Glucosinolate profile of Eruca sativa, Diplotaxis tenuifolia and Diplotaxis erucoides grown in soil and soilless systems

Improvement of the Quality of Wild Rocket (Diplotaxis tenuifolia) with Respect to Health-Related Compounds by Enhanced Growth Irradiance

For healthier human nutrition, it is desirable to provide food with a high content of nutraceuticals such as polyphenolics, vitamins, and carotenoids. We investigated to what extent high growth irradiance influences the content of phenolics, α-tocopherol and carotenoids, in wild rocket (Diplotaxis tenuifolia), which is increasingly used as a salad green. Potted plants were grown in a climate chamber with a 16 h day length at photosynthetic photon flux densities varying from 20 to 1250 μmol m-2 s-1. Measurements of the maximal quantum yield of photosystem II, FV/FM, and of the epoxidation state of the violaxanthin cycle (V-cycle) showed that the plants did not suffer from excessive light for photosynthesis. Contents of carotenoids belonging to the V-cycle, α-tocopherol and several quercetin derivatives, increased nearly linearly with irradiance. Nonintrusive measurements of chlorophyll fluorescence induced by UV-A and blue light relative to that induced by red light, indicating flavonoid and carotenoid content, allowed not only a semiquantitative measurement of both compounds but also allowed to follow their dynamic changes during reciprocal transfers between low and high growth irradiance. The results show that growth irradiance has a strong influence on the content of three different types of compounds with antioxidative properties and that it is possible to determine the contents of flavonoids and specific carotenoids in intact leaves using chlorophyll fluorescence. The results may be used for breeding to enhance healthy compounds in wild rocket leaves and to monitor their content for selection of appropriate genotypes.

Reduced Fertilization to Improve Sustainable Use of Resources and Preserve Postharvest Quality of Fresh-Cut Wild Rocket (Diplotaxis tenuifolia L.) in Soil-Bound and Soilless Cultivation

Reducing fertilizer input is a goal for helping greenhouse farming to achieve higher sustainability in the production process while preserving overall crop performance and quality. Wild rocket plants were cultivated in a plastic greenhouse divided into two independent sectors, one for soil-bound (SbS) cultivation and another equipped for soilless (ScS) cultivation systems. In both SbS and ScS, the crop was subjected to treatments consisting of a high- and a low-input fertilization program (HF and LF treatment, respectively). Water use efficiency (WUE) and partial factor productivity (PFP) for nutrients (N, P, K, Ca, and Mg for ScS, and N for SbS) were measured. Rocket leaves, separated for the cultivation system and fertilization program and collected at different cuts during the growing cycle, were cold stored at 10 °C until 16 d. On each sampling day (at harvest and during storage), the sensory parameters, respiration rate, dry matter, color, electrolyte leakage, antioxidant activity, total phenols, total chlorophyll and ammonia content were evaluated. In ScS, the PFP for all nutrients supplied as fertilizers showed a significant increase with the LF treatment, with values higher than 30% recorded for N, K, and Ca. As for the postharvest performance, rocket leaves cultivated in ScS showed better qualitative traits than those cultivated in SbS, as suggested by the lower values of ammonia content and electrolyte leakage recorded at the end of storage period in samples grown in ScS. Moreover, in ScS, the data showed lower membrane damage in LF than HF rocket leaves. Finally, regarding total chlorophyll content, even if no effect of each treatment was recorded in SbS, rocket cultivated in ScS showed a better retention of this parameter by applying LF rather than HF treatment. In addition to this, a PLS model (R2 = 0.7) able to predict the cultivation system, using as a variable non-destructively measured total chlorophyll content, was implemented. Low fertilization input, both in SbS and in ScS, allowed satisfying production levels and more sustainable management of nutrients. LF treatment applied to ScS also had in positive effects on the postharvest quality of fresh-cut rocket leaves.

Yield performance, mineral profile, and nitrate content in a selection of seventeen microgreen species

Introduction

Originally regarded as garnish greens, microgreens are increasingly valued for their nutritional profile, including their mineral content.

