the intestine, while ascorbigen significantly induced ERR deethylation in the small and large intestine but had no effect on hepatic MFO activity.
Food and Chemical Toxicology 06/1987; 25(5):363-8. · 3.00 Impact Factor
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ABSTRACT: The content of individual glucosinolates in 32 samples of cabbage (representing 21 cultivars), 11 samples of Savoy cabbage (seven different cultivars), 33 samples of swede (16 cultivars) and nine samples of turnip (three cultivars) have been determined by gas chromatography. 2‐Propenyl, 3‐methylsulphinyl and 3‐indolylmethyl glucosinolates were the predominant compounds in both types of cabbage, with the Savoy cabbage showing a mean total glucosinolate content more than double that of white cabbage (209 vs. 90mg/100g fresh weight). The glucosinolate content of the swede and turnip samples was more complex, with 2‐hydroxy‐3‐butenyl‐glucosinolate predominating in swedes and this compound, 3‐butenyl‐and 2‐phenylethyl‐glucosinolates being the major components of turnip. The mean total glucosinolate contents of swede and turnip were 92 and 93 mg/100 g fresh weight. Compared to published data on American vegetables, the UK cabbage samples were much richer in glucosinolates and the UK swede and turnip samples poorer in glucosinolates. Swede rind was observed to be a particularly good source of indolyl glucosinolates, the anticarcinogenic properties of which are presently under investigation.
Food Additives & Contaminants. 07/1984; 1(3):289-296.
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Critical Reviews in Food Science and Nutrition 02/1983; 18(2):123-201. · 4.79 Impact Factor
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ABSTRACT: 1. The “fishy” taint of brown‐shelled eggs from susceptible birds due to the presence of trimethylamine following the feeding of rapeseed meal has been shown to be associated with the presence of sinapine in the rapeseed meal.
British Poultry Science 09/1977; 18(5):539-541. · 1.00 Impact Factor
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ABSTRACT: A modified gas liquid chromatography method has been developed to analyse the concentrations of indole and 3-methylindole in samples of plasma and rumen fluid from four cows with fog fever together with four control animals and from two cattle given L-tryptophan orally. Satisfactory recoveries of the metabolites were obtained in test samples examined by the gas liquid chromatography procedure and increased levels were found in rumen fluid after tryptophan administration. Absence of abnormal concentrations of the toxic metabolite 3-methylindole in samples from field cases of fog fever was not considered to rule out the metabolite as a possible cause of the disease in view of the rapid restoration of 3-methylindole to normal levels by the second day after loading with L-tryptophan.
Research in Veterinary Science 08/1977; 23(1):47-50. · 1.65 Impact Factor
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ABSTRACT: Significant induction of mixed-function-oxidase (MFO) activity was observed in the small intestines of rats within 4–6 hr of ingestion of a single meal containing a Brassica vegetable (cabbage). Intact Brussels sprouts and a fractionated methanol–water extract of Brussels sprouts induced similar degrees of MFO activity in the livers, and small and large intestines of rats. However, the residue left after extraction of the polar compounds did not induce MFO activity. Different amounts of the various naturally-occurring thioglycosides and glucosinolates were found in the intact Brussels sprouts and in the extract, but virtually none were found in the extracted residue. When glucusinolates that were found in Brussels sprouts (sinigrin, progoitrin, glucobrassicin and glucotropaeolin) were fed separately to rats, only the indole glucosinolate, glucobrassicin, induced MFO activity (causing induction in the small intestines of the rats). This is consistent with the inducing activity of the various hydrolysis products of this glucosinolate. This is the first study in which an attempt has been made to define the inducing compounds in Brassica vegetables by feeding the individual purified glucosinolates.
Food and Chemical Toxicology.
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ABSTRACT: Modern chemical and physico-chemical techniques have been applied to the analysis of benzyl isothiocyanate and glucosinolate in onion (Allium cepa L.) and mushroom (Agaricus bisporus). No such compounds could be detected above the limits of the analytical methods used and earlier claims for the presence of these compounds in these foods must be regarded as tentative.
Food Chemistry.
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ABSTRACT: Glucosinolates are a group of secondary products commonly, but not exclusively, found in plants of the family Cruciferae. They give rise, upon enzymic hydrolysis, to a range of volatile, pungent and physiologically active compounds. Recently, particular attention has been focused upon those that are tryptophan-derived—the indole glucosinolates (glucobrassicins). When chemically or enzymically hydrolysed these compounds give rise to a range of involatile indole compounds which have been implicated in the anti-carcinogenic and mixed-function-oxidase stimulatory activities of brassica vegetables. This review details the chemical and physiological properties of indole glucosinolates and their products and suggests possible areas for future research.
Food and Chemical Toxicology.
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ABSTRACT: Both white and Savoy-type cabbage added to a semi-purified diet at 25% dry weight and fed to rats ad lib. for 5 days significantly induced ethoxyresorufin (ERR) deethylation in the small and large intestine. Savoy cabbage also induced hepatic activity and, in general, exhibited a greater inducing effect than white cabbage. These enzyme-inducing effects were altered when the cabbage had been processed. The content of intact glucosinolate was greater in Savoy than in white cabbage. The indole glucosinolate (glucobrassicin) content of both types of cabbage was approximately halved by cooking but was unaffected by fermentation, whilst homogenization of Savoy cabbage led to the total disappearance of intact glucosinolates. Levels of the indole glucosinolate breakdown products ascorbigen and indole-3-carbinol were highest in homogenized cabbage, and ascorbigen levels were also higher in cooked than in fresh cabbage of either type. When added to the semi-purified diet and fed ad lib. to rats for 5 days, indole-3-carbinol was a potent inducer of hepatic ERR deethylation and cytochrome P-450 activity, but had much less effect in the intestine. Other glucobrassicin metabolites, diindolylmethane and indole-3-acetonitrile, also had some inducing effect in the liver but no effect in the intestine, while ascorbigen significantly induced ERR deethylation in the small and large intestine but had no effect on hepatic MFO activity.
Food and Chemical Toxicology.
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ABSTRACT: Almost one hundred glucosinolates are distributed in plants, primarily amongst members of the Cruciferae. Their presence in the genus Brassica is of major concern in any consideration of their effect in animal feedingstuffs and human foods. Following a discussion of the structure of glucosinolates and the nature of the various products formed on their enzymically induced hydrolysis, the factors affecting the qualitative and quantitative content of glucosinolates and hydrolysis products in plants, foods and feedingstuffs are considered. The major physiologically active compounds derived from glucosinolates are isothiocyanates, nitriles and oxazolidine-2-thiones and their major effects are described, particular consideration being given to the goitrogenic and anti-carcinogenic activities of some of these products. The need for detailed examinations of the chronic and subchronic effects of glucosinolates and their products, of the effect of processing on the content of these compounds and of their fate in humans, animals and poultry is also emphasised.
Food Chemistry.
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ABSTRACT: Under controlled conditions, the range of responses in Brassica napusssp. oleiferaand its two putative parents, B. rapa and B. oleracea, were tested by inoculating leaves with a mixture of eight isolates or two separate isolates of Leptosphaeria maculons. Infection resulted in a hypersensitive reaction, or localized lesions of various sizes, or systemic colonization of the lamina and petiole. Although not apparently associated with hypersensitive resistance, levels of alkenyl glucosinolates in leaves were inversely correlated with lesion extension. The value and limitations of these various sources of resistance in breeding lines of B. napus ssp. oleifera are discussed.
Transactions of the British Mycological Society.
