Cruciferous vegetables (Brassicaceae family) are a rich source of phytochemicals, in particular glucosinolates (GLS) and their hydrolysis products, isothiocyanates and nitriles. These phytochemicals may act as chemosensors, attracting insects, such as Pieris rapae, and stimulating oviposition. There is a lack of information on the concentrations of isothiocyanates and nitriles when an insect affects a Brassicaceae plant. In the current study, some GLS hydrolysis products were determined in healthy and Pieris rapae-infected organic cultivated broccoli plants, as well as the infesting insects’ larvae, using gas chromatography-mass spectrometry (GC-MS). This study investigated the following phytochemicals: phenethyl isothiocyanate (PEITC), erucin (ER), 3-(methylthio)propyl isothiocyanate (3MIC), and 1-cyano-4-(methylthio)butane (5MITN). All these components were quantified in the aerial and underground parts of the plants and were found in high concentrations in the roots. Among the phytochemicals studied, 5MITN presented the highest concentration in all the broccoli samples but was especially high in the stalks of the infected plants. Moreover, the analysis of a sample of Pieris rapae larvae, fed from the hosted broccoli, revealed the presence of PEITC and ER. These findings indicate that the infestation of broccoli with Pieris rapae may affect the distribution of PEITC, ER, 3MIC, and 5MITN throughout the plant. An extension of our study to conventional cultivated broccoli showed that the roots are indeed rich in GLS hydrolysis products.
Broccoli serves as a functional food because it can accumulate selenium (Se), well-known bioactive amino-acid-derived secondary metabolites, and polyphenols. The chemical and physical properties of Se are very similar to those of sulfur (S), and competition between sulfate and selenate for uptake and assimilation has been demonstrated. Towards an efficient agronomic fortification of broccoli florets, the working questions were whether we could overcome this competition by exogenously applying the S-containing amino acids cysteine (Cys) or/and methionine (Met), or/and the precursors of Glucosinolate (GSL) types along with Se application. Broccoli plants were cultivated in a greenhouse and at the beginning of floret growth, we exogenously applied sodium selenate in the concentration gradient of 0, 0.2, 1.5, and 3.0 mM to study the impact of increased Se concentration on the organic S (Sorg) content of the floret. The Se concentration of 0.2 mM (Se0.2) was coupled with the application of Cys, Met, their combination, or a mixture of phenylalanine, tryptophane, and Met. The application took place through fertigation or foliar application (FA) by adding isodecyl alcohol ethoxylate (IAE) or a silicon ethoxylate (SiE) surfactant. Fresh biomass, dry mass, and Se accumulation in florets were evaluated, along with their contents of Sorg, chlorophylls (Chl), carotenoids (Car), glucoraphanin (GlRa), glucobrassicin (GlBra), glucoiberin (GlIb), and polyphenols (PPs), for the biofortification efficiency of the three application modes. From the studied selenium concentration gradient, the foliar application of 0.2 mM Se using silicon ethoxylate (SiE) as a surfactant provided the lowest commercially acceptable Se content in florets (239 μg or 0.3 μmol g−1 DM); it reduced Sorg (−45%), GlIb (−31%), and GlBr (−27%); and it increased Car (21%) and GlRa (27%). Coupled with amino acids, 0.2 mM Se provided commercially acceptable Se contents per floret only via foliar application. From the studied combinations, that of Met,Se0.2/FA,IAE provided the lowest Se content per floret (183 μg or 0.2 μmol g−1 DM) and increased Sorg (35%), Car (45%), and total Chl (27%), with no effect on PPs or GSLs. Cys,Met,Se0.2/FA,IAE and amino acid mix,Se0.2/FA,IAE increased Sorg content, too, by 36% and 16%, respectively. Thus, the foliar application with the IAE surfactant was able to increase Sorg, and methionine was the amino acid in common in these treatments, with varying positive effects on carotenoids and chlorophylls. Only the Cys,Met,Se0.2 combination presented positive effects on GSLs, especially GlRa, but it reduced the fresh mass of the floret. The foliar application with SiE as a surfactant failed to positively affect the organic S content. However, in all studied combinations of Se 0.2 mM with amino acids, the Se content per floret was commercially acceptable, the yield was not affected, the content of GSLs was increased (especially that of GlRa and GlIb), and PPs were not affected. The content of GlBr decreased except for the treatment with methionine (Met,Se0.2/FA,SiE) where GlBr remained unaffected. Hence, the combination of Se with the used amino acids and surfactants can provide enhanced biofortification efficiency in broccoli by providing florets as functional foods with enhanced functional properties.
