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The present study focuses on the utilization of moringa sprout powder (MSP) for development of healthy and ready-to-eat snack bars. Different MSP proportions (9–26%) were evaluated for snack bar formulation and compared with control formulation (0% MSP). 18% MSP-containing prototype (18MSP) was selected as the optimal formulation based on the results of the fracturability assay. 18MSP bar exhibited higher protein, ash and fat and lower total carbohydrate contents than control, and was a good source of B1 and B2 vitamins (983.0 and 94.1 μg/100 g dry matter, dm, respectively) and minerals. 18% MSP inclusion significantly (p ≤ 0.05) enhanced the contents of total amino acid (80.8 mg/g dm), the relative content of unsaturated fatty acids (FA) (64.0 g/100 g of total FA), γ-aminobutyric acid (GABA, 43.3 mg/100 g dm), and total and individual glucosinolates (GLS) (29.6, 1.1, 0.21 and 30.9 μmol/g dm for glucomoringin, glucosinalbin, glucotropaeolin and total GLS, respectively), as well as the antioxidant activity (647.2 mg TE/100 g dm). 18MSP had good sensorial acceptability, mainly due to its appearance, texture and odour. Questionnaires performed to potential Ecuadorian consumers indicated the favourable intention of purchasing the novel MSP-supplemented snack bar., This study was funded by grants AGL2015-67598-R (MINECO/FEDER), AGL2017-83718-R (AEI/FEDER, UE), and intramural project grant number PI201870I097 (CSIC).

Here we describe the structure elucidation and quantification of six glucosinolates (GSLs) from the roots of the desert plant Ochradenus baccatus, Delile 1813 (family Resedaceae; order Brassicales). The structure elucidation was established on the corresponding enzymatically desulfated derivatives of the native GSLs of the plant. Among these GSLs we describe the previously undescribed 2″-O-(α-L-arabinopyranosyloxy)benzylglucosinolate (1a), for which we propose the name glucoochradenin. The other five glucosinolates (2a-6a) were (2S)-2-hydroxy-2-phenylethylglucosinolate (2a; glucobarbarin), 2″-O-(α-L-rhamnopyranosyloxy)benzylglucosinolate (3a), benzylglucosinolate (4a; glucotropaeolin), indol-3-ylmethylglucosinolate (5a; glucobrassicin) and phenethylglucosinolate (6a; gluconasturtiin), all elucidated as their desulfo-derivatives, 2b-6b respectively). Structures were elucidated by MS and 1D and 2D-NMR techniques, the identity of the arabinose verified by ion chromatography, and the absolute configuration of the sugar units determined by hydrolysis, coupling to cysteine methyl-ester and phenyl isothiocyanate followed by HPLC-MS analysis of the resulted diastereomers. Response factors were generated for desulfo-2″-O-(α-L-arabinopyranosyloxy)benzylglucosinolate and for desulfo-2″-O-(α-L-rhamnopyranosyloxy)benzylglucosinolate and all six GSLs were quantified, indicating that the root of O. baccatus is rich in GSLs (Avg. 61.3 ± 10.0 μmol/g DW and up to 337.2 μmol/g DW).

The demand and sales of dietary supplements derived from maca (Lepidium meyenii) have skyrocketed in the last decade and a variety of related nutritional and healthcare products have mushroomed into a business with market prominence. However, the lack of standard testing protocols for quality control could jeopardize the immediate benefits of these products for public health. We describe herein the development of analytical procedures for the determination of glucosinolates (GLs), the biologically active ingredients in maca. Because of the high polarity and instability caused by enzymatic hydrolysis, GLs in maca have been exclusively analyzed using desulfated GLs. This indirect analysis requires additional sample preparation steps, which is labor-intensive, and may lose the original GLs and introduce artificial compounds. Furthermore, the reported GL profiles of maca are inconsistent and incomplete, some GLs may be structurally misidentified. In this context, we focused on direct analysis of intact GLs in maca without the enzymatic desulfation. Four GLs (sinalbin, glucolepigramin, glucolimnanthin, and glucotropaeolin) were identified as the major GLs in maca root powder. An HPLC method based on ion pair chromatography was developed to determine individual and total GLs; chromatographic separations were achieved on a Luna column (C18, 4.6 × 100 mm,3 mm) using 0.1 % TFA in water and in methanol as mobile phase in a gradient elution mode. The developed procedures were validated within the calibration range of 10–500 μg/mL. Inter- and intra-day precision were shown to be lower than 3% at all concentrations levels with recovery between 100.2 % and 103.3 %. The procedures were applied to a total of 42 maca root powder products from 11 manufacturers. Sample analysis revealed a consistent correlation of glucotropaeolin: glucolimnanthin (1: 0.19) across all products with a correlation coefficient of 0.994. The correlation in combination with total GL contents for each product could be used for authentication and GL content determination. Incorporation of the developed procedures into USP monographs will strengthen the public standards for maca powder dietary supplements.

