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Today, essential oils (EOs), one of the most important natural products, have substituted pharmacologically relevant agents. Rosa damascena Mill, as an oil-bearing plant, has been widely used for this purpose. However, modern techniques to increase EOs, secondary metabolites (SMs), and chemical compounds of rose landraces have been less studied. Recently chelated Zinc (C-Zn) and chelated Iron (C-Fe) have affected SMs and EO compositions. Hence, a Split-split plot experiment on a randomized complete block design was conducted to investigate the foliar application of C-Zn (0, 1, 2, and 4 g L–1) and C-Fe (0, 1, 2, and 4 g L–1) on three landraces [Qamsar (QA), Khoy (KY), and Gounbarf (GN)]. HPLC and GC-MS analysis revealed the significant differences accrued via the foliar application of chelated fertilizers. C-Zn and C-Fe (4 g L–1) produced the highest level of proline content and phenylalanine ammonia-lyase (PAL) enzyme activity. A positive correlation was found between proline content and PAL activity. Phenolic acids (gallic, caffeic, chlorogenic, and coumaric) and flavonoids (rutin, quercetin, kaempferol, and apigenin) were found in the methanolic extract of Damask rose. The most abundant compounds in QA were nonadecane (22.43%), citronellol (12.76%), geraniol (11.23%), and heneicosane (10.18%), respectively. Results indicated that genetic diversity is probably one of the factors that can affect SMs and EO production in Damask rose landraces. Furthermore, chelated fertilizers affected phenolic acids, flavonoids, and EOs composition. Overall, C-Zn and C-Fe application on QA could increase in antioxidant activity of produced compounds and act as a suitable treatment to be used in therapeutic processes. [ABSTRACT FROM AUTHOR]

Increased market demand for Nigella sativa products necessitates the implementation of strategies to enhance biomass production. In this study, adventitious root (AR) cultures were successfully established for the first time in Nigella sativa under the influence of carbon nanotubes (CNTs). During initial optimization experiments, α-Naphthaleneacetic acid (NAA) at 2.0 mg/l exhibited the highest growth parameters for leaf explants, resulting in 83% adventitious root (AR) induction frequency and 13.3 g/l fresh biomass. Application of CNTs at concentrations ranging from 5.0 to 20.0 mg/l significantly enhanced adventitious root growth on solid MS media. Wherein, treatment T4 (CNTs: 20.0 mg/l) showed remarkable results with 93% AR induction frequency and 15.5 g/l fresh biomass. Further investigations were carried out using shake flasks, where the concentration of CNTs and the duration of pre-treatment played a crucial role in morphogenetic potential and biomass accumulation. A 4-hour pre-treatment with CNTs at a concentration of 10.0 mg/l exhibited the highest growth proliferation, achieving 82% morphogenetic potential and 17 g/l fresh biomass. In the AR cultured in liquid media, the presence of CNTs also influenced the total phenolic and flavonoid content in adventitious roots, with 2-hour and 4-hour pre-treatments resulting in higher levels compared to the 8-hour pre-treatment. Particularly, the 4-hour pre-treatment with 25.0 mg/l CNTs demonstrated the highest total phenolic content (9.0 mg/gDW) and total flavonoid content (7.0 mg/gDW). DPPH antioxidant activity increased with higher CNT concentrations (ranging from 5.0 to 25.0 mg/l) and longer pre-treatment durations. Notably, the highest activity of 90% was observed in AR maintained at 25 mg/l CNTs after an 8-hour pre-treatment. Moreover, Phenyl alanine ammonia lyase (PAL) activity in AR exhibited a decrease with higher CNT concentrations and longer pre-treatment durations. Nonetheless, the application of CNTs led to an increased accumulation of essential oils in N. sativa AR culture. The CNT5 treatment showed elevated levels of α-thujene, β-pinene, d-limonene, p-cymene, α-terpineol, carvone and β-Elemene. Notably, this treatment also exhibited significant levels of thymoquinone (19.2%), thymol (6.4%) and carvacrol (2.3%). The findings of this study have significant implications for scaling up the industrial production of metabolite-enriched germplasm of Nigella sativa. Key message: This study highlights carbon nano tubes pre-treatment's significant impact on growth parameters, biomass formation, and bioactive constituents in Nigella sativa adventitious roots. [ABSTRACT FROM AUTHOR]