Methods

A study was conducted under controlled environmental conditions utilizing a selection of seventeen microgreen species belonging to seven different botanical families to investigate the genetic variation of macro- and micro-minerals and nitrate (NO3 -) content. Plants were grown in a soilless system using a natural fiber mat as the substrate. After germination, microgreens were fertigated with a modified half-strength Hoagland solution prepared using deionized water and without adding microelements. At harvest (10 to 19 days after sowing, based on the species), yield components were measured and dry tissue samples were analyzed for the concentration of total nitrogen (N), NO3 -, P, K, Ca, Mg, S, Na, Fe, Zn, Mn, Cu, and B.

Results and discussion

Genotypic variations were observed for all of the examined parameters. Nitrogen and K were the principal macronutrients accounting for 38.4% and 33.8% of the total macro-minerals concentration, respectively, followed in order by Ca, P, S, and Mg. Except for sunflower (Helianthus annuus L.), all the tested species accumulated high (1,000-2,500 mg kg-1 FW) or very high (>2,500 mg kg-1 FW) NO3 - levels. Eight of the studied species had a K concentration above 300 mg 100 g-1 FW and could be considered as a good dietary source of K. On the other hand, scallion (Allium fistulosum L.), red cabbage (Brassica oleracea L. var. capitata), amaranth (Amaranthus tricolor L.), and Genovese basil (Ocinum basilicum L.) microgreens were a good source of Ca. Among micro-minerals, the most abundant was Fe followed by Zn, Mn, B, and Cu. Sunflower, scallion, and shiso (Perilla frutescens (L.) Britton) were a good source of Cu. Moreover, sunflower was a good source of Zn, whereas none of the other species examined could be considered a good source of Fe and Zn, suggesting that supplementary fertilization may be required to biofortify microgreens with essential microminerals. In conclusion, the tested microgreens can be a good source of minerals showing a high potential to address different dietary needs; however, their yield potential and mineral profile are largely determined by the genotype.

Organic waste compost and spent mushroom compost as potential growing media components for the sustainable production of microgreens

Microgreens are emerging specialty crops becoming increasingly popular for their rich nutrient profile and variety of colors, flavors, and textures. The growing medium is a significant key factor in microgreen yield, quality, and sustainability. The widespread use of peat-based media raises questions regarding the environmental sustainability of microgreens production, and new substrates that are more sustainable are required. To this purpose, a study was designed with the objective of comparing eight alternative growing media evaluating their physicochemical properties and effect on yield, mineral profile, and nutritional quality of peas and radish microgreens. Tested substrates included a standard peat and perlite mixture (PP), coconut coir (CC), spent mushroom compost (SMC), organic waste compost (CMP), and 50:50 (v:v) mixes of PP and SMC, PP and CMP, CC and SMC, and CC and CMP. The physicochemical properties widely differed among the alternative substrates tested. SMC had high electrical conductivity and salt concentration, which resulted in poor seed germination. Growing media tested significantly influenced the production and nutritional quality of both microgreen species and variations were modulated by the species. With a 39.8% fresh yield increase or a small yield decrease (-14.9%) in radish and peas, respectively, PP+CMP (50:50, v/v) mix provided microgreens of similar or higher nutritional quality than PP, suggesting the potential of substituting at least in part peat with CMP. Using locally available CMP in mix with PP could reduce the microgreens industry reliance on peat while reducing costs and improving the sustainability of the production of microgreens. Further research is needed to evaluate also the potential economic and environmental benefits of using locally available organic materials like CMP as alternative growing media and peat-substitute to produce microgreens.

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.