We aimed to characterize and quantify glucosinolate compounds and contents in broccoli, and a total of 80 genotypes and eight developmental organs were analyzed with UHPLC-Triple-TOF-MS. The method was validated in terms of performance, and the coefficients of determination (R2) were 0.97 and 0.99 for glucoraphanin and gluconapin, respectively. In 80 genotypes, twelve glucosinolates were found in broccoli florets ranging from 0.467 to 57.156 µmol/g DW, with the highest glucosinolate content being approximately 122-fold higher than the lowest value. The principal component of glucobrassicin, neoglucobrassicin and glucoraphanin explained 60.53% of the total variance. There were positive correlations among hydroxyglucobrassicin, methoxyglucobrassicin, glucobrassicin, glucoerucin, gluconasturtiin, glucoraphanin, and glucotropaeolin (P

A new method was developed to determine twelve intact-glucosinolates (GLSs) (glucoiberin, GIB; glucoraphanin, GRA; glucoerucin GER; gluconapin, GNA; glucotropaeolin, GTL; glucobrassicin, GBC; gluconasturtiin, NAS; glucoalyssin, ALY; 4-hydroxyglucobrassicin, 4OH; 4-methoxyglucobrassicin, 4ME; neoglucobrassicin, NEO; sinigrin, SIN) in bee pollen, by means of liquid chromatography tandem mass spectrometry (LC-MS/MS) with electrospray ionization (ESI). An efficient extraction procedure was proposed (average analyte recoveries were between 85% and 96%); this involved a solid-liquid extraction (SLE) with heated water, followed by a solid phase extraction (SPE) with a weak anion exchange (NH2) sorbent. Chromatography was performed on a Gemini(®) C18 analytical column with a mobile phase of formic acid in water (0.5%,v/v) and formic acid in acetonitrile (0.5%,v/v), in gradient elution mode at 1mL/min, resulted in baseline-separated peaks and a run time of 30min. The method was fully validated in terms of selectivity, limits of detection (LOD) and quantification (LOQ), linearity, carry-over effect, reinjection reproducibility, precision and accuracy. A good selectivity, low LODs and LOQs, ranging from 1 to 16μg/kg, wide linear ranges from LOQ to 1000μg/kg, and satisfactory reinjection reproducibility, precision and accuracy with relative standard deviation and relative error values lower than or equal to 9%; meanwhile, results indicates a negligible carry-over effect. The proposed method was applied to analyze intact-GLSs in bee pollen. Nine of the GLSs studied were identified in certain samples analyzed over a wide concentration range (LOQ-2226μg/kg), and significant differences in GLS content were observed among the samples.

