Microbial terroir: associations between soil microbiomes and the flavor chemistry of mustard (Brassica juncea).

Here, we characterized the independent role of soil microbiomes (bacterial and fungal communities) in determining the flavor chemistry of harvested mustard seed (Brassica juncea). Given the known impacts of soil microbial communities on various plant characteristics, we hypothesized that differences in rhizosphere microbiomes would result in differences in seed flavor chemistry (glucosinolate content). In a glasshouse study, we introduced distinct soil microbial communities to mustard plants growing in an otherwise consistent environment. At the end of the plant life cycle, we characterized the rhizosphere and root microbiomes and harvested produced mustard seeds for chemical characterization. Specifically, we measured the concentrations of glucosinolates, secondary metabolites known to create spicy and bitter flavors. We examined associations between rhizosphere microbial taxa or genes and seed flavor chemistry. We identified links between the rhizosphere microbial community composition and the concentration of the main glucosinolate, allyl, in seeds. We further identified specific rhizosphere taxa predictive of seed allyl concentration and identified bacterial functional genes, namely genes for sulfur metabolism, which could partly explain the observed associations. Together, this work offers insight into the potential influence of the belowground microbiome on the flavor of harvested crops.

Relationship between secondary metabolites and insect loads in cabbage with different leaf shapes and positions.

INTRODUCTION: Secondary metabolites in plants play a crucial role in defense mechanisms against insects, pests, and pathogens. These metabolites exhibit varying distributions within and among plant parts under different biotic and abiotic conditions. Understanding the intricate relationships between secondary metabolites and insect populations can be helpful for elucidating plant defense mechanisms and enhancing agricultural managing efficiencies. OBJECTIVE: To investigate the influence of the glucosinolate profile in the leaves of three cabbage (Brassica oleracea var. capitata L.) varieties on insect loads. METHODS: Glucosinolate profiles across different leaf positions (such as bottom, middle, and center) and leaf shapes (such as curly and non-curly leaf) of three cabbage varieties (Xiagan [XGA], Xiaguang [XGU], and Qiangxia [QIX]) were analyzed by using high-performance liquid chromatography-mass spectrometry (LC-MS). The insect loads were recorded by visually inspecting the upper and lower layers of each target leaf. RESULTS: Increasing concentrations of four glucosinolates, namely, glucoiberin, progoitrin, glucoraphanin, and glucobrassicin, were positively related to insect loads. While increasing concentrations of the other four glucosinolates, such as neoglucobrassicin, 4-methoxyglucobrassicin, sinigrin, and gluconapin, were negatively related to insect loads. Furthermore, both glucosinolate synthesis and insect loads were significantly higher in the curly-shaped and middle-position leaves than in the non-curly-shaped and bottom- and central-position leaves across the cabbage varieties. CONCLUSION: Differences in glucosinolate profiles across leaf positions and shapes strongly influenced the insect loads of the three Brassica varieties. This link may further extend our understanding of the real defense power of a particular variety against herbivore damage.

Variations of Major Glucosinolates in Diverse Chinese Cabbage (Brassica rapa ssp. pekinensis) Germplasm as Analyzed by UPLC-ESI-MS/MS.

In this study, the variability of major glucosinolates in the leaf lamina of 134 Chinese cabbage accessions was investigated using Acquity ultra-performance liquid chromatography (UPLC-ESI-MS/MS). A total of twenty glucosinolates were profiled, of which glucobrassicanapin and gluconapin were identified as the predominant glucosinolates within the germplasm. These two glucosinolates had mean concentration levels above 1000.00 µmol/kg DW. Based on the principal component analysis, accessions IT186728, IT120044, IT221789, IT100417, IT278620, IT221754, and IT344740 were separated from the rest in the score plot. These accessions exhibited a higher content of total glucosinolates. Based on the VIP values, 13 compounds were identified as the most influential and responsible for variation in the germplasm. Sinigrin (r = 0.73), gluconapin (r = 0.78), glucobrassicanapin (r = 0.70), epiprogoitrin (r = 0.73), progoitrin (r = 0.74), and gluconasturtiin (r = 0.67) all exhibited a strong positive correlation with total glucosinolate at p < 0.001. This indicates that each of these compounds had a significant influence on the overall glucosinolate content of the various accessions. This study contributes valuable insights into the metabolic diversity of glucosinolates in Chinese cabbage, providing potential for breeding varieties tailored to consumer preferences and nutritional demands.