Abstract Background The application of arbuscular mycorrhizal fungi (AMF) can induce the synthesis and accumulation of secondary metabolites in the tissues of host plants, thus impacting their allelopathic potential. Materials and methods The objective of this study was to determine the effect of three AMF species (Rhizoglomus intraradices, Funneliformis mosseae, Rhizoglomus fasciculatum) on photosynthetic pigments and secondary metabolites content in roots and reproductive organs of Ipomoea purpurea L., Digitaria sanguinalis L., and Solanum nigrum L. as a problematic weed species. Results Among compared weeds, the roots of D. sanguinalis associated with AMF accumulated the highest level of phenols. Higher content of flavonoids was obtained in roots of S. nigrum (7.46 mg g−1 FW) following colonization with R. intraradices. Berries of S. nigrum inoculated with R. intraradices had a higher concentration of terpenoids (21.45 mg 100 mL−1 of extract) than reproductive organs of D. sanguinalis and I. purpurea . Colonization with R. intraradices improved total phenolics in seeds of D. sanguinalis compared to the reproductive organs of other weeds. These compounds released from seeds help defend against pathogen infection, consequently increasing seed production. In addition, phenylalanine ammonia lyase enzyme activity in leaves of D. sanguinalis colonized by R. fasciculatum and F. mosseae was 55% and 67%, respectively, higher than I. purpurea plants, grown in the same condition. Conclusions Results suggest that AMF can play a crucial role in enhancing of secondary metabolites in these three weeds, thereby improving their allelopathic potential and competitive ability. Graphic Abstract

Young barley plants are a good source of bioactive compounds. This paper presents the effects of gaseous O3 (trioxygen or ozone) on the biosynthesis of compounds, determining the antioxidant potential of young barley plants. The total content of polyphenols was determined along with their profile, as well as total antioxidant potential and vitamin C content. The highest contents of these compounds were identified in young barley plants exposed to gaseous O3. The main bioactive compound, representing polyphenols, determined in the examined raw materials was saponarin (isovitexin 7-O-glucoside). The induction of increased biosynthesis of these molecules was directly linked to the modification of the activity of selected enzymes. The increased polyphenol content resulted from the modified activities of polyphenol oxidase (PPO) and phenylalanine ammonia lyase (PAL). On the other hand, the oxidative effect of ozone on barley plants was reduced, owing to the modified activities of catalases (CAT), glutathione peroxidases (SOD) and guaiacol peroxidase (GPOX). Analysis of the results showed that by applying gaseous O3 at a dose of 50 ppm for 10 min, the contents of bioactive compounds can be maximised in a residue-free way by activating oxidative stress defence mechanisms. [ABSTRACT FROM AUTHOR]

In fresh-cut vegetables, plant tissues are often challenged by (a)biotic stresses that act in combination, and the response to combinatorial stresses differs from that triggered by each individually. Phenolic induction by wounding is a known response contributing to increase products phenolic content. Heat application is a promising treatment in minimal processing, and its interference on the wound-induced response is produce-dependent. In carrot, two-combined stress effects were evaluated: peel removal vs. shredding, and heat application (100 °C/45 s) vs. shredding, on changes in total phenolic content (TPC) during 10 days (5 °C). By applying the first stress combination, a decrease in TPC was verified on day 0 (∼50%), ascribed to the high phenolic content of peels. Recovery of initial fresh carrot levels was achieved after 7 days owing to phenolic biosynthesis induced by shredding. For the second combination, changes in TPC, phenylalanine-ammonia-lyase (PAL), and peroxidase (POD) activity of untreated (Ctr) and heat-treated (HS) peeled shredded carrot samples were evaluated during 10 days. The heat-shock did not suppress phenolic biosynthesis promoted by PAL, although there was a two-day delay in TPC increments. Notwithstanding, phenolic accumulation after 10 days exceeded raw material TPC content. Also, the decrease in POD activity (30%) could influence quality degradation during storage. [ABSTRACT FROM AUTHOR]