The glucosinolate (GSL) content is an important quality parameter of crops, such as mustard, horseradish or nasturtium, which are grown for their taste as condiments or for medical purposes. Accordingly, an enhancement of the GSL content should promote the large-scale cultivation of these plants. It is well known that GSLs reveal a high significance in plant defense, and that several stress factors cause an increase in the GSL concentration. The goal of the present study was to evaluate the means to stimulate the GSL biosynthesis during plant growth by applying moderate stress. The impact of different treatments on the GSL content and on growth of Tropaeolum majus L. was investigated in a greenhouse trial. Moderate stress was induced by drought, by the addition of salt, or the application of growth regulators (methyl jasmonate, salicylic acid). Moreover, cell wall lysate was applied to the plants to mimic biotic stress, such as pathogen attack. Evapotranspiration (ETP), biomass development, specific leaf weight (SLW), plant pigments, and thiol contents had been recorded to evaluate physiological changes in response to the treatments. The glucotropaeolin (GT) content, representing the sole GSL of T. majus was measured as target compound. Drought and MeJA application increased the GT concentration on dry weight basis and impacted on ETP, dry matter content, SLW and plant pigments, too. Application of salt, SA and cell wall lysate did not affect the GT concentration in a consistent way. Moderate drought and the application of MeJA are suitable tools to increase the GT concentration in T. majus . However, in case of drought the higher GT concentration was only reached at the expense of biomass production. High GT concentrations together with reasonable yields were only achieved by MeJA application.

Myrosinase (EC 3.2.3.1) found in Brassicaceae plants, is the enzyme responsible for hydrolysis of glucosinolates. As a result a variety of biologically active metabolites are liberated, whose importance in crop protection and especially in cancer chemoprevention is rapidly gaining recognition. The growing practical application of glucosinolate degradation products requires that sensitive and reliable methods of myrosinase activity determination in different types of plant samples are established. With the use of commercial myrosinase prep, we systematically optimised conditions of measurement of this enzyme activity by spectrophotometric and pH-stat methods. The parameters evaluated included: sample preparation, choice of substrate, its concentration, reaction temperature and detection wavelength. Two substrates with different spectral properties were chosen: sinigrin (SIN) and glucotropaeolin (GTL). For both substrates, the best reliability was achieved at reaction temperature of 37 °C and substrate concentration of 0.2 mM and 5 mM for spectrophotometric and pH-stat methods, respectively. GTL exhibiting higher absorption at the recommended detection wavelength of 230 nm ensured greater sensitivity of spectrophotometric determination of myrosinase activity in the case of transparent plant samples. GTL seemed to increase also the sensitivity of pH-stat method, however, in this case homogenisation of plant samples turned out to be most important. The optimised conditions were then verified for a range of plant samples. Based on these results, the optimised protocols of myrosinase activity determination for both methods are proposed.

Maca is a highly appreciated Andean crop with multiple attributed health claims due to its assortment of bioactive compounds. The extraction parameters of glucosinolates (GLs), total phenolic compounds (TPC) and antioxidant capacity (AC) of maca (Lepidium meyenii) hypocotyls were optimized using response surface methodology (RSM). The effect of different extraction parameters: temperature (°C), liquid-to-solid ratio (ml/g), time (min) and ethanol concentration (%) on GLs, TPC and AC extraction yields were investigated using a Box–Behnken design (BBD) based on response surface methodology (RSM). Maximum yields of 16.4 μmol/g of dried matter (DM), 9.89 mg of gallic acid equivalents (GAE)/g of DM and 61.4 μmol of trolox equivalents (TE)/g were obtained at conditions of 47, 70 and 70 °C, liquid-to-solid ratio of 10, 16 and 10 ml/g, extraction time of 90, 30 and 48 min and ethanol concentration of 60%, 60% and 50%, for GLs, TPC and AC respectively. Optimal extraction conditions for the simultaneous extraction of GLs, TPC and AC determined by RSM were 70 °C, 10 ml/g, 90 min and 58% ethanol with extraction yields of 14.2 μmol/g of DM, 9.3 mg of GAE/g of DM and 56.9 μmol TE/g for GLs, TPC and AC respectively. Under these conditions, glucotropaeolin represented 79% of total GLs and catechins and gallocatechin derivatives represented 97% of total phenolics. The optimized conditions could be successfully employed by the Nutraceutical industry to extract bioactive compounds from maca flour.