Cultivated Winter-Type Lunaria annua L. Seed: Deciphering the Glucosinolate Profile Integrating HPLC, LC-MS and GC-MS Analyses, and Determination of Fatty Acid Composition.

Lunaria annua L. (Brassicaceae) is an ornamental plant newly identified in Europe as a promising industrial oilseed crop for its valuable very-long-chain monounsaturated fatty acids (MUFAs), especially erucic acid (EA) and nervonic acid (NA). L. annua seeds were obtained from annual winter-type plants selected and cultivated in Northern France. Using a systematic multiple-method approach, we set out to determine the profile and content of glucosinolates (GSLs), which are the relevant chemical tag of Brassicaceae. Intact GSLs were analyzed through a well-established LC-MS method. Identification and quantification were performed by HPLC-PDA of desulfo-GSLs (dGLs) according to the official EU ISO method. Moreover, GSL structures were confirmed by GC-MS analysis of the related isothiocyanates (ITCs). Seven GSLs were identified, directly or indirectly, as follows: 1-methylethyl GSL, (1S)-1-methylpropyl GSL, (Rs)-5-(methylsulfinyl)pentyl GSL, (Rs)-6-(methylsulfinyl)hexyl GSL, (2S)-2-hydroxy-4-pentenyl GSL, 2-phenylethyl GSL, and 1-methoxyindol-3-ylmethyl GSL. In other respects, the FA composition of the seed oil was determined. Results revealed cultivated L. annua seed to be a source of NA-rich oil, and presscake as a valuable coproduct. This presscake is indeed rich in GSLs (4.3% w/w), precursors of promising bioactive molecules for agricultural and nutraceutical applications.

Comprehensive Quality Assessment of Brassica napus L. Seeds via HPTLC, LC-QToF, and Anatomical Investigation.

The Brassicaceae family, commonly referred to as cruciferous plants, is globally cultivated and consumed, with the Brassica genus being particularly renowned for its functional components. These vegetables are rich sources of nutrients and health-promoting phytochemicals, garnering increased attention in recent years. This study presents a comprehensive microscopic, chromatographic, and spectroscopic characterization of Brassica napus L. seeds from Kazakhstan aimed at elucidating their morphological features and chemical composition. Microscopic analysis revealed distinct localization of flavonoids, total lipids, and alkaloids. High-performance thin-layer chromatography (HPTLC) analysis of seed extracts demonstrated a complex chemical profile with significant quantities of non-polar compounds in the hexane extracts. Additionally, methanolic extracts revealed the presence of diverse chemical compounds, including alkaloids, flavonoids, and glucosinolates. The chemical composition exhibited varietal differences across different Brassica species, with B. napus L. seeds showing higher concentrations of bioactive compounds. Furthermore, liquid chromatography-quadrupole time-of-flight mass spectrometry (LC-QToF-MS) analysis provided insights into the chemical composition, with sinapine isomers, feruloyl, and sinapoyl choline derivatives as major compounds in the seeds. This study contributes to a better understanding of the chemical diversity and quality control methods' approximations of B. napus L. seeds, highlighting their importance in functional food and nutraceutical applications.

LC/MS-Based Metabolomics Reveals Chemical Variations of Two Broccoli Varieties in Relation to Their Anticholinesterase Activity: In vitro and In silico Studies.

Broccoli is commonly consumed as food and as medicine. However, comprehensive metabolic profiling of two broccoli varieties, Romanesco broccoli (RB) and purple broccoli (PB), in relation to their anticholinergic activity has not been fully disclosed. A total of 110 compounds were tentatively identified using UPLC-Q-TOF-MS metabolomics. Distinctively different metabolomic profiles of the two varieties were revealed by principal component analysis (PCA). Furthermore, by volcano diagram analysis, it was found that PB had a significantly higher content of phenolic acids, flavonoids, and glucosinolates, indicating the different beneficial health potentials of PB that demonstrated higher antioxidant and anticholinergic activities. Moreover, Pearson's correlation analysis revealed 18 metabolites, mainly phenolic and sulfur compounds, as the main bioactive. The binding affinity of these biomarkers to the active sites of acetyl- and butyryl-cholinesterase enzymes was further validated using molecular docking studies. Results emphasize the broccoli significance as a functional food and nutraceutical source and highlight its beneficial effects against Alzheimer's disease.