The Mixing Ratio and Filling-Amount Affect the Tissue Browning and Antioxidant Properties of Fresh-Cut Baby Leaf Lettuce (Lactuca sativa L.) and Rocket (Eruca sativa Mill.) Grown in Floating Growing Systems

Different types of baby leaf vegetables (BLV) are often mixed and packaged as salad mixes. This work has evaluated the effects of BLV mixing ratios (100% lettuce ‘Lollo Bionda’, 100 LB; 75% lettuce + 25% rocket, 75 LB; 50% lettuce + 50% rocket, 50 LB) and the weight filling amount (125 g filling amount, 125F; 250 g, 250F) on the antioxidant properties and browning potential (BP) of lettuce and rocket baby leaves during storage for 9 days at 4 °C in the dark. The samples were packaged in thermos-sealed bags previously prepared using polypropylene film. The results showed that the 50 LB mix had preserved high amounts of chlorophylls and internal nutrients on d9, regardless of the filling amount. No visible browning symptoms were detected in the 50 LB samples. The 50 LB × 125F mix was found to be the most efficient strategy to maintain the antioxidant property of BLV. Thus, the optimisation of the mixing ratio and its combination with an appropriate filling amount could represent an effective postharvest practice.

Biosynthesis, distribution, nutritional and organoleptic properties of bitter compounds in fruit and vegetables

Compounds that confer a bitter taste on fruits and vegetables (FAVs) play crucial roles in both plant defense and health promotion. This review details the current knowledge of the distribution, properties (toxicity, pharmacological effects and receptors) and environmental plant responses relating to the biosynthesis, catabolism and transcriptional regulation of 53 bitter plant metabolites in diverse species of FAVs. Some bitter compounds, such as flavonoids, are common in all plant species and make a minor contribution to bitter flavor, but many are synthesized only in specific taxa. They make major contributions to the bitter taste of the corresponding species and some also have significant pharmacological effects. Levels of bitter metabolites are genetically determined, but various environmental cues can affect their final concentration during preharvest development and postharvest storage processes. Molecular approaches are helping to unravel the mechanisms of biosynthesis and regulation of bitter compounds in diverse crop species. This review not only discusses the theoretical basis for utilizing breeding programs and other agricultural technologies to produce FAVs with improved safety, favorable taste and healthier profiles, but also suggests new directions for the utilization of bitter compounds in FAVs for the development of natural pesticides and health-promoting medicines.

Biosynthesized Silver Nanoparticles from Eruca sativa Miller Leaf Extract Exhibits Antibacterial, Antioxidant, Anti-Quorum-Sensing, Antibiofilm, and Anti-Metastatic Activities

Worldwide, the primary problem today is the proliferation of cancer and secondary bacterial infections caused by biofilms, as they are the principal causes of death due to the lack of effective drugs. A great deal of biological activities of silver nanoparticles (AgNPs) have made them a brilliant choice for the development of new drugs in recent years. The present study was conducted to evaluate the anticancer, antibacterial, anti-QS, and antibiofilm effects of AgNPs synthesized from Eruca sativa (E. sativa) leaf extract. The ultraviolet–visible (UV–Vis) spectra showed a peak of surface plasmon resonance at 424 nm λmax, which corresponded to AgNP formation. The Fourier transform infrared spectroscopy (FT-IR) confirmed that biological moieties are involved for the development of AgNPs. Moreover, transmission electron microscopy (TEM) analyses confirmed the spherical shape and uniform size (8.11 to 15 nm) of the AgNPs. In human lung cancer cells (A549), the anticancer potential of AgNPs was examined by the MTT [3-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide] assay, scratch assay, and invasion assay. The results indicated that AgNPs inhibit the migration of A549 cells. The synthesized AgNPs showed MIC values of 12.5 µg/mL against Chromobacterium violaceum (C. violaceum) and 25 µg/mL against Pseudomonas aeruginosa (P. aeruginosa), which demonstrated their antibacterial abilities. Biological compounds that disable the QS system are being investigated as potential strategies for preventing bacterial infections. Thus, we analyzed the potential effectiveness of synthesized AgNPs in inhibiting QS-regulated virulence factors and biofilm formation in both strains of bacteria. In C. violaceum, the synthesized AgNPs significantly inhibited both violacein (85.18% at 1/2 × MIC) and acyl homoserine lactone (78.76% at 1/2 × MIC). QS inhibitory activity was also demonstrated in P. aeruginosa at a sub-MIC concentration (1/2 × MIC) by a reduction in pyocyanin activity (68.83%), total protease (68.50%), LasA activity (63.91%), and LasB activity (56.40%). Additionally, the exopolysaccharide production was significantly reduced in both C. violaceum (65.79% at 1/2 × MIC) and P. aeruginosa (57.65% at 1/2 × MIC). The formation of biofilm was also significantly inhibited at 1/2 × MIC in C. violaceum (76.49%) and in P. aeruginosa (65.31%). Moreover, a GC–MS analysis confirmed the presence of different classes of bioactive phytochemical constituents present in the leaf extract of E. sativa. On the basis of our results, we conclude that biologically synthesized AgNPs showed numerous multifunctional properties and have the potential to be used against human cancer and bacterial biofilm-related infections.