Glucosinolates are a group of sulphur-containing glycosides found in the plant order Brassicales which includes the Brassica vegetables such as broccoli, cabbage and cauliflower. When brought into contact with the plant enzymes, myrosinases, the glucosinolates break down releasing glucose and other products which serve principally in plant defence against herbivores. The most important of the products from a human nutritional viewpoint, are the isothiocyanates. These potent inducers of detoxifying enzymes bestow the distinct anti-cancer properties on these plants. Unique among tropical fruits, papaya is known to contain an abundance of one particular glucosinolate, glucotropaeolin. Other compounds that play a pivotal role in the chemical defence system of many plants are the cyanogenic glycosides. Cyanogenic glycosides are activated by plant enzymes in the event of pest attack, releasing the deterrent: toxic hydrogen cyanide. Papaya, in addition to glucosinolates, also contains low levels of cyanogenic glycosides, an unusual occurrence because it was assumed that the two classes of metabolites were mutually exclusive. Studies measuring the levels of both in the edible parts of the papaya fruit and other utilised tissues are discussed and considered in the context of potential human health ramifications.

Plant samples of Hornungia petraea were analyzed for glucosinolate (GLS) autolysis metabolites for the first time. GC–MS analysis of the autolysate and the synthesis of a series (12 compounds) of possible glucosinolate breakdown products revealed/corroborated the presence of glucoaubrietin, glucolimnanthin, glucolepigramin and glucotropaeolin in this species as the most likely “mustard oil” precursors. GLS degradation products identified in the autolysate of H. petraea, benzyl isothiocyanate, 3- and 4-methoxybenzyl isothiocyanate, along with several other structurally related compounds were evaluated for antimicrobial activity in order to possibly pinpoint the role of the latter secondary metabolites in the plant tissues. The assays showed a very high antibacterial activity of the tested isothiocyanates against Sarcina lutea and an antifungal effect against Aspergillus fumigatus and Candida albicans with MIC values in the order of 1 μg/ml value.

International audience; Glucosinolates (GSLs) are a class of phytochemicals found in all calciferous plants (Brassicaceae) family as well as in the whole order of Brassicales (syn. Capparales). GSLs and their hydrolysis products (e.g. isothiocyanates) are known to play a defensive role by protecting the plant against exterior aggressions and may be potent antitumor, anticancer, antioxidant and antibiotic agents. In order to obtain pure GSLs standards for developing research, an efficient two-step method was developed to preparatively isolate and separate GSLs from papaya (Carica papaya), upland cress (Barbarea verna), cauliflower (Brassica oleracea L. var. botrytis L.), and broccoletti seeds (Brassica rapa ruvo). In this process, solvent extraction was followed by a strong anion-exchange centrifugal partition chromatography protocol. TLC, HPLC-PDA, ESI-MS and NMR analysis of the collected fractions, demonstrated that the GSLs from papaya and upland cress seeds (i.e. glucotropaeolin and gluconasturtiin, respectively) as well as all the GSLs from cauliflower and broccoletti seeds (i.e. sinigrin, glucoiberin, glucoiberverin, gluconapin, glucobrassicanapin and gluconasturtiin) can be purified in a single chromatographic step. Gram amounts of pure reference standards were obtained. These results will facilitate investigation of the biological activities and the isolation of such compounds in other crucifers. (C) 2011 Published by Elsevier B.V.

Glucosinolates are sulphur-containing glycosides found in brassicaceous plants that can be hydrolysed enzymatically by plant myrosinase or non-enzymatically to form primarily isothiocyanates and/or simple nitriles. From a human health perspective, isothiocyanates are quite important because they are major inducers of carcinogen-detoxifying enzymes. Two of the most potent inducers are benzyl isothiocyanate (BITC) present in garden cress (Lepidium sativum), and phenylethyl isothiocyanate (PEITC) present in watercress (Nasturtium officinale). Previous studies on these salad crops have indicated that significant amounts of simple nitriles are produced at the expense of the isothiocyanates. These studies also suggested that nitrile formation may occur by different pathways: (1) under the control of specifier protein in garden cress and (2) by an unspecified, non-enzymatic path in watercress. In an effort to understand more about the mechanisms involved in simple nitrile formation in these species, we analysed their seeds for specifier protein and myrosinase activities, endogenous iron content and glucosinolate degradation products after addition of different iron species, specific chelators and various heat treatments. We confirmed that simple nitrile formation was predominantly under specifier protein control (thiocyanate-forming protein) in garden cress seeds. Limited thermal degradation of the major glucosinolate, glucotropaeolin (benzyl glucosinolate), occurred when seed material was heated to >120 degrees C. In the watercress seeds, however, we show for the first time that gluconasturtiin (phenylethyl glucosinolate) undergoes a non-enzymatic, iron-dependent degradation to a simple nitrile. On heating the seeds to 120 degrees C or greater, thermal degradation of this heat-labile glucosinolate increased simple nitrile levels many fold.