Chemical Composition, Antimicrobial and Antioxidant Activities of Broccoli, Kale, and Cauliflower Extracts.

The brassicas have the potential to prevent chronic non-communicable diseases and it is proposed to evaluate the chemical composition, antioxidant and antimicrobial potential of broccoli, cabbage and extracts. The extracts were prepared and characterized and the antioxidant potential was evaluated against three radicals while the antimicrobial potential was analyzed using three techniques against four bacteria. The extracts have glucosinolates and phenolic compounds in their composition, and effectively inhibit the 2,2-diphenyl-1-picrylhydrazyl radical. The extracts of broccoli and cauliflower showed an inhibitory effect against hydroxyl radicals and nitric oxide. Disk diffusion showed that broccoli and cauliflower extract were active against three bacteria, while kale extract showed active halos for Gram-negative bacteria. Kale extract had an inhibitory effect Gram-positive bacteria, cauliflower extract inhibited the growth of Staphylococcus aureus. The cauliflower extract thus had a higher concentration of phenols, a strong antioxidant activity and promising results at a concentration of 100 mg/mL against S. aureus.

Red and white cabbages: An updated comparative review of bioactives, extraction methods, processing practices, and health benefits.

Red and white cabbages (Brassica oleracea var. capitata f. alba and rubra, respectively) are two of the most commercially valued vegetables in crucifers, well-recognized for their unique sensory and nutritive attributes in addition to a myriad of health-promoting benefits. The current review addressed the differential qualitative/quantitative phytochemical make-ups for the first time for better utilization as nutraceuticals and to identify potential uses based on the chemical makeup of both cultivars (cvs.). In addition, extraction methods are compared highlighting their advantages and/or limitations with regards to improving yield and stability of cabbage bioactives, especially glucosinolates. Besides, the review recapitulated detailed action mechanism and safety of cabbage bioactives, as well as processing technologies to further improve their effects are posed as future perspectives. White and red cabbage cvs. revealed different GLSs profile which affected by food processing, including enzymatic hydrolysis, thermal breakdown, and leaching. In addition, the red cultivar provides high quality pigment for industrial applications. Moreover, non-conventional modern extraction techniques showed promising techniques for the recovery of their bioactive constituents compared to solvent extraction. All these findings pose white and red cabbages as potential candidates for inclusion in nutraceuticals and/or to be commercialized as functional foods prepared in different culinary forms.

Comprehensive two-dimensional gas chromatography-time of flight mass spectrometry as a tool for tracking roasting-induced changes in the volatilome of cold-pressed rapeseed oil.

The aim of this study was to track changes in the volatilome of cold-pressed oil and press cakes obtained from roasted seeds and to combine it with the profile of non-volatile metabolites in a single study, in order to understand pathways of volatile organic compound (VOC) formation caused by thermal processing. Comprehensive two-dimensional gas chromatography-time of flight mass spectrometry was used for the analysis of VOCs in cold-pressed oils and corresponding press cakes obtained after roasting of seeds at 140 and 180 °C prior to pressing. Contents of primary metabolites (amino acids, saccharides, fatty acids) as well as selected secondary metabolites (glucosinolates, polyphenols) were determined, as many of them serve as precursors to volatile compounds formed especially in thermal reactions. After roasting, the formation of Maillard reaction products increased, which corresponded to the reduction of free amino acids and monosaccharides. Moreover, levels of the products of thermal oxidation of fatty acids, such as aldehydes and ketones, increased with the increasing temperature of roasting, although no significant changes were noted for fatty acids. Among sulphur-containing compounds, contents of the products and intermediates of methionine Strecker degradation increased significantly with the increasing temperature of roasting. Degradation of glucosinolates to nitriles occurred after thermal treatment. The results of this study confirmed that seed roasting before cold pressing has a significant effect on the volatiles, but also indicated roasting-induced changes in non-volatile metabolites of oil and press cake. Such an approach helps to understand metabolic changes occurring during rapeseed processing in cold-pressed oil production.

Salt-Affected Rocket Plants as a Possible Source of Glucosinolates.