Sulfated glycoproteins extracted for the first time from the Moroccan green seaweed Codium decorticatum were investigated for their ability to induce a natural defense metabolism in the roots and the upper leaves of tomato seedlings. The crude (AGB) and the purified fractions (AGP) were characterized chemically (Colorimetric assays) and structurally (SEC-MALS, GC-EI/MS, ATR-FTIR). The elicitor aqueous solutions (1 g/L) were applied by foliar spray and syringe infiltration into the internodal middle of 45-day-old tomato seedlings. Phenylalanine ammonia-lyase (PAL) activity, polyphenols, and lignin contents were measured in the roots and the leaves after 0 h, 12, 24, 48, and 72 h of treatment. The AGB and AGP extracts contained 37.67% and 48.38% of the total carbohydrates, respectively, and were mainly composed of galactose, glucose, arabinose, and a minor amount of xylose and rhamnose. They were characterized by an important molecular weight (Mw) > of 2000 × 103 g·mol−1 and a high degree of sulfation and protein (12–23% (w/w)), indicating that the extracted polysaccharides could be an arabinogalactan-rich protein present in the cell wall of the green seaweed C. decorticatum. Both crude and purified fractions exhibited an elicitor effect by inducing the PAL activity, the accumulation of phenolic compounds and lignin contents in the roots and the leaves of tomato seedlings. These responses were systemic in both the methods used (injection and foliar spray) and were mobilized throughout tissues that are not directly treated (roots and/or leaves). Regarding the elicitor activities, AGB and AGP presented globally similar patterns, which revealed the importance of crude extracts in the stimulation of plant immunity. These results suggest the new application of sulfated glycoprotein isolated from green seaweed in agriculture as inducers of natural defenses of plants. [ABSTRACT FROM AUTHOR]

The present study aimed to evaluate the effects of different doses of gamma radiation on some physiological characters of onion genotypes and the expression of PAL gene in the best interaction of gamma irradiation dose and onion genotype treatment. To this aim, four onion genotypes (White-Qom, White-Neyshabour, Red-Ridge-Lump, and Red-Ray-Corrugated) irradiated at 0, 30, 60, 90, 120, and 150 Gy. After four months of storage (at 10-15 °C and 70% relative humidity), the effects of gamma rays on the dry matter (DM), protein content, phenylalanine ammonia lyase (PAL) and peroxidase (POD) were investigated. In addition, the expression of PAL gene in the best interaction of gamma irradiation dose and onion genotype treatment was assessed. The result indicated that POD activity was increased by most of the gamma irradiation levels; however, the protein content and PAL activity were decreased. Moreover, dry matter content was found to be highly genotype-dependent. A linear regression (R2= 0.82) between PAL activity and gamma irradiation levels, was observed. PAL activity decreased with increasing in gamma irradiation level, while the expression rate of PAL gene was not significantly changed between irradiated and non-irradiated control, indicating that the radiation might not have direct effects on the gene regulatory elements. These results suggest that gamma irradiation could reduce the PAL activity possibly by controlling abiotic stress sources such as fungal and bacterial stresses.

Background: The application of arbuscular mycorrhizal fungi (AMF) can induce the synthesis and accumulation of secondary metabolites in the tissues of host plants, thus impacting their allelopathic potential. Materials and methods: The objective of this study was to determine the effect of three AMF species (Rhizoglomus intraradices, Funneliformis mosseae, Rhizoglomus fasciculatum) on photosynthetic pigments and secondary metabolites content in roots and reproductive organs of Ipomoea purpurea L., Digitaria sanguinalis L., and Solanum nigrum L. as a problematic weed species. Results: Among compared weeds, the roots of D. sanguinalis associated with AMF accumulated the highest level of phenols. Higher content of flavonoids was obtained in roots of S. nigrum (7.46 mg g−1 FW) following colonization with R. intraradices. Berries of S. nigrum inoculated with R. intraradices had a higher concentration of terpenoids (21.45 mg 100 mL−1 of extract) than reproductive organs of D. sanguinalis and I. purpurea. Colonization with R. intraradices improved total phenolics in seeds of D. sanguinalis compared to the reproductive organs of other weeds. These compounds released from seeds help defend against pathogen infection, consequently increasing seed production. In addition, phenylalanine ammonia lyase enzyme activity in leaves of D. sanguinalis colonized by R. fasciculatum and F. mosseae was 55% and 67%, respectively, higher than I. purpurea plants, grown in the same condition. Conclusions: Results suggest that AMF can play a crucial role in enhancing of secondary metabolites in these three weeds, thereby improving their allelopathic potential and competitive ability. [ABSTRACT FROM AUTHOR]