Glucotropaeolin and total phenolic concentrations were assessed in three different organs (inflorescences, leaves, unripe seeds) of nasturtium ( Tropaeolum majus L.), which are consumed as herbal plant products, in order to determine the effect of short-term and moderate UV-B exposure as targeted postharvest stress treatment on the secondary plant metabolism. For this purpose, nasturtium plants were subjected to two UV-B radiation levels: 0.075 and 0.15 W h m − 2 . The results clearly demonstrate that the plant response to short-term and moderate UV-B exposure is organ-, plant tissue age-, and phytochemical-specific and that these factors influence a change of secondary metabolism as revealed by the different phytochemical concentration levels elicited. Industrial relevance In food processing UV treatment is mainly attributed to disinfection. This study examined the feasibility of short-term and moderate UV-B application as emerging technology for enhancing health-promoting phytochemicals in freshly consumed plant products (inflorescences, leaves, unripe seeds) demonstrated by the herbal plant nasturtium. Optimizing phytochemical concentration by targeted postharvest UV-B applications will add health value and subsequently generate new opportunities for growers and processors by achieving the health-oriented food market.

The main goal of this study was to determine the effect of a freeze-dried aqueous extract of the red variety of Lepidium meyenii (Red Maca) on testosterone-induced benign prostatic hyperplasia (BPH) in adult rats of the Holtzman strain. Rats were treated with freeze-dried aqueous extract of Red Maca at doses of 0, 0.01, 0.05, 0.1, and 0.5 g/kg body wt. A positive control group received Finasteride (0.6 mg/kg body wt.). After treatment, the animals were sacrificed, and the ventral prostate was extracted, and weighed. HPLC was used to determine the presence of glucosinolates in Red Maca. The prostate weight diminished in a dose-dependent fashion in rats treated with Red Maca. The effect of Red Maca was better than that observed with Finasteride. Finasteride, but not Red Maca, reduced seminal vesicles weight. Analysis of the HPLC indicated the presence of benzyl glucosinolate (Glucotropaeolin) with a content of 0.639%. Serum testosterone levels were not affected by Red Maca. Moreover, serum testosterone levels were not related to prostate or seminal vesicles weight in rats treated with vehicle and Red Maca. In conclusion, Red Maca administered orally in rats seems to exert an inhibitory effect at a level post DHT conversion, on the BPH-induced experimentally, although a direct measure of reductase action would still be required.

Levels of glucosinolates in Farsetia aegyptia var. ovalis suspension cultures were monitored after treatment with yeast extract, chitosan, methyl jasmonate, ampicillin, and Phytophthora infestans autoclaved mycelia as elicitors. Glucosinolates were identified, and an estimation of their levels obtained from their hydrolysis products. Yeast extract improved glucotropaeolin (benzyl-glucosinolate) and glucocheirolin [3-(methylsulfonyl)propyl-glucosinolate] accumulation, and production of sec-butyl, isobutylglucosinolate and gluconasturtiin (2-phenylethyl-glucosinolate) was only detected in yeast elicited cultures. Increases were shown in glucotropaeolin levels in cultures elicited using methyljasmonate, and chitosan and methyljasmonate in combination.