Soil salinity can have various negative consequences on agricultural products, from their quality and production to their aesthetic traits. In this work, the possibility to use salt-affected vegetables, that otherwise would be discarded, as a source of nutraceuticals was explored. To this aim, rocket plants, a vegetable featuring bioactive compounds such as glucosinolates, were exposed to increasing NaCl concentrations in hydroponics and analysed for their content in bioactive compounds. Salt levels higher than 68 mM produced rocket plants that did not comply with European Union regulations and would therefore be considered a waste product. Anyway, our findings, obtained by Liquid Chromatography-High Resolution Mass Spectrometry, demonstrated a significant increase in glucosinolates levels in such salt-affected plants. opening the opportunity for a second life of these market discarded products to be recycled as glucosinolates source. Furthermore, an optimal situation was found at NaCl 34 mM in which not only were the aesthetic traits of rocket plants not affected, but also the plants revealed a significant enrichment in glucosinolates. This can be considered an advantageous situation in which the resulting vegetables still appealed to the market and showed improved nutraceutical aspects.

Insights into glucosinolate accumulation and metabolic pathways in Isatis indigotica Fort.

BACKGROUND: Glucosinolates (GSLs) play important roles in defending against exogenous damage and regulating physiological activities in plants. However, GSL accumulation patterns and molecular regulation mechanisms are largely unknown in Isatis indigotica Fort. RESULTS: Ten GSLs were identified in I. indigotica, and the dominant GSLs were epiprogoitrin (EPI) and indole-3-methyl GSL (I3M), followed by progoitrin (PRO) and gluconapin (GNA). The total GSL content was highest (over 20 µmol/g) in reproductive organs, lowest (less than 1.0 µmol/g) in mature organs, and medium in fresh leaves (2.6 µmol/g) and stems (1.5 µmol/g). In the seed germination process, the total GSL content decreased from 27.2 µmol/g (of seeds) to 2.7 µmol/g (on the 120th day) and then increased to 4.0 µmol/g (180th day). However, the content of indole GSL increased rapidly in the first week after germination and fluctuated between 1.13 µmol/g (28th day) and 2.82 µmol/g (150th day). Under the different elicitor treatments, the total GSL content increased significantly, ranging from 2.9-fold (mechanical damage, 3 h) to 10.7-fold (MeJA, 6 h). Moreover, 132 genes were involved in GSL metabolic pathways. Among them, no homologs of AtCYP79F2 and AtMAM3 were identified, leading to a distinctive GSL profile in I. indigotica. Furthermore, most genes involved in the GSL metabolic pathway were derived from tandem duplication, followed by dispersed duplication and segmental duplication. Purifying selection was observed, although some genes underwent relaxed selection. In addition, three tandem-arrayed GSL-OH genes showed different expression patterns, suggesting possible subfunctionalization during evolution. CONCLUSIONS: Ten different GSLs with their accumulation patterns and 132 genes involved in the GSL metabolic pathway were explored, which laid a foundation for the study of GSL metabolism and regulatory mechanisms in I. indigotica.

Glucosinolate-Enriched Fractions from Maca (Lepidium meyenii) Exert Myrosinase-Dependent Cytotoxic Effects against HepG2/C3A and HT29 Tumor Cell Lines.

The consumption of glucosinolate (GL)-rich foods, including Brassica vegetables, such as mustard, broccoli, and maca, is associated with decreased risk of developing cancer. The GL content in maca, which is recognized as a "superfood", is approximately 100-times higher than that in other brassicas. Although maca is a potential dietary source of GLs, limited studies have examined the bioactivity of maca GLs using the combination of chemical characterization and bioassays. In this study, the fractions (Lm-II and Lm-III) rich in intact GLs (glucotropaeolin and glucolimnanthin) were isolated and characterized from maca ethanolic extracts using chromatography and mass spectrometry. Additionally, the growth-inhibitory effects of Lm-II and Lm-II fractions against hepatocellular carcinoma (HepG2/C3A) and colon adenocarcinoma (HT29) cell lines were examined in the absence or presence of myrosinase (MYR). Fractions lacking low molecular weight sugars dose-dependently exerted cytotoxic effects in the presence of MYR. The half-maximal inhibitory concentration values of Lm-II and Lm-III against HepG2/C3A were 118.8 and 69.9 µg/mL, respectively, while those against HT29 were 102.6 and 71.5 µg/mL, respectively. These results suggest that the anticancer properties of maca can be attributed to GLs and corroborate the categorization of maca as a "superfood."Supplemental data for this article is available online at https://doi.org/10.1080/01635581.2021.1952444.