Sclerotium oryzae Catt. stem rot in rice is a devastating disease affecting rice productivity. Administration of sub-lethal dose (50 µM) of cadmium (Cd) against the pathogenic activity of Sclerotium oryzae on low-land rice (Oryza sativa var. Manika), was investigated. Improvement of shoot length was noticed with an increase in photosynthetic pigments, total carbohydrate, sugar, protein content in co-stressed (Cd + S. oryzae) rice as compared to the pathogen (S. oryzae) treated plant. Reduction of the fungal load was observed in co-stressed rice root tissue as evident by the SEM study. Fungus-treated rice, showed 2.4 fold reductions in protein level in 30 days after inoculation while that reduction was only 1.2 fold in co-stressed plants. In co-stressed rice Cd was traced in the root but not in shoot, leaf, panicle, and grain as evident by atomic absorption spectroscopy and Raman spectrum. An increase of stress-mediated proline (~ 4.2 fold) and other metabolites were found adjusted at co-stressed rice that might be due to Cd induced defense response in rice against S. oryzae. Downregulation of enhanced phenyl ammonia-lyase (PAL) and malondialdehyde (MDA) activity in co-stressed rice as compared to Cd treated plant justifies heavy metal (sub-lethal dose) mediated activation of the defense system of rice. A significant increase in the activity of catalase, guaiacol peroxidase, and superoxide dismutase observed in the co-stressed plant as compared to the pathogen treated plant supports the concept of cellular defense mechanism in rice. Protein band of ~ 29 kDa was disappeared in S. oryze infected rice while co-stressed rice showed a new ~ 23.5 kDa band that might be due to activation of PR-protein mediated defense in rice. The effect of low-dose Cd might be useful in providing defense in paddy crops against pathogen infection. [ABSTRACT FROM AUTHOR]

Sulfated glycoproteins extracted for the first time from the Moroccan green seaweed Codium decorticatum were investigated for their ability to induce a natural defense metabolism in the roots and the upper leaves of tomato seedlings. The crude (AGB) and the purified fractions (AGP) were characterized chemically (Colorimetric assays) and structurally (SEC-MALS, GC-EI/MS, ATR-FTIR). The elicitor aqueous solutions (1 g/L) were applied by foliar spray and syringe infiltration into the internodal middle of 45-day-old tomato seedlings. Phenylalanine ammonia-lyase (PAL) activity, polyphenols, and lignin contents were measured in the roots and the leaves after 0 h, 12, 24, 48, and 72 h of treatment. The AGB and AGP extracts contained 37.67% and 48.38% of the total carbohydrates, respectively, and were mainly composed of galactose, glucose, arabinose, and a minor amount of xylose and rhamnose. They were characterized by an important molecular weight (Mw) > of 2000 × 103 g·mol−1 and a high degree of sulfation and protein (12–23% (w/w)), indicating that the extracted polysaccharides could be an arabinogalactan-rich protein present in the cell wall of the green seaweed C. decorticatum. Both crude and purified fractions exhibited an elicitor effect by inducing the PAL activity, the accumulation of phenolic compounds and lignin contents in the roots and the leaves of tomato seedlings. These responses were systemic in both the methods used (injection and foliar spray) and were mobilized throughout tissues that are not directly treated (roots and/or leaves). Regarding the elicitor activities, AGB and AGP presented globally similar patterns, which revealed the importance of crude extracts in the stimulation of plant immunity. These results suggest the new application of sulfated glycoprotein isolated from green seaweed in agriculture as inducers of natural defenses of plants.