Two root-colonizing Fusarium strains, Ls-F-in-4-1 and Rs-F-in-11, isolated from roots of Brassicaceae plants, induced the resistance in Lepidium sativum seedlings against Pythium ultimum. These strains caused an increase in the content of benzyl isothiocyanate, and of its precursor glucotropaeolin, in the roots of the host plants. The increased isothiocyanate content is one of the factors contributing to the resistance of L. sativum against P. ultimum. To be transformed into the fungitoxic compound benzyl isothiocyanate, glucotropaeolin has to be hydrolyzed by myrosinase, which can be produced either by plants or microorganisms. The Fusarium strain Ls-F-in-4-1 has a myrosinase activity but the strain Rs-F-in-11 has not. These results suggest that both strains are able to trigger the metabolic pathway leading to benzyl isothiocyanate production in the plant. In the case of the myrosinase-negative strain Rs-F-in-11, hydrolyzation into isothiocyanate is only due to the myrosinase activity of the plant, and in the other case, the myrosinase produced by the strain Ls-F-in-11 also would contribute to the production of isothiocyanate. This paper reports a new mode of action of non-pathogenic Fusarium strains in controlling P. ultimum.

Maca (Lepidium meyenii Walp) is a food plant belonging to the Cruciferae family. It is very interesting because it has one of the highest frost tolerances of any cultivated plant and can be grown at high altitudes (3800–4800 m) (Bonnier, 1986). Maca dry tubers were bought from INIA (Instituto National de Investigation Agroindustrial de Huancayo, Peru); a sample has been deposited in the Herbarium Neapolitanum the Dipartimento di Biologia Vegetale Universita degli Studi ‘Federico II’ of Naples (herbarium code NAP).

The aim of this study was to optimize by micellar electrokinetic chromatography the separation of four glucosinolates, i.e. sinigrin, glucobrassicin and methoxyglucobrassicin involved in Cruciferae resistance mechanisms and glucotropaeolin used as an internal standard. The separation borate buffer which contained sodium dodecyl sulphate, tetramethylammonium hydroxide and methanol was firstly optimized by using a three variable Doehlert experimental design. The optimum concentrations found enabled, for the first time, to obtain an acceptable resolution between the two indole glucosinolates, glucobrassicin and methoxyglucobrassicin. Modifications of the method such as a capillary pre-rinse with pure borate buffer and a step change in voltage during experiment were performed to improve the resolutions between glucosinolates and to reduce the analysis time. This method was validated by a statistical analysis and showed good linearity, repeatability and reproducibility.

A commercial crude sulfatase from snail (Helix pomatia) was purified by ion exchange, affinity and FPLC gel-filtration chromatography. The enzyme isolated, which was ca. 37-fold more active than the commercial one, was covalently immobilized on nylon 6.6 by the cross linking method. Immobilized sulfatase was used to produce some desulfo-glucosinolates (DSGLs) on the gram-scale, starting from glucotropaeolin, glucoraphenin and epi-progoitrin, and for HPLC analyses of glucosinolates (GLs) contained in cruciferous material and rapeseed in particular. The immobilized enzyme, as well as allowing the standardization of the HPLC method for GLs analysis, seems to be an efficient system for producing DSGLs which are interesting starting materials to prepare bio-active structures through further chemical modifications.

The syntheses of 3,4,6- tri -O- acetyl-2-deoxy-1-thio- d -arabino- hexopyranose , 2,4,6- tri -O- acetyl-3-deoxy-1-thio-β- d -ribo- hexopyranose , 2,3,6- tri -O- benzoyl-4-deoxy-1-thio-β- d -xylo- hexopyranose , and 2,3,4- tri -O- acetyl-6-deoxy-1-thio-β- d -glucopyranose are reported. These thiols were coupled with phenylacetohydroximoyl chloride or indol-3-ylacetohydroximoyl chloride, respectively. Sulfation and subsequent deprotection yielded the corresponding deoxy derivatives of glucotropaeolin and glucobrassicin, two major representatives of the glucosinolate family.

Starting from tetra- O -benzyl- d -glucose ( 2 ), the first synthesis of a C -analogue 7 of glucotropaeolin, the major glucosinolate of the genus Nasturtium was performed. Compound 7 constitutes a potential non-hydrolyzable inhibitor of the enzyme myrosinase.