Dietary-Fibre-Rich Fractions Isolated from Broccoli Stalks as a Potential Functional Ingredient with Phenolic Compounds and Glucosinolates.

The Brassica oleracea industry generates large amounts of by-products to which value could be added because of the characteristics of their composition. The aim was to extract different fibre fractions from broccoli stalks to obtain potential new added-value ingredients. Using an ethanol and water extraction procedure, two fibre-rich fractions (total fibre fraction, TFB, and insoluble fibre fraction, IFB) were obtained. These fractions were analysed to determine the nutritional, (poly)phenols and glucosinolates composition and physicochemical properties, comparing the results with those of freeze-dried broccoli stalks (DBS). Although TFB showed a higher content of total dietary fibre, IFB had the same content of insoluble dietary fibre as TFB (54%), better hydration properties, higher content of glucosinolates (100 mg/100 g d.w.) and (poly)phenols (74.7 mg/100 g d.w.). The prebiotic effect was evaluated in IFB and compared with DBS by in vitro fermentation with human faecal slurries. After 48 h, the short-chain fatty acid (SCFA) production was higher with IFB than with DBS because of the greater presence of both uronic acids, the main component of pectin, and (poly)phenols. These results reveal that novel fibre-rich ingredients-with antioxidant, technological and physiological effects-could be obtained from broccoli stalks by using green extraction methods.

The Distribution of Glucosinolates in Different Phenotypes of Lepidium peruvianum and Their Role as Acetyl- and Butyrylcholinesterase Inhibitors-In Silico and In Vitro Studies.

The aim of the study was to present the fingerprint of different Lepidium peruvianum tuber extracts showing glucosinolates-containing substances possibly playing an important role in preventinting dementia and other memory disorders. Different phenotypes of Lepidium peruvianum (Brassicaceae) tubers were analysed for their glucosinolate profile using a liquid chromatograph coupled with mass spectrometer (HPLC-ESI-QTOF-MS/MS platform). Qualitative analysis in 50% ethanolic extracts confirmed the presence of ten compounds: aliphatic, indolyl, and aromatic glucosinolates, with glucotropaeolin being the leading one, detected at levels between 0-1.57% depending on phenotype, size, processing, and collection site. The PCA analysis showed important variations in glucosinolate content between the samples and different ratios of the detected compounds. Applied in vitro activity tests confirmed inhibitory properties of extracts and single glucosinolates against acetylcholinesterase (AChE) (15.3-28.9% for the extracts and 55.95-57.60% for individual compounds) and butyrylcholinesterase (BuChE) (71.3-77.2% for the extracts and 36.2-39.9% for individual compounds). The molecular basis for the activity of glucosinolates was explained through molecular docking studies showing that the tested metabolites interacted with tryptophan and histidine residues of the enzymes, most likely blocking their active catalytic side. Based on the obtained results and described mechanism of action, it could be concluded that glucosinolates exhibit inhibitory properties against two cholinesterases present in the synaptic cleft, which indicates that selected phenotypes of L. peruvianum tubers cultivated under well-defined environmental and ecological conditions may present a valuable plant material to be considered for the development of therapeutic products with memory-stimulating properties.

Rocket (Eruca vesicaria (L.) Cav.) vs. Copper: The Dose Makes the Poison?

The effects of copper addition, from various adsorbents, on the accumulation ability and glucosinolate content of cultivated rocket were studied. Different adsorbents (zeolite NaX, egg shells, substrate, fly ash) were treated with copper(II) solution with an adsorption efficiency of 98.36, 96.67, 51.82 and 39.13%, respectively. The lowest copper content and the highest total glucosinolate content (44.37 µg/g DW and 4269.31 µg/g DW, respectively) were detected in the rocket grown in the substrate with the addition of a substrate spiked with copper(II) ions. Rocket grown in the fly ash-substrate mixture showed an increase in copper content (84.98 µg/g DW) and the lowest total glucosinolate content (2545.71 µg/g DW). On the other hand, when using the egg shells-substrate mixture, the rocket copper content increased (113.34 µg/g DW) along with the total GSLs content (3780.03 µg/g DW), indicating the influence of an adsorbent type in addition to the copper uptake. The highest copper content of 498.56 µg/g DW was detected in the rocket watered with copper(II) solution with a notable decrease in the glucosinolate content, i.e., 2699.29 µg/g DW. According to these results rocket can be considered as a copper accumulator plant.