Unveiling and understanding differences in physiological features below the species level may serve as an essential fast-screening tool for selecting strains that can promote a specific probiotic effect. To study the intra-species diversity of Bacillus, a genus with a wide range of enzyme activities and specificity, 190 Bacillus strains were isolated from traditional Korean fermented food products. Altogether, in the preliminary safety screening, 8 of these strains were found negative for lecithinase and hemolysis activity and were selected for further investigations. On the basis of different levels of enzyme functionalities (high or low proteolytic, amylolytic, and lipolytic (PAL) activities), two Bacillus subtilis strains were selected for an in vivo study. Each of the two strains was separately administered at a level of 1 × 108 CFU per day to C57BL/6 mice that were fed 60% high-fat diet ad libitum for 8 weeks, while Xenical, an anti-obesity drug, was used as a positive control in the experimental setup. B. subtilis M34 and B. subtilis GS40a with low and high amylolytic activities, respectively, induced significantly different and contrasting physiological effects. The production of short-chain fatty acids appeared to be closely associated with a shift in the gut microbiota. [ABSTRACT FROM AUTHOR]

Sonchus arvensis L., as source of herbal medicine, is mostly collected from nature and rarely cultivated. In cultivated condition, the quality of S. arvensis might increase. The qualities of 10 accessions of S. arvensis, especially total flavonoid content and antioxidant activity, were investigated under cultivation condition. The field experiment was conducted from February to August 2016 at an organic experimental farm of IPB University, Bogor, Indonesia (6°30'-6°45' S, 106°30'-106°45' E). The experiment used randomized complete block design with 3 replications. Single factor of treatment was used, namely the accessions, comprised of 10 accessions originated from different areas in Java island. The results showed that the phytochemical contents (total flavonoid content, antioxidant activity, phenylalanine ammonia-lyase (PAL) activity, vitamin C and anthocyanin) differed among accessions. Banjararum accession seemed to be best accessions among 10 cultivated S. arvensis accessions, as indicated by the highest flavonoid content and the highest PAL activity. Sumbersekar accession had the highest antioxidant activity and also the highest vitamin C content. Cibadak accession had the lowest content of anthocyanin and vitamin C, and PAL activity. Banjararum accession showed big potential to develop as flavonoid oriented variety near future. However, further study is required to reconfirm those results stability in different seasons and locations. [ABSTRACT FROM AUTHOR]

Soybean (Glycin max L.) is one of the most important oily seeds in the world. This plant is rich in protein and unsaturated fats, and plays a significant role in human health with phenolic compounds and flavonoids. Indole Butyric Acid (IBA) is a plant growth regulator that plays a key role in producing phenolic compounds and increasing the antioxidant capacity of the plant. Thiamine is one of the important vitamins in strengthening the immune system and increasing the resistance to environmental stresses in the plant's growth stages. Regarding the effect of hormone auxin and thiamine on the production of phenolic compounds as one of the antioxidant compounds in growth stages, the aim of this study was to investigate the effect of the two compounds in two stages of soybean growth and compare their effect on phenolic compounds changes in order to Detecting higher antioxidant capacity in environmental stress tolerance. For this purpose, the DPX cultivar of soybean seeds were prepared from Dezful Agriculture Research Center and planted in perlite containing flowers. The plants were planted under factorial design under IBA treatments with three concentrations of 0, 10 and 50 and thiamine with three concentrations of 0, 50 and 200. Extraction and evaluation of phenolic compounds, anthocyanins and pigments in leaves were performed. Data were analyzed using Duncan's test at a significant level of 5%. The results showed that the combined use of auxin and thiamine increased the carotenoid content in both phases and caused a significant increase in phenolic content. Application of auxin alone reduced auxin and thiamine the anthocyanin content significantly in both phases, but did not have a significant effect on phenolic content. The results showed that the PAL activity of the phenolic and anthocyanin content increased significantly in the 9-leaf stage compared to 3-leaf. Generally, the results showed that interaction effect between auxin and thiamine on phenolic compounds in different stages of vegetative growth significantly improved and increased plant defense.