Cardiovascular benefits of Eruca sativa mill. Defatted seed meal extract: Potential role of hydrogen sulfide

Eruca sativa Mill. is an edible plant belonging to the Brassicaceae botanical family with a long story as a medicinal material, mainly linked to the presence of glucoerucin. One of the main products of this glucosinolate is erucin, a biologicallly active isothiocyanate recently recognized as a hydrogen sulfide (H₂S) donor. In this work, an Eruca sativa extract has been obtained from a defatted seed meal (DSM), achieving a powder rich in thiofunctionalized glucosinolates, glucoerucin, and glucoraphanin, accounting for 95% and 5% of the total glucosinolate content (17% on a dry weight basis), associated with 13 identified phenolic acids and flavonoids accounting for 2.5%. In a cell‐free model, Eruca sativa DSM extract slowly released H₂S. Moreover, this extract promoted significant hypotensive effects in hypertensive rats, and evoked dose‐dependent cardioprotection in in vivo model of acute myocardial infarct, obtained through a reversible coronary occlusion. This latter effect was sensitive to blockers of mitochondrial KATP and Kv7.4 potassium channels, suggesting a potential role of these mitochondrial channels in the protective effects of Eruca sativa DSM extract. Accordingly, Eruca sativa DSM extract reduced calcium uptake and apoptotic cell death in isolated cardiac mitochondria. Taken together, these results demonstrate that Eruca sativa DSM extract is endowed with an interesting nutraceutical profile on the cardiovascular system due to, at least in part, its H₂S releasing properties. These results pave the way for future investigations on active metabolites.

Phytochemical and In Silico ADME/Tox Analysis of Eruca sativa Extract with Antioxidant, Antibacterial and Anticancer Potential against Caco-2 and HCT-116 Colorectal Carcinoma Cell Lines

Eruca sativa Mill. (E. sativa) leaves recently grabbed the attention of scientific communities around the world due to its potent bioactivity. Therefore, the present study investigates the metabolite profiling of the ethanolic crude extract of E. sativa leaves using high resolution-liquid chromatography-mass spectrometry (HR-LC/MS), including antibacterial, antioxidant and anticancer potential against human colorectal carcinoma cell lines. In addition, computer-aided analysis was performed for determining the pharmacokinetic properties and toxicity prediction of the identified compounds. Our results show that E. sativa contains several bioactive compounds, such as vitamins, fatty acids, alkaloids, flavonoids, terpenoids and phenols. Furthermore, the antibacterial assay of E. sativa extract showed inhibitory effects of the tested pathogenic bacterial strains. Moreover, the antioxidant activity of 2,2-diphenyl-1-picrylhydrazyl (DPPH) and hydrogen peroxide (H2O2) were found to be IC50 = 66.16 μg/mL and 76.05 μg/mL, respectively. E. sativa also showed promising anticancer activity against both the colorectal cancer cells HCT-116 (IC50 = 64.91 μg/mL) and Caco-2 (IC50 = 83.98 μg/mL) in a dose/time dependent manner. The phytoconstituents identified showed promising pharmacokinetics properties, representing a valuable source for drug or nutraceutical development. These investigations will lead to the further exploration as well as development of E. sativa-based nutraceutical products.