C. spinosa L. subsp. rupestris Phytochemical Profile and Effect on Oxidative Stress in Normal and Cancer Cells.

Spices, widely used to improve the sensory characteristics of food, contain several bioactive compounds as well, including polyphenols, carotenoids, and glucosynolates. Acting through multiple pathways, these bioactive molecules affect a wide variety of cellular processes involved in molecular mechanisms important in the onset and progress of human diseases. Capparis spinosa L. is an aromatic plant characteristic of the Mediterranean diet. Previous studies have reported that different parts (aerial parts, roots, and seeds) of C. spinosa exert various pharmacological activities. Flower buds of C. spinosa contain several bioactive compounds, including polyphenols and glucosinolates. Two different subspecies of C. spinosa L., namely, C. spinosa L. subsp. spinosa, and C. spinosa L. subsp. rupestris, have been reported. Few studies have been carried out in C. spinosa L. subsp. rupestris. The aim of our study was to investigate the phytochemical profile of floral buds of the less investigated species C. spinosa subsp. rupestris. Moreover, we investigated the effect of the extract from buds of C. spinosa subsp. rupestris (CSE) on cell proliferation, intracellular ROS levels, and expression of the antioxidant and anti-apoptotic enzyme paraoxonase-2 (PON2) in normal and cancer cells. T24 cells and Caco-2 cells were selected as models of advanced-stage human bladder cancer and human colorectal adenocarcinoma, respectively. The immortalized human urothelial cell line (UROtsa) and human dermal fibroblast (HuDe) were chosen as normal cell models. Through an untargeted metabolomic approach based on ultra-high-performance liquid chromatography quadrupole-time-of-flight mass spectrometry (UHPLC-QTOF-MS), our results demonstrate that C. spinosa subsp. rupestris flower buds contain polyphenols and glucosinolates able to exert a higher cytotoxic effect and higher intracellular reactive oxygen species (ROS) production in cancer cells compared to normal cells. Moreover, upregulation of the expression of the enzyme PON2 was observed in cancer cells. In conclusion, our data demonstrate that normal and cancer cells are differentially sensitive to CSE, which has different effects on PON2 gene expression as well. The overexpression of PON2 in T24 cells treated with CSE could represent a mechanism by which tumor cells protect themselves from the apoptotic process induced by glucosinolates and polyphenols.

Characterization of ultrafine zein fibers incorporated with broccoli, kale, and cauliflower extracts by electrospinning.

BACKGROUND: Broccoli, kale, and cauliflower contain phenolic compounds and glucosinolates, which have several biological effects on the body. However, because they are thermolabile, many of these substances are lost in the cooking process. Electrospinning encapsulation, using zein as a preservative wall material, can expand the applications of the compounds in the food and pharmaceutical industries. The objective of this research was to characterize broccoli, kale, and cauliflower extracts and encapsulate them with the electrospinning technique using zein. RESULTS: Broccoli, kale, and cauliflower extracts contain five phenolic compounds and three glucosinolates. Fibers from broccoli, kale, and cauliflower showed high encapsulation efficiency, good thermal stability, and nanometric size, especially those containing extract and zein in proportions of up to 35:65. CONCLUSION: Fibers from broccoli, kale, and cauliflower containing extract and zein in proportions of up to 35:65 have the potential for effective nutraceutical application for the control of non-communicable chronic diseases or application in food packaging. © 2022 Society of Chemical Industry.

[Simultaneous determination of glucosinolates and flavonoids in leaves of Moringa oleifera by quantitative analysis of multi-components by single-marker (QAMS)].