Sulforaphane (1-isothiocyanato-4-(methylsulfinyl)-butane) and iberin (1-isothiocyanato-3-methylsulfinylpropane) have attracted widespread attention due to their anti-inflammatory and cancer-preventive properties. These isothiocyanates are products of the enzymatic hydrolysis of the glucosinolates glucoraphanin and glucoiberin, which are found only in the plants of the order Brassicales. Cruciferous vegetables, such as broccoli, cabbage and cauliflower, belong to the order Brassicales, specifically, in the Brassicaceae family. Our aim was to develop an efficient and accurate method for the simultaneous determination of sulforaphane and iberin in cruciferous vegetables using Ultra-high Performance Liquid Chromatography-Quadrupole Time-of-Flight Mass Spectrometry (UPLC-Q-ToF-MS). The method was applied for the quantitative determination of these compounds in a variety of cruciferous vegetables (green and purple broccoli, white and purple cabbage, radish, turnip, arugula, watercress and cauliflower). The results showed that green and purple broccoli contained the highest levels of sulforaphane (660.14 ± 34.29 to 210.11 ± 9.76 μg g−1 dry weight), while the highest concentration of iberin was detected in purple broccoli (144.98 ± 3.56 μg g−1 dry weight). The lowest concentrations of sulforaphane and iberin were measured in watercress and radish. The differences in the content of these compounds can be attributed to the variability among Brassicaceae species, geography, season and various environmental factors.
Cruciferous vegetables are characterized by the presence of sulfur-containing secondary plant metabolites known as glucosinolates (GLS). The consumption of cruciferous vegetables such as broccoli, cabbage, rocket salad, and cauliflower has been related to the prevention of non-communicable diseases. Their beneficial effects are attributed to the enzymatic degradation products of GLS, e.g., isothiocyanates and indoles. Owing to these properties, there has been a shift in the last few years towards the research of these compounds and a wide range of methods for their extraction and analytical determination have been developed. The aim of this review is to present the sample preparation and extraction procedures of isothiocyanates and indoles from cruciferous vegetables and the analytical methods for their determination. The majority of the references that have been reviewed are from the last decade. Although efforts towards the application of eco-friendly non-conventional extraction methods have been made, the use of conventional solvent extraction is mainly applied. The major analytical techniques employed for the qualitative and quantitative analysis of isothiocyanates and indoles are high-performance liquid chromatography and gas chromatography coupled with or without mass spectrometry detection. Nevertheless, the analytical determination of isothiocyanates presents several problems due to their instability and the absence of chromophores, making the simultaneous determination of isothiocyanates and indoles a challenging task.
Consumption of cruciferous vegetables (Brassicaceae) has been associated with prevention of chronic non-communicable diseases. Unlike other plant species, they are able to accumulate the essential micronutrient selenium and synthesize seleno-compounds with additional health benefits. Biofortification of cruciferous vegetables could be a solution to combat selenium deficiency and a means to enhance their health-promoting properties. However, biofortification leads to alterations of plant metabolism from micro- and macronutrients to various types of phytochemicals. This systematic review presents factors controlling selenium addition has on nutrients and phytochemicals of cruciferous vegetables. Selenium compounds of Brassicaceae and their possible cancer-preventive properties are also presented. Literature research was performed using four known databases by keywords such as cruciferous vegetables names and selenium biofortification. Over 90 references, mainly from the last decade, have been reviewed. Findings suggest that selenium biofortification affects differently the contents of nutrients and phytochemicals and therefore the biofortification process for each crop should be designed accordingly taking into account selenium toxicity.