Potential In Vitro Inhibition of Selected Plant Extracts against SARS-CoV-2 Chymotripsin-Like Protease (3CLPro) Activity

Antiviral treatments inhibiting Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) replication may represent a strategy complementary to vaccination to fight the ongoing Coronavirus disease 19 (COVID-19) pandemic. Molecules or extracts inhibiting the SARS-CoV-2 chymotripsin-like protease (3CLPro) could contribute to reducing or suppressing SARS-CoV-2 replication. Using a targeted approach, we identified 17 plant products that are included in current and traditional cuisines as promising inhibitors of SARS-CoV-2 3CLPro activity. Methanolic extracts were evaluated in vitro for inhibition of SARS-CoV-2 3CLPro activity using a quenched fluorescence resonance energy transfer (FRET) assay. Extracts from turmeric (Curcuma longa) rhizomes, mustard (Brassica nigra) seeds, and wall rocket (Diplotaxis erucoides subsp. erucoides) at 500 µg mL-1 displayed significant inhibition of the 3CLPro activity, resulting in residual protease activities of 0.0%, 9.4%, and 14.9%, respectively. Using different extract concentrations, an IC50 value of 15.74 µg mL-1 was calculated for turmeric extract. Commercial curcumin inhibited the 3CLPro activity, but did not fully account for the inhibitory effect of turmeric rhizomes extracts, suggesting that other components of the turmeric extract must also play a main role in inhibiting the 3CLPro activity. Sinigrin, a major glucosinolate present in mustard seeds and wall rocket, did not have relevant 3CLPro inhibitory activity; however, its hydrolysis product allyl isothiocyanate had an IC50 value of 41.43 µg mL-1. The current study identifies plant extracts and molecules that can be of interest in the search for treatments against COVID-19, acting as a basis for future chemical, in vivo, and clinical trials.

The Beneficial Health Effects of Vegetables and Wild Edible Greens: The Case of the Mediterranean Diet and Its Sustainability

The Mediterranean diet (MD) concept as currently known describes the dietary patterns that were followed in specific regions of the area in the 1950s and 1960s. The broad recognition of its positive effects on the longevity of Mediterranean populations also led to the adoption of this diet in other regions of the world, and scientific interest focused on revealing its health effects. MD is not only linked with eating specific nutritional food products but also with social, religious, environmental, and cultural aspects, thus representing a healthy lifestyle in general. However, modern lifestyles adhere to less healthy diets, alienating people from their heritage. Therefore, considering the increasing evidence of the beneficial health effects of adherence to the MD and the ongoing transitions in consumers’ behavior, the present review focuses on updating the scientific knowledge regarding this diet and its relevance to agrobiodiversity. In addition, it also considers a sustainable approach for new marketing opportunities and consumer trends of the MD.

Comparison of Three Domestications and Wild-Harvested Plants for Nutraceutical Properties and Sensory Profiles in Five Wild Edible Herbs: Is Domestication Possible?

In this study, five wild edible herbs traditionally consumed in the Tuscany region (Italy) were evaluated for their potential in human nutrition. The nutraceutical characterization of Rumex acetosa, Cichorium intybus, Picris hieracioides, Sanguisorba minor, and Plantago coronopus, as well as their sensory profile were reported. Additionally, a preliminary assessment of completely different domestication of the wild species (named "soilless", pot, and open field) was conducted to verify the possibility of their marketability, which is impossible if the plants are only gathered as wild. The open field domestication allowed to obtain plants with nutraceutical and sensory profiles similar to those of the wild species, especially in C. intybus, P. hieracioides, and S. minor. The pot domestication allow to obtain plants with chlorophyll and carotenoid contents close to those of the wild species, as well as a lower total phenolic and flavonoid content and ascorbic acid content than wild species. In the "soilless" method, R. acetosa and P. coronopus exhibited a high quality in terms of phytochemicals and antioxidant activity. Afterward, the sensory profile was strongly affected by the domestication in terms of the palatability, except for R. acetosa and P. coronopus, which displayed Hedonic Index (HI) values close to the consumer acceptability limit (HI = 6). A sensory profile similar to that of wild species was reported in open field domestication, whereas a worse sensory profile was reported in P. hieracioides and C. intybus domesticated using the soilless method. Finally, according to the preliminary assessment carried out in this study through an analysis of the general nutraceutical properties, S. minor was shown to be the most promising species thanks to its intrinsically highest nutraceutical properties considering the marketability of wild edible herbs as "new" functional food. However, further research on the bioavailability and bioactivity tests of nutraceutical compounds present in this species are required to confirm the findings of this study.