To establish a method for simultaneously determining the content of four glucosinolates and five flavonoids in leaves of Moringa oleifera via quantitative analysis of multi-components by single-marker(QAMS) and verify the feasibility and applicability of the established method. The glucosinolates and flavonoids were analyzed via Waters Acquity UPLC HSS T_3 column(2.1 mm × 100 mm, 1.8 µm). The gradient elution was carried out with the mobile phase composed of 0.1% formic acid-acetonitrile and 0.3% formic acid at the flow rate of 0.4 mL·min~(-1) and the column temperature of 40 ℃. The wavelengths for the detection of glucosinolates and flavonoids were 225 nm and 260 nm, respectively. With 4-O-(α-L-rhamnoyloxy)-benzyl glucosinolate and vecenin-2 as internal reference substances, the relative correction factors of four glucosinolates and five flavonoids were respectively calculated for determining the content of the 9 ingredients in leaves of M. oleifera. To verify the accuracy and feasibility of QAMS, we used internal standard method(ISM) and external standard method(ESM) to determine the content of glucosinolates and flavonoids, respectively. The t-test results showed that there was no significant difference in the content of glucosinolates obtained by ISM and QAMS methods or in the content of flavonoids obtained by ESM and QAMS methods. The content of glucosinolates and flavonoids varied among M. oleifera of different varieties and from different producing areas. The total glucosinolates and total flavonoids had the highest content in the Indian variety while the lowest content in the variety ■Honghe No. 1'. The established QAMS method is rapid, simple and accurate and can be used for simultaneous determination of glucosinolates and flavonoids in the leaves of M. oleifera. This study provides experimental data for the quality control and utilization of M. oleifera leaves.

The glucosinolates and their bioactive derivatives in Brassica: a review on classification, biosynthesis and content in plant tissues, fate during and after processing, effect on the human organism and interaction with the gut microbiota.

The present study is a systematic review of the scientific literature reporting content, composition and biosynthesis of glucosinolates (GLS), and their derivative compounds in Brassica family. An amended classification of brassica species, varieties and their GLS content, organized for the different plant organs and in uniformed concentration measure unit, is here reported for the first time in a harmonized and comparative manner. In the last years, the studies carried out on the effect of processing on vegetables and the potential benefits for human health has increased rapidly and consistently the knowledge on the topic. Therefore, there was the need for an updated revision of the scientific literature of pre- and post-harvest modifications of GLS content, along with the role of gut microbiota in influencing their bioavailability once they are ingested. After analyzing and standardizing over 100 articles and the related data, the highest GLS content in Brassica, was declared in B. nigra (L.) W. D. J. Koch (201.95 ± 53.36 µmol g-1), followed by B. oleracea Alboglabra group (180.9 ± 70.3 µmol g-1). The authors also conclude that food processing can influence significantly the final content of GLS, considering the most popular methods: boiling, blanching, steaming, the latter can be considered as the most favorable to preserve highest level of GLS and their deriviatives. Therefore, a mild-processing strategic approach for GLS or their derivatives in food is recommended, in order to minimize the loss of actual bioactive impact. Finally, the human gut microbiota is influenced by Brassica-rich diet and can contribute in certain conditions to the increasing of GLS bioavailability but further studies are needed to assess the actual role of microbiomes in the bioavailability of healthy glucosinolate derivatives.

Water Deficiency and Induced Defense Against a Generalist Insect Herbivore in Desert and Mediterranean Populations of Eruca sativa.

In natural and agricultural ecosystems, plants are often simultaneously or sequentially exposed to combinations of stressors. Here we tested whether limited water availability (LWA) affects plant response to insect herbivory using two populations of Eruca sativa from desert and Mediterranean habitats that differ in their induced defenses. Considering that such differences evolved as responses to biotic and possibly abiotic stress factors, the two populations offered an opportunity to study ecological aspects in plant response to combined stresses. Analysis of chemical defense mechanisms showed that LWA significantly induced total glucosinolate concentrations in the Mediterranean plants, but their concentrations were reduced in the desert plants. However, LWA, with and without subsequent jasmonate elicitation, significantly induced the expression of proteinase inhibitor in the desert plants. Results of a no-choice feeding experiment showed that LWA significantly increased desert plant resistance to Spodoptera littoralis larvae, whereas it did not affect the relatively strong basal resistance of the Mediterranean plants. LWA and subsequent jasmonate elicitation increased resistance against the generalist insect in Mediterranean plants, possibly due to both increased proteinase inhibitor expression and glucosinolate accumulation. The effect of LWA on the expression of genes involved in phytohormone signaling, abscisic acid (ABA-1) and jasmonic acid (AOC1), and the jasmonate responsive PDF1.2, suggested the involvement of abscisic acid in the regulation of defense mechanisms in the two populations. Our results indicate that specific genotypic responses should be considered when estimating general patterns in plant response to herbivory under water deficiency conditions.