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This study evaluated the chemical compositions of the leaves and fruits of eight black pepper cultivars cultivated in Pará State (Amazon, Brazil). Hydrodistillation and gas chromatography–mass spectrometry were employed to extract and analyze the volatile compounds, respectively. Sesquiterpene hydrocarbons were predominant (58.5–90.9%) in the cultivars “Cingapura”, “Equador”, “Guajarina”, “Iaçará”, and “Kottanadan”, and “Bragantina”, “Clonada”, and “Uthirankota” displayed oxygenated sesquiterpenoids (50.6–75.0%). The multivariate statistical analysis applied using volatile composition grouped the samples into four groups: γ-Elemene, curzerene, and δ-elemene (“Equador”/“Guajarina”, I); δ-elemene (“Iaçará”/“Kottanadan”/“Cingapura”, II); elemol (“Clonada”/“Uthirankota”, III) and α-muurolol, bicyclogermacrene, and cubebol (“Bragantina”, IV). The major compounds in all fruit samples were monoterpene hydrocarbons such as α-pinene, β-pinene, and limonene. Among the cultivar leaves, phenolics content (44.75–140.53 mg GAE·g−1 FW), the enzymatic activity of phenylalanine-ammonia lyase (20.19–57.22 µU·mL−1), and carotenoids (0.21–2.31 µg·mL−1) displayed significant variations. Due to black pepper’s susceptibility to Fusarium infection, a molecular docking analysis was carried out on Fusarium protein targets using each cultivar’s volatile components. F. oxysporum endoglucanase was identified as the preferential protein target of the compounds. These results can be used to identify chemical markers related to the susceptibility degree of black pepper cultivars to plant diseases prevalent in Pará State.

Polysaccharides extracted from marine algae have attracted much attention due to their biotechnological applications, including therapeutics, cosmetics, and mainly in agriculture and horticulture as biostimulants, biofertilizers, and stimulators of the natural defenses of plants. This study aimed to evaluate the ability of alginate isolated from Bifurcaria bifurcata from the Moroccan coast and oligoalginates derivatives to stimulate the natural defenses of tomato seedlings. Elicitation was carried out by the internodal injection of bioelicitor solutions. The elicitor capacities were evaluated by monitoring the activity of phenylalanine ammonia-lyase (PAL) as well as polyphenols content in the leaves located above the elicitation site for 5 days. Alginate and oligoalginates treatments triggered plant defense responses, which showed their capacity to significantly induce the PAL activity and phenolic compounds accumulation in the leaves of tomato seedlings. Elicitation by alginates and oligoalginates showed an intensive induction of PAL activity, increasing from 12 h of treatment and remaining at high levels throughout the period of treatment. The amount of polyphenols in the leaves was increased rapidly and strongly from 12 h of elicitation by both saccharide solutions, representing peaks value after 24 h of application. Oligoalginates exhibited an effective elicitor capacity in polyphenols accumulation compared to alginate polymers. The alginate and oligosaccharides derivatives revealed a similar elicitor capacity in PAL activity whereas the accumulation of phenolic compounds showed a differential effect. Polysaccharides extracted from the brown seaweed Bifurcaria bifurcate and oligosaccharides derivatives induced significantly the phenylpropanoid metabolism in tomato seedlings. These results contribute to the valorization of marine biomass as a potential bioresource for plant protection against phytopathogens in the context of eco-sustainable green technology.

Shelf life of horticultural commodities is dependent on postharvest handling but also on a wide range of pre-harvest factors, which include genetic and environmental parameters. This study was conducted to explore the influence of cultivar, leaf position, and piece position on the leaf on visual quality of fresh-cut butterhead lettuce as well as the effect of a wide range of cultivation seasons on the postharvest quality and shelf life of baby leaves (spinach and ‘wild’ rocket). Six butterhead lettuce cultivars were used (cultivated soilless in an unheated plastic greenhouse) while the effect of leaf position on the plant (outer and inner leaves) and the piece position on the leaf (piece one close to the leaf base and piece four close to the top) were also evaluated. Baby leaves were cultivated under an unheated plastic greenhouse for winter production and under a nethouse for the rest of the growing season, with a total of five and seven sampling dates for spinach and ‘wild’ rocket respectively. The cultivar of butterhead lettuce had a significant effect on postharvest quality of fresh-cut product but more important was the piece position on the leaf. When this was closer to the base of the leaf, there was more browning on cut edges and limited shelf life for the fresh-cut lettuce. The result was associated in one tested cultivar with PAL activity, which was higher by 106% for piece one compared to piece four as an average for the whole storage period. The growing season of baby leaves had a great impact on their shelf life, with the season of mild environmental conditions achieving the highest marketability.