Larvae of the sawfly Athalia rosae sequester glucosinolates from their various host plants of the Brassicaceae into their hemolymph for defensive purposes. We found that the glucosinolate concentration in the insect varies in a fluctuating manner during larval development. Analyses of larvae which had been offered diets with different glucosinolate profiles showed that there is an equilibrium between a rapid uptake of glucosinolates into the hemolymph and a continuous turn-over. Injection of glucotropaeolin into the hemolymph and ingestion of the same amount resulted in similar levels of intact glucosinolates recovered from larvae after different periods of time. This indicates that hemolymph glucosinolates are the principal source for glucosinolate degradation. Feeding experiments with [14C]-labeled glucotropaeolin revealed that the majority of the ingested glucosinolate is excreted as one or more unidentified metabolite(s) within 14 h. We found no indication for the presence of an insect myrosinase, or sulfatase in A. rosae, which have been shown to be involved in glucosinolate metabolism in other specialists feeding on Brassicaceae. Furthermore, the metabolism of sinalbin in A. rosae seems to result in different products than its metabolism in the caterpillar Pieris rapae. Obviously, A. rosae has yet another way of coping with the glucosinolates.

A 5a-carba-analogue 4 of glucotropaeolin 2 was synthesized in racemic form and showed a good inhibiting power against myrosinase.

A synthetic sequence was devised to produce phospho-glucotropaeolin 6 , the first representative of phosphate bio-isosteres of naturally-occurring glucosinolates with a view to enzymatic studies.

Determination of the amount of benzyl glucosinolate (glucotropaeolin) in black pepper seed and products affords a sensitive method of determining the degree of adulteration with papaya seed. The glucotropaeolin may be estimated directly using gas chromatography, or indirectly by measuring the glucose which is quantitatively released following enzymic treatment. No attempt has been made to optimise the conditions of the extraction since, as described, the method allows detection of 0·1% papaya seed contamination/adulteration.

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.

The incorporation of DL - N -hydroxyphenylalanine-2- 14 C into the mustard oil glucoside glucotropaeolin was demonstrated by plant feeding experiments. The efficiency of conversion of 14 C from this acid into the aglycone moiety of glucotropaeolin was higher than that from DL -phenylalanine-2- 14 C or -3- 14 C, and was comparable with that observed previously from phenylacetaldehyde oxime-1- 14 C. These results support the reaction sequence: phenylalanine → N -hydroxyphcnylalanine → phenylacetaldehyde oxime → glucotropaeolin. Enzyme preparations were obtained from Sinapis alba L., Tropoeolum majus L. and Nasturtium officinale R.Br. which catalyze the transformation of N -hydroxyphenylalanine to phenylacetaldehyde oxime. Although no absolute requirement for cofactors could be found, an increase in the rate of formation of the aldehyde oxime and consumption of oxygen was observed using FMN and enzyme preparations from T . majus and S . alba . Using the enzyme from T . majus it was demonstrated that the μmoles of phenylacetaldehyde oxime formed and of oxygen consumed were equivalent. In this case FMN appeared to be the prosthetic group and oxygen the physiological hydrogen acceptor. In addition to this enzymatic conversion, an unspecific and nonenzymatic oxidation of the N -hydroxyamino acid to phenylacetaldehyde oxime and phenylacetonitrile was observed.

A β-thioglucosidase capable of hydrolyzing mustard oil glucosides is of rare occurrence in fungi. Aspergillus sydowi QM 31c is a good source of the enzyme. The fungal enzyme resembles mustard seed myrosinase. Both enzymes degrade sinigrin producing glucose, KHSO4, and allyl isothiocyanate. They attack only the mustard oil thioglucosides, and are inactive on thioglucosides not having this configuration. The fungal enzyme is relatively more active on sinalbin and glucotropaeolin than is myrosinase. The fungal enzyme is less resistant to heat, acids, alkalies, and chemical inhibitors than is the mustard enzyme.