Auxin amide conjugates are regulators of the most important auxin, indole-3-acetic acid (IAA), which is considered responsible for many important processes within the plants. Herein, amide conjugates of IAA were synthesized employing a simple and efficient coupling method with WSCI·HCl, a water-soluble condensing reagent, in the presence of 1-hydroxybenzotriazole. IAA conjugates with 10 amino acids along with their corresponding methyl esters were prepared in excellent yields, up to 95%, aiming to facilitate their identification in plant species. Eight IAA-amino acid methyl ester conjugates are characterized here for the first time.
Auxins are signaling molecules involved in multiple stages of plant growth and development. The levels of the most important auxin, indole-3-acetic acid (IAA), are regulated by the formation of amide and ester conjugates with amino acids and sugars. In this work, IAA and IAA amide conjugates with amino acids bearing a free carboxylic group or a methyl ester group, along with some selected IAA metabolites, were studied in positive and negative electrospray ionization (ESI) modes, utilizing high-resolution mass spectrometry (HRMS) as a tool for their structural analysis. HRMS/MS spectra revealed the fragmentation patterns that enable us to identify IAA metabolites in plant extracts from eight vegetables of the Brassicaceae family using a fast and reliable ultra-performance liquid chromatography quadrupole time-of-flight mass spectrometry (UPLC-QToF-MS) method. The accurate m/z (mass to charge) ratio and abundance of the molecular and fragment ions of the studied compounds in plant extracts matched those obtained from commercially available or synthesized compounds and confirmed the presence of IAA metabolites.
Consumption of cruciferous vegetables has been associated with a low risk of developing cancer. Indole-type phytonutrients, derived from enzymatic hydrolysis of glucobrassicin, exhibit cancer-preventive properties and occur in all vegetables of the Brassicaceae family. A LC-Q-TOF-MS methodology was developed and applied in extracts from seven cruciferous vegetables allowing the rapid determination of indole-3-carbinol, indole-3-carbaldehyde, ascorbigen, indole-3-acetic acid and indole-3-acetonitrile. The novel method described herein, was validated and is characterized by low detection limits and excellent linearity. The simultaneous determination of indole-type phytonutrients in turnip and radish was performed for the first time.
Broccoli is a rich source of bioactive compounds. Among them, sulforaphane and indole-3-carbinol have attracted a lot of attention, since their consumption is associated with reduced risk of cancer. In this work, the development of an efficient and direct method for the simultaneous determination of sulforaphane and indole-3-carbinol in broccoli using UPLC-HRMS/MS is described. The correlation coefficient, and limits of detection (LOD) and quantification (LOQ) were 0.993, 0.77 mg/L and 2.35 mg/L for sulforaphane and 0.997, 0.42 mg/L, 1.29 mg/L for indole-3-carbinol, respectively. The content of sulforaphane and indole-3-carbinol varied between 72 +/- 9-304 +/- 2 mg and 77 +/- 1-117 +/- 3 mg per 100 g of fresh florets, respectively. Taking into consideration the differences in cultivar, geography, season and environmental factors, the results agreed with values published in the literature using other techniques. (C) 2017 Elsevier Ltd. All rights reserved.
The determination of total isothiocyanate content in broccoli is described using attenuated total reflectance Fourier transform infrared spectroscopy (ATR FT-IR) and partial least-squares (PLS) algorithm. The spectral region of 2150-2020 cm(-1) was used for the total isothiocyanate quantification. The correlation coefficient was 0.99992, the root-mean-square error of calibration (RMSEC) was 1.74 and the root-mean-square error of prediction (RMSEP) was 2.17. The results were compared with those obtained from an established UV-Vis spectrophotometric method. The two methods were equivalent in reproducibility and accuracy (F-test, t-test). The proposed ATR Fr-IR method is simpler and more rapid than the existing methods and constitutes a useful alternative for the determination of total isothiocyanates in broccoli. (C) 2017 Elsevier Inc. All rights reserved.