Salinity is one of the important environmental factors that limit plant growth and product. Grapes are classified as salt sensitive plants. This paper attempts to evaluate the salinity effects on membrane lipid peroxidation, antioxidant components and antioxidative enzymes activity in four grape genotypes (Vitis vinifera L., Gharashani, LaaleBidaneh, Sachagh and Shahroodi) that commonly grow in the regions around Urmia Salt Lake. We came to the conclusion that malondialdehyde content and antioxidative enzymes activity increased significantly (P

Total phenol, total flavonoid, rutin and quercetin contents as well as antioxidant activity in ethanol extracts of common buckwheat (Fagopyrum esculentum Moench) and tartary buckwheat (Fagopyrum tararicum Gaertn) sprouts were determined, and the phenylalanine ammonia-lyase (PAL) activity in the sprouts were estimated. Total flavonoid content and rutin in the sprouts of both buckwheat species gradually increased and reached the maximum levels on days 7 and 9 of germination, respectively; total phenol and free phenylalanine content also had the same trend. However, quercetin in tartary buckwheat decreased from day 5 and became undetectable on day 7, similar to that observed in common buckwheat sprouts beyond the germinating period. An obvious positive linear relationship (r2 = 0.9792, P

Pink discoloration is one of the major quality issues occurring in fresh-cut lettuce. Low oxygen atmosphere in modified atmosphere packaging prevents pinking but may lead to other major quality losses such as fermentation, growth of lactic acid bacteria and associated production of off-odours. The application of mild heat-shock treatment on fresh-cut lettuce is known to reduce the activity of Phenylalanine Ammonia Lyase (PAL), an enzyme involved in pink discoloration. Heat-shock treatment, however, may also affect the vitality of the plant tissue, leading to early senescence symptoms. In the present study several heat-shock treatments were tested for their effect on pink discoloration and on lettuce tissue vitality. The optimal heat-shock treatment was found within a narrow range of temperatures (between 45 and 47.5 °C) and application times (between 30 and 180 s). Heat-shock treatment reduced significantly the PAL activity by a factor 3 during the first 5 d of storage but increased the respiration rate of the produce by a factor 2 on day 5. We recommend to optimize the packaging to suit the heat-shock associated higher respiration rate of the treated product in order to increase the shelf life of the fresh-cut lettuce. [ABSTRACT FROM AUTHOR]

Bared-nut (Juglans regia L) cultivars, in which the endocarp or the shell has poor development or less lignification, were characterized to determine endocarp development. The bared nut ("WEN138") and normal walnuts were sampled and tested. Fruit were sampled at several times from 50d to 92d, and three key secondary enzymes in lignin pathway were analyzed via testing the activities. The results showed that final lignin contents was lower in "WEN138" (23.2%) occurring on days of 92d than in the other cultivars (average 26.2%). The activities of phenylalanine ammonia lyase (PAL) and peroxidase (POD) reaching the peak on 64 days after full blossom, were identified with "WEN185", "XINXIN2", and "ZHIPI", and in contrast, there were no clear peaks of POD and PAL activity in "WEN138". As the signals of secondary lignin metabolism, PAL expression were investigated and demonstrated the maximal PAL expression on 71 days in "WEN138", "XINXIN2", and "ZHIPI". However, the peak lightness of PAL expression in "WEN185" was on 85d. A proposed conclusion is that baredwalnut phenotype due to lignification does not effectively take place in bared nut. The economic potential of doing the same for stone fruit is to apply this marketing possibilities for cultivating thin shell cultivars of almonds and apricot, coupled with decreased production costs for intensive processing. [ABSTRACT FROM AUTHOR]