The Effect of Nitrogen Fertigation and Harvesting Time on Plant Growth and Chemical Composition of Centaurea raphanina subsp. mixta (DC.) Runemark

The aim of the present study was to evaluate the effect of nitrogen fertigation (0, 200, 400, and 600 ppm of total nitrogen) and harvesting time (9 March 2018 and 19 April 2018) on the plant growth, chemical composition, and bioactive properties of Centaurea raphanina subsp. mixta plants. The highest yield of fresh leaves was observed for the treatment of 200 ppm of N without compromising nutritional value. The increasing nitrogen levels resulted in an increase of α- and total tocopherols and sugars content, especially in the second harvest for tocopherols and in the first harvest for sugars. Similarly, total organic acids and oxalic acid content increased with increasing nitrogen levels in both harvests, while fatty acids composition had a varied response to the tested factors. Pinocembrin neohesperidoside and pinocembrin acetyl neohesperidoside isomer II were the most abundant phenolic compounds with the highest content being observed in the control treatment of the first and second harvest, respectively. The highest antioxidant activity was observed for the control and the 600 ppm treatments of the second harvest for the OxHLIA and TBARS assays, respectively, probably due to the high content of pinocembrin acetyl neohesperidoside isomer II and α-tocopherol, respectively. Finally, cytotoxic effects and antimicrobial properties showed a varied response depending on the treatment. In conclusion, C. raphanina subsp. mixta has low requirements of nitrogen to achieve the highest yield, while a varied response to the tested fertigation treatments and harvesting time was observed in terms of the chemical composition and the bioactive properties.

Red Light Is Effective in Reducing Nitrate Concentration in Rocket by Increasing Nitrate Reductase Activity, and Contributes to Increased Total Glucosinolates Content

Rocket cultivation is increasing to supply the expanding ready-to-eat market because of its unique taste, but crops are often over fertilized to avoid nitrogen deficiencies. This leads to nitrate accumulation in leaves, and the products of their degradation (nitrites and nitrosamines) have been related to several health problems. Nitrate concentrations in rocket and other leafy vegetables are subject to limits by the EU legislation, yet rocket holds a great nutritional value. Degradation products of glucosinolates (isothiocyanates) have been consistently linked with benefits to human health. We investigated the influence of nitrogen application (1 and 8 mM), species [Eruca sativa (L.) Cav. and Diplotaxis tenuifolia (L.) DC.] and light spectrum (full spectrum, red, blue and red + blue) on the nitrate concentration, nitrate reductase activity and glucosinolate content of rocket grown in a soil-less system. Red light decreased the nitrate concentration with respect to the blue spectrum (4,270 vs. 7,100 mg⋅kg-1 of fresh weight, respectively), but such reduction was influenced by the species and the nitrogen level (significantly higher in D. tenuifolia and with the higher concentration of N). The nitrate reductase activity increased under red light in D. tenuifolia, with the lower N concentration. Rocket is known to contain several health-promoting compounds mainly antioxidants and glucosinolates, as secondary metabolites that act as part of plant defense mechanisms. The total content of glucosinolates was mainly affected by the species (D. tenuifolia showed the highest concentrations). Our results will help growers to tailor light spectra with the aim of reducing nitrate concentration and to remain within EU legislative limits, without any detrimental influence on other qualitative parameters in rocket.

Growth temperature influences postharvest glucosinolate concentrations and hydrolysis product formation in first and second cuts of rocket salad

Rocket salad species (Diplotaxis tenuifolia and Eruca sativa; also known as E. vesicaria) are known for their high concentrations of health-related isothiocyanates, which are derived from secondary metabolites called glucosinolates. Increases in temperature due to climate change and extreme weather event frequencies over the coming decades are likely to influence not only the growth of leafy vegetables, but also their nutritional density. It is therefore essential to determine the impacts of these in order to mitigate crop losses and nutritional decline in future. Our data show there is a strong influence of pre-harvest growth temperatures on glucosinolate biosynthesis and formation of glucosinolate hydrolysis products postharvest, and that this is genotype dependent. High growth temperature (40 °C) severely retarded germination, growth, regrowth, and survival of rocket plants. Highest glucosinolate concentrations were observed in first and second cuts at 40 °C, but did not correspond to highest isothiocyanate concentrations (observed at 30 °C, second cut). Hydrolysis product formation is proportionately not as great as glucosinolate increases at 40 °C, possibly due to inhibition of enzyme function(s) at higher temperatures. These data indicate that high growth temperatures increase glucosinolate accumulation, but growth and productivity is significantly reduced. Much greater emphasis is needed for breeding cultivars tolerant to high growth temperatures in order to maximise nutritional benefits imparted by temperature stress.

Consumers acceptance and volatile profile of wall rocket (Diplotaxis erucoides)

Wall rocket (Diplotaxis erucoides) is a wild edible herb traditionally consumed in the Mediterranean regions with a characteristic, pungent flavour. However, little is known about its acceptance as a potential new crop. In the present study, an hedonic test with 98 volunteers was performed in order to evaluate the potential of wall rocket as a new crop. Three products were tested corresponding to microgreens, seedlings and baby-leaves. The volatile constituents were also studied due to their probable influence on acceptance, and compared to Dijon's mustard and wasabi. The degree of acceptance was mainly related to taste and pungency. Microgreens were well accepted, whereas seedlings and baby-leaves were mainly appreciated by individuals that enjoy pungent tastes. The purchase intent was also highly related to the acceptance of taste and pungency. The volatiles profile revealed that wall rocket was rich in allyl isothiocyanate, like mustard and wasabi. This compound may be greatly responsible of the relationship between the acceptance of mustard, wasabi and wall rocket. Microgreens displayed the highest levels of isothiocyanates, although the quantity of product tested by panellists did not probably allow the appreciation of such compounds. In baby-leaves, a significant decrease in isothiocyanates GC area and relative abundances was observed. These results suggest that wall rocket microgreens would be accepted by a significant proportion of the general public since pungency is lowly perceived in the product, despite its high levels of isothiocyanates. By contrast, baby-leaves may become a crop for a cohort of consumers that enjoy pungent flavours.

Grown to be Blue-Antioxidant Properties and Health Effects of Colored Vegetables. Part II: Leafy, Fruit, and Other Vegetables

The current trend for substituting synthetic compounds with natural ones in the design and production of functional and healthy foods has increased the research interest about natural colorants. Although coloring agents from plant origin are already used in the food and beverage industry, the market and consumer demands for novel and diverse food products are increasing and new plant sources are explored. Fresh vegetables are considered a good source of such compounds, especially when considering the great color diversity that exists among the various species or even the cultivars within the same species. In the present review we aim to present the most common species of colored vegetables, focusing on leafy and fruit vegetables, as well as on vegetables where other plant parts are commercially used, with special attention to blue color. The compounds that are responsible for the uncommon colors will be also presented and their beneficial health effects and antioxidant properties will be unraveled.

Lobularia maritima (L.) Desv. Aerial Parts Methanolic Extract: In Vitro Screening of Biological Activity