Calcium-independent phospholipase A2 (GVIA iPLA2) has recently attracted interest as a medicinal target. The number of known GVIA iPLA2 inhibitors is limited to a handful of synthetic compounds (bromoenol lactone and polyfluoroketones). To expand the chemical diversity, a variety of 2-oxoamides based on dipeptides and ether dipeptides were synthesized and studied for their in vitro inhibitory activity on human GVIA iPLA2 and their selectivity over the other major intracellular GIVA cPLA2 and the secreted GV sPLA2. Structure-activity relationship studies revealed the first 2-oxoamide derivative (GK317), which presents potent inhibition of GVIA iPLA2 (XI(50) value of 0.007) and at the same time significant selectivity over GIVA cPLA2 and GV sPLA2.
The upregulation of PGE2 by mesangial cells has been observed under chronic inflammation condition. In the present work, renal mesangial cells were stimulated to trigger a huge increase of PGE2 synthesis and were treated in the absence or presence of known PLA2 inhibitors. A variety of synthetic inhibitors, mainly developed in our labs, which are known to selectively inhibit each of GIVA cPLA2, GVIA iPLA2, and GIIA/GV sPLA2, were used as tools in this study. Synthetic sPLA2 inhibitors, such as GK115 (an amide derivative based on the non-natural amino acid (R)-γ-norleucine) as well as GK126 and GK241 (2-oxoamides based on the natural (S)-α-amino acid leucine and valine, respectively) presented an interesting effect on the suppression of PGE2 formation.
Group IVA cytosolic phospholipase A2 (GIVA cPLA2) is the rate-limiting provider of pro-inflammatory mediators in many tissues and is thus an attractive target for the development of novel anti-inflammatory agents. In this work, we present the synthesis of new thiazolyl ketones and the study of their activities in vitro, in cells, and in vivo. Within this series of compounds, methyl 2-(2-(4-octylphenoxy)acetyl)thiazole-4-carboxylate (GK470) was found to be the most potent inhibitor of GIVA cPLA2, exhibiting an XI(50) value of 0.011 mole fraction in a mixed micelle assay and an IC50 of 300 nM in a vesicle assay. In a cellular assay using SW982 fibroblast-like synoviocytes, it suppressed the release of arachidonic acid with an IC50 value of 0.6 μM. In a prophylactic collagen-induced arthritis model, it exhibited an anti-inflammatory effect comparable to the reference drug methotrexate, whereas in a therapeutic model, it showed results comparable to those of the reference drug Enbrel. In both models, it significantly reduced plasma PGE2 levels.
Group VIA calcium-independent phospholipase A2 (GVIA iPLA2) has recently emerged as an important pharmaceutical target. Selective and potent GVIA iPLA2 inhibitors can be used to study its role in various neurological disorders. In the current work, we explore the significance of the introduction of a substituent in previously reported potent GVIA iPLA2 inhibitors. 1,1,1,2,2-Pentafluoro-7-(4-methoxyphenyl)heptan-3-one (GK187) is the most potent and selective GVIA iPLA2 inhibitor ever reported with a XI(50) value of 0.0001, and with no significant inhibition against GIVA cPLA2 or GV sPLA2. We also compare the inhibition of two difluoromethyl ketones on GVIA iPLA2, GIVA cPLA2, and GV sPLA2.
The group IVA cytosolic phospholipase A2 (GIVA cPLA2) plays a central role in inflammation. Long chain 2-oxoamides constitute a class of potent GIVA cPLA2 inhibitors that exhibit potent in vivo anti-inflammatory and analgesic activity. We have now gained insight into the binding of 2-oxoamide inhibitors in the GIVA cPLA2 active site through a combination of molecular docking calculations and molecular dynamics simulations. Recently, the location of the 2-oxoamide inhibitor AX007 within the active site of the GIVA cPLA2 was determined using a combination of deuterium exchange mass spectrometry followed by molecular dynamics simulations. After the optimization of the AX007-GIVA cPLA2 complex using the docking algorithm Surflex-Dock, a series of additional 2-oxoamide inhibitors have been docked in the enzyme active site. The calculated binding affinity presents a good statistical correlation with the experimental inhibitory activity (r2 = 0.76, N = 11). A molecular dynamics simulation of the docking complex of the most active compound has revealed persistent interactions of the inhibitor with the enzyme active site and proves the stability of the docking complex and the validity of the binding suggested by the docking calculations. The combination of molecular docking calculations and molecular dynamics simulations is useful in defining the binding of small-molecule inhibitors and provides a valuable tool for the design of new compounds with improved inhibitory activity against GIVA cPLA2.