In rainfed rice cultivation, severe blast (Magnaporthe oryzae) infection is frequently observed following intermittent drought. We simulated the natural rainfed rice field and explored the complex transcriptional regulations behind enhanced susceptibility of rice towards blast disease. We identified eight new OsWRKY genes in the indica subspecies of rice using the updated v5.0 PlantTFDB and GRAMENE making it altogether 109 OsWRKY genes. Distribution of the OsWRKY genes in the 12 chromosomes of indica rice was uneven. Where, chromosome 1 houses maximum number of genes but chromosome 5 has the highest gene density. Motif analysis depicted presence of a new motif i.e., an autophagy protein 16 (ATG16) associated to group IIa of the OsWRKY genes. We selected twenty biotic stress-responsive OsWRKY genes to check their transcript accumulation pattern in individual and overlapping challenges of blast and drought in three indica rice cultivars viz., blast susceptible HR-12, and blast resistant Tetep (Pi54) and C101A51 (Pi2). Transcripts of most OsWRKY genes in the resistant cultivars accumulated early (6 h) and at higher levels compared to the susceptible check. Interestingly, a significant decrease in transcript accumulation of most of the blast responsive OsWRKY genes was observed in all the three cultivars when exposed to the overlapping challenges. Additionally, a significant reduction in biosynthesis of both the defense enzymes PAL and PO in blast and drought overlapped condition in the resistant cultivars indicated partial breakdown of resistance due to intermittent drought. To conclude, the present study has contributed to understanding of the relationship between the expression pattern of 20 biotic stress responsive OsWRKY genes in indica rice grown in rainfed condition coupled with intermittent drought and blast susceptibility. • Expression of 20 stress-responsive OsWRKY genes in indica rice genome analyzed. • Expression of OsWRKYs decreased in blast and drought overlapped condition. • PAL and PO activities also reduced in blast and drought overlapped condition. • Blast susceptibility enhanced in rice genotypes pre-disposed to intermittent drought. [ABSTRACT FROM AUTHOR]

Phenylalanine ammonia lyase (PAL) is a biochemical marker of the environmental stress and plays a pivotal role in phenolic synthesis. The lower ROS level and oxidative damage was observed in grafted plants and the rootstocks have a profound influence on the biochemical composition, especially phenolic compounds. Regarding the importance of the effect rootstocks have on scion in pistachio trees, this study was carried out to assess and compare three pistachio cultivars ("Ahmadaghaii", "Ohadi" and "Kallehghuchi") on three rootstocks (Mutica, Ahli, Sarakhs). PAL activity, phenolic compounds, flavonoid and anthocyanin contents in leaves, flowers and fruits were measured toward the selection of the most suitable and compatible rootstock/scion resistant to environmental stresses. The results showed that PAL activity was different among the cultivars and organs. A positive correlation was observed between PAL activity and phenolic compounds in the leaves and flowers of Mutica- Ahmadaghaii, suggesting that it is more resistant than the others to environmental stresses. PAL activity and total phenolics in fruits of pistachio suffered a decrease when the maturation processes began. The hulls of the pistachio fruits contained high levels of phenolic compounds especially in Mutica-Ahmadaghaii) suggesting its function as a protective layer and a defense chemical against ultraviolet radiation and pathogen. Our results indicated the presence of a number of bioactive compounds in kernels with the highest amount belonging to Mutica- Ahmadaghaii, and therefore it is concluded that pistachio rootstocks may affect the antioxidant compounds in kernels.

A randomized complete block design experiment was designed to characterize the relationship between production of total flavonoids and phenolics, anthocyanin, photosynthesis, maximum efficiency of photosystem II (Fv/Fm), electron transfer rate (Fm/Fo), phenyl alanine lyase activity (PAL) and antioxidant (DPPH) in Labisia pumila var. alata, under four levels of irradiance (225, 500, 625 and 900 µmol/m2/s) for 16 weeks. As irradiance levels increased from 225 to 900 µmol/m2/s, the production of plant secondary metabolites (total flavonoids, phenolics and antocyanin) was found to decrease steadily. Production of total flavonoids and phenolics reached their peaks under 225 followed by 500, 625 and 900 µmol/m2/s irradiances. Significant positive correlation of production of total phenolics, flavonoids and antocyanin content with Fv/Fm, Fm/Fo and photosynthesis indicated up-regulation of carbon-based secondary metabolites (CBSM) under reduced photoinhibition on the under low light levels condition. At the lowest irradiance levels, Labisia pumila extracts also exhibited a significantly higher antioxidant activity (DPPH) than under high irradiance. The improved antioxidative activity under low light levels might be due to high availability of total flavonoids, phenolics and anthocyanin content in the plant extract. It was also found that an increase in the production of CBSM was due to high PAL activity under low light, probably signifying more availability of phenylalanine (Phe) under this condition.

The activity of phenylalanine ammonia-lyase (PAL) required for anthocyanin synthesis was stimulated by sunlight exposure resulting in the development of red colour in ‘Mahajanaka’ mango exocarp, which occurred only on the sunlight-exposed side of the fruit. The accumulation of anthocyanin was concurrent with the increase in PAL activity in the mature stage of the fruit. The exposed side of the fruit had higher PAL activity, endogenