High throughput screening of mutants of oat that are defective in triterpene synthesis.

The triterpenes are a large and diverse group of plant natural products that have important functions in plant protection and food quality, and a range of pharmaceutical and other applications. Like sterols, they are synthesised from mevalonate via the isoprenoid pathway, the two pathways diverging after 2,3-oxidosqualene. During triterpene synthesis 2,3-oxidosqualene is cyclised to one of a number of potential products, the most common of these being the pentacyclic triterpene beta-amyrin.

L-alpha-glycerophosphocholine contributes to meat's enhancement of nonheme iron absorption.

In this research, our aim was to isolate and characterize the substance known as "meat factor," which is reported to enhance nonheme iron absorption. We used various analytical techniques, and the final step was a human study to measure the effect of a candidate compound on iron absorption. Lean beef was selected for study, as it is known to increase nonheme iron absorption.

Metabolic footprinting as a tool for discriminating between brewing yeasts.

The characterization of industrial yeast strains by examining their metabolic footprints (exometabolomes) was investigated and compared to genome-based discriminatory methods. A group of nine industrial brewing yeasts was studied by comparing their metabolic footprints, genetic fingerprints and comparative genomic hybridization profiles. Metabolic footprinting was carried out by both direct injection mass spectrometry (DIMS) and gas chromatography time-of-flight mass spectrometry (GC-TOF-MS), with data analysed by principal components analysis (PCA) and canonical variates analysis (CVA).

Identification and quantification of glucosinolates in sprouts derived from seeds of wild Eruca sativa L. (salad rocket) and Diplotaxis tenuifolia L. (wild rocket) from diverse geographical locations.

The Brassicaceae rocket species Eruca sativa L. (salad rocket) and Diplotaxis tenuifolia L. (wild rocket) are consumed throughout the world in salads, predominantly the leaves but also the flowers and more recently the sprouts (seedlings).

Shall I compare thee to a GM potato?

A fundamental issue in the safety assessment of genetically modified crops is the question of whether unintentional changes have occurred in the crop plant as a consequence of the genetic modification. This question was addressed recently by using a powerful metabolite fingerprinting and metabolite profiling method to assess whether genetically modified potatoes are substantially similar to their corresponding conventional cultivars.

Ontogenic profiling of glucosinolates, flavonoids, and other secondary metabolites in Eruca sativa (salad rocket), Diplotaxis erucoides (wall rocket), Diplotaxis tenuifolia (wild rocket), and Bunias orientalis (Turkish rocket).

As an influence of the Mediterranean diet, rocket species such as Eruca sativa L., Diplotaxis species, and Bunias orientalis L. are eaten all over the world at different ontogenic stages in salads and soups.

Dihydrocaffeoyl polyamines (kukoamine and allies) in potato (Solanum tuberosum) tubers detected during metabolite profiling.

Four related phenolic amides previously undescribed from the species were revealed during metabolic profiling of potato (Solanum tuberosum) tubers. N(1),N(12)-Bis(dihydrocaffeoyl)spermine (kukoamine A) and N(1),N(8)-bis(dihydrocaffeoyl)spermidine were positively identified by comparison with authentic standards, while the structures N(1),N(4),N(12)-tris(dihydrocaffeoyl)spermine and N(1),N(4),N(8)-tris(dihydrocaffeoyl)spermidine are proposed for the other two metabolites. Each amide was present at several tens of micrograms per gram of dry matter.

Stability of the major allergen Brazil nut 2S albumin (Ber e 1) to physiologically relevant in vitro gastrointestinal digestion.

The major 2S albumin allergen from Brazil nuts, Ber e 1, was subjected to gastrointestinal digestion using a physiologically relevant in vitro model system either before or after heating (100 degrees C for 20 min). Whilst the albumin was cleaved into peptides, these were held together in a much larger structure even when digested by using a simulated phase 1 (gastric) followed by a phase 2 (duodenal) digestion system. Neither prior heating of Ber e 1 nor the presence of the physiological surfactant phosphatidylcholine affected the pattern of proteolysis.

Isolation, identification and stability of acylated derivatives of apigenin 7-O-glucoside from chamomile (Chamomilla recutita [L.] Rauschert).

The major flavonoids in the white florets of chamomile (Chamomilla recutita [L.] Rauschert) were rapidly purified using a combination of polyamide solid-phase extraction and preparative HPLC. From the combined LC/MS, LC/MS/MS, and NMR data the apigenin glucosides were identified as apigenin 7-O-glucoside (Ap-7-Glc), Ap-7-(6"-malonyl-Glc), Ap-7-(6"-acetyl-Glc), Ap-7-(6"-caffeoyl-Glc), Ap-7-(4"-acetyl-Glc), Ap-7-(4"-acetyl,6"-malonyl-Glc), and a partially characterised apigenin-7-(mono-acetyl/mono-malonylglucoside) isomer.

Profiling glucosinolates, flavonoids, alkaloids, and other secondary metabolites in tissues of Azima tetracantha L. (Salvadoraceae).

Azima tetracantha L. (needle bush; bee sting bush; Salvadoraceae) is used as a food and for various herbal medicines in Africa, India, and Madagascar, but there is very little information on the secondary metabolites in this species. High concentrations of N-methoxy-3-indolylmethyl-glucosinolate, a common glucosinolate of Brassica crops such as Brussels sprouts and broccoli, were found in the roots and seeds of A.

Mass spectrometry and structural characterization of 2S albumin isoforms from Brazil nuts (Bertholletia excelsa).

Proteomic approaches have been used to characterise the main 2S albumin isoforms from Brazil nuts (Bertholletia excelsa). Whilst most isoforms ( approximately 10 discrete protein species) exhibited molecular masses of around 12 kDa with a high amino acid sequence homology, important charge heterogeneity was found, with pIs varying between 4.6 and 6.

Screening crucifer seeds as sources of specific intact glucosinolates using ion-pair high-performance liquid chromatography negative ion electrospray mass spectrometry.

Seeds, of either commercial crucifer crops or some wild and weed relatives, were screened for intact glucosinolates using a previously developed ion-pair LC-MS method. This method, in contrast to GC-MS techniques, ensures the accurate measurement of all classes of glucosinolates. Many crucifer seeds contained very high concentrations of glucosinolates with low concentrations of additional pigments and secondary metabolites.

Characterization of metabolites of hydroxycinnamates in the in vitro model of human small intestinal epithelium caco-2 cells.

Hydroxycinnamic acids are antioxidant phenolic compounds which are widespread in plant foods, contribute significantly to total polyphenol intakes, and are absorbed by humans. The extent of their putative health benefit in vivo depends largely on their bioavailability. However, the mechanisms of absorption and metabolism of these phenolic compounds have not been described.

Absorption of hydroxycinnamates in humans after high-bran cereal consumption.

Hydroxycinnamic acids are a group of phenolic compounds that exhibit a wide range of in vitro chemoprotective and antioxidant properties. Cereals containing a high proportion of the bran layers are rich in ester-linked hydroxycinnamic acids, such as ferulic and diferulic acids. The present work investigated the absorption in humans of hydroxycinnamic acids from high-bran breakfast cereal (wheat).

Profiling glucosinolates and phenolics in vegetative and reproductive tissues of the multi-purpose trees Moringa oleifera L. (horseradish tree) and Moringa stenopetala L.

Moringa species are important multi-purpose tropical crops, as human foods and for medicine and oil production. There has been no previous comprehensive analysis of the secondary metabolites in Moringa species. Tissues of M.

Absorption/metabolism of sulforaphane and quercetin, and regulation of phase II enzymes, in human jejunum in vivo.

For the first time the human intestinal effective permeability, estimated from the luminal disappearance and intestinal metabolism of phytochemicals, sulforaphane and quercetin-3,4'-glucoside, as well as the simultaneous changes in gene expression in vivo in enterocytes, has been studied in the human jejunum in vivo (Loc-I-Gut). Both compounds as components of an onion and broccoli extract could readily permeate the enterocytes in the perfused jejunal segment. At the physiologically relevant, dietary concentration tested, the average effective jejunal permeability (Peff) and percentage absorbed (+/- S.

Involvement of dehydroalanine and dehydrobutyrine in the addition of glutathione to nisin.

Nisin variants and fragments were reacted with glutathione, and the products of the reactions were analyzed by matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS) and liquid chromatography/mass spectrometry (LC-MS). Reactions between glutathione and either [Ala5]nisin or [Ala33]nisin resulted in products with two glutathione molecules conjugated to one nisin variant molecule. Only one glutathione molecule was added to [Ala5,Ala33]nisin.

Characterization and content of flavonoid glycosides in genetically modified tomato (Lycopersicon esculentum) fruits.

There is a growing interest in producing food plants with increased amounts of flavonoids because of their potential health benefits. Tomatoes contain small amounts of flavonoids, most of which are located in the peel of the fruit. It has been shown that flavonoid accumulation in tomato flesh, and hence an overall increase in flavonoid levels in tomato fruit, can be achieved by means of simultaneous overexpression of the maize transcription factors LC and C1.

Metabolism of quercetin-7- and quercetin-3-glucuronides by an in vitro hepatic model: the role of human beta-glucuronidase, sulfotransferase, catechol-O-methyltransferase and multi-resistant protein 2 (MRP2) in flavonoid metabolism.

Quercetin-3- and quercetin-7-glucuronides are major products of small intestine epithelial cell metabolism (J. Nutr. 130 (2000) 2765) but it is not known if quercetin glucuronides can be further processed in the liver or if they are excreted directly.

Identification of the major glucosinolate (4-mercaptobutyl glucosinolate) in leaves of Eruca sativa L. (salad rocket).

The major and structurally unique glucosinolate (GLS) in leaves of Eruca sativa L. (salad rocket) was identified as 4-mercaptobutyl GLS. Both 4-methylthiobutyl GLS and 4-methylsulfinylbutyl GLS were also present, but at lower concentrations.

Intact glucosinolate analysis in plant extracts by programmed cone voltage electrospray LC/MS: performance and comparison with LC/MS/MS methods.

We present a comprehensive, sensitive, and highly specific negative ion electrospray LC/MS method for identifying all structural classes of glucosinolates in crude plant extracts. The technique is based on the observation of simultaneous maxima in the abundances of the m/z 96 and 97 ions, generated by programmed cone voltage fragmentation, in the mass chromatogram. The abundance ratios lie in the range 1:2-1:4 ([m/z 96]/[m/z 97]).

4-Hydroxycinnamoyl-CoA hydratase/lyase, an enzyme of phenylpropanoid cleavage from Pseudomonas, causes formation of C(6)-C(1) acid and alcohol glucose conjugates when expressed in hairy roots of Datura stramonium L.

4-Hydroxycinnamoyl-CoA hydratase/lyase (HCHL), a crotonase homologue of phenylpropanoid catabolism from Pseudomonas fluorescens strain AN103, led to the formation of 4-hydroxybenzaldehyde metabolites when expressed in hairy root cultures of Datura stramonium L. established by transformation with Agrobacterium rhizogenes. The principal new compounds observed were the glucoside and glucose ester of 4-hydroxybenzoic acid, together with 4-hydroxybenzyl alcohol- O-beta- D-glucoside.

Use of an oral/intravenous dual-label stable-isotope protocol to determine folic acid bioavailability from fortified cereal grain foods in women.

Folic acid fortification, mandatory in the United States, is currently being considered by the UK. The hypothesis that the matrix of some cereal-product vehicles may result in low fortificant bioavailability was tested using a dual oral/intravenous (i.v.

Polyphenols from alcoholic apple cider are absorbed, metabolized and excreted by humans.

We determined the uptake and excretion of low doses of polyphenols in six subjects who each consumed 1.1 L of an alcoholic cider beverage. Over a 24-h period, no phloretin was detected in plasma (detection limit = 0.