Spinal cord injury (SCI) results in permanent loss of motor functions. A significant aspect of the tissue damage and functional loss may be preventable as it occurs, secondary to the trauma. We show that the phospholipase A(2) (PLA(2)) superfamily plays important roles in SCI. PLA(2) enzymes hydrolyze membrane glycerophospholipids to yield a free fatty acid and lysophospholipid. Some free fatty acids (arachidonic acid) give rise to eicosanoids that promote inflammation, while some lysophospholipids (lysophosphatidylcholine) cause demyelination. We show in a mouse model of SCI that two cytosolic forms [calcium-dependent PLA(2) group IVA (cPLA(2) GIVA) and calcium-independent PLA(2) group VIA (iPLA(2) GVIA)], and a secreted form [secreted PLA(2) group IIA (sPLA(2) GIIA)] are up-regulated. Using selective inhibitors and null mice, we show that these PLA(2)s play differing roles. cPLA(2) GIVA mediates protection, whereas sPLA(2) GIIA and, to a lesser extent, iPLA(2) GVIA are detrimental. Furthermore, completely blocking all three PLA(2)s worsens outcome, while the most beneficial effects are seen by partial inhibition of all three. The partial inhibitor enhances expression of cPLA(2) and mediates its beneficial effects via the prostaglandin EP1 receptor. These findings indicate that drugs that inhibit detrimental forms of PLA(2) (sPLA(2) and iPLA(2)) and up-regulate the protective form (cPLA(2)) may be useful for the treatment of SCI.-Lopez-Vales, R., Ghasemlou, N., Redensek, A., Kerr, B. J., Barbayianni, E., Antonopoulou, G., Baskakis, C., Rathore, K. I., Constantinou-Kokotou, V., Stephens, D., Shimizu, T., Dennis, E. A., Kokotos, G., David, S. Phospholipase A2 superfamily members play divergent roles after spinal cord injury. FASEB J. 25, 4240-4252 (2011). www.fasebj.org
The resolution of 2-amino alcohols protected by urethane-type groups either via porcine pancreatic lipase (PPL) hydrolysis of the corresponding racemic acetates or via PPL catalyzed transesterification of racemic alcohols was studied. In both cases, Boc protecting group led to better chemical yields and enantiopurities than Z and Fmoc protecting groups. Furthermore, a simple and efficient method for the synthesis of the medicinally interesting optically pure (R)-2-aminohexadecanol was developed.
A number of allyl esters of various carboxylic acids and N-protected amino acids were synthesized and their hydrolysis by Candida antarctica lipase B and pig liver esterase was studied. In order to test the selectivity, the enzymatic hydrolysis of the corresponding methyl and ethyl esters was also examined. Both enzymes easily remove the allyl esters of monocarboxylates. The chemo- and regio-selectivity for the hydrolysis of glutamate diesters was studied, too, and it was found that the preference for the hydrolysis of a particular ester group depends not only on the ease of the hydrolysis observed for the esters of monocarboxylic acids, but also on the position (α- or γ-).
Two homoproline derivatives containing either the 5-thioxo-1,2,4-oxadiazole or the 2-oxo-1,2,3,5-oxathiodiazole bioisosteric groups, in replacement of the carboxyl group, were synthesized and their catalytic activities in Michael reactions were evaluated. The derivative containing the 5-thioxo-1,2,4-oxadiazole ring outperforms proline in the context of enantioselectivity in the reactions between beta-nitrostyrene and acetone or cyclohexanone, indicating that the conversion of the carboxylic group of homoproline to a bioisosteric heterocyclic ring leads to a superior organocatalyst.