Lobularia maritima (L.) Desv. is a perennial herb growing wild in the Mediterranean basin. The aim of this work was to assess the fatty acid, terpene, phytosterol, and phenolic composition of the methanolic extract and its sub-fractions using Gas Chromatography-Mass Spectrometry (GC-MS), High-Performance Liquid Chromathography with Dioide-Array Detector (HPLC-DAD), High-Performance Liquid Chromathography-High Resolution Mass Spectrometry (HPLC-HRMS), and Electrospray Ionization Tandem Mass Spectrometry (ESI-MS/MS). The potential health benefits of this plant species have been investigated as well. The antioxidant activity was determined in vitro by means of 2,2-diphenyl-1-picrylhydrazyl (DPPH) and β-carotene bleaching tests. The inhibitory potential towards the production of the pro-inflammatory mediator nitric oxide was verified on lipopolysaccharide (LPS)-stimulated murine macrophage RAW 264.7 cell line. A remarkable inhibitory activity was observed for the dichloromethane fraction, with an IC50 value equal to 45.86 ± 1.05 μg/mL, a significant result if compared to indomethacin and the known nitric oxide synthase inhibitor NG-nitro-L-arginine methyl ester (L-NAME), used as positive controls. Moreover, the ethyl acetate fraction proved to be effective in inhibiting pancreatic lipase, an enzyme that plays a pivotal role in the gastrointestinal digestion of dietary fat, suggesting that this species could potentially be a promising source of useful compounds for the treatment of obesity.

Glucosinolate structural diversity, identification, chemical synthesis and metabolism in plants

The glucosinolates (GSLs) is a well-defined group of plant metabolites characterized by having an S-β-d-glucopyrano unit anomerically connected to an O-sulfated (Z)-thiohydroximate function. After enzymatic hydrolysis, the sulfated aglucone can undergo rearrangement to an isothiocyanate, or form a nitrile or other products. The number of GSLs known from plants, satisfactorily characterized by modern spectroscopic methods (NMR and MS) by mid-2018, is 88. In addition, a group of partially characterized structures with highly variable evidence counts for approximately a further 49. This means that the total number of characterized GSLs from plants is somewhere between 88 and 137. The diversity of GSLs in plants is critically reviewed here, resulting in significant discrepancies with previous reviews. In general, the well-characterized GSLs show resemblance to C-skeletons of the amino acids Ala, Val, Leu, Trp, Ile, Phe/Tyr and Met, or to homologs of Ile, Phe/Tyr or Met. Insufficiently characterized, still hypothetic GSLs include straight-chain alkyl GSLs and chain-elongated GSLs derived from Leu. Additional reports (since 2011) of insufficiently characterized GSLs are reviewed. Usually the crucial missing information is correctly interpreted NMR, which is the most effective tool for GSL identification. Hence, modern use of NMR for GSL identification is also reviewed and exemplified. Apart from isolation, GSLs may be obtained by organic synthesis, allowing isotopically labeled GSLs and any kind of side chain. Enzymatic turnover of GSLs in plants depends on a considerable number of enzymes and other protein factors and furthermore depends on GSL structure. Identification of GSLs must be presented transparently and live up to standard requirements in natural product chemistry. Unfortunately, many recent reports fail in these respects, including reports based on chromatography hyphenated to MS. In particular, the possibility of isomers and isobaric structures is frequently ignored. Recent reports are re-evaluated and interpreted as evidence of the existence of "isoGSLs", i.e. non-GSL isomers of GSLs in plants. For GSL analysis, also with MS-detection, we stress the importance of using authentic standards.

Mediterranean Wild Edible Plants: Weeds or "New Functional Crops"?

The Mediterranean basin is a biodiversity hotspot of wild edible species, and their therapeutic and culinary uses have long been documented. Owing to the growing demand for wild edible species, there are increasing concerns about the safety, standardization, quality, and availability of products derived from these species collected in the wild. An efficient cultivation method for the species having promising nutraceutical values is highly desirable. In this backdrop, a hydroponic system could be considered as a reproducible and efficient agronomic practice to maximize yield, and also to selectively stimulate the biosynthesis of targeted metabolites. The aim of this report is to review the phytochemical and toxic compounds of some potentially interesting Mediterranean wild edible species. Herein, after a deep analysis of the literature, information on the main bioactive compounds, and some possibly toxic molecules, from fifteen wild edible species have been compiled. The traditional recipes prepared with these species are also listed. In addition, preliminary data about the performance of some selected species are also reported. In particular, germination tests performed on six selected species revealed that there are differences among the species, but not with crop species. “Domestication” of wild species seems a promising approach for exploiting these “new functional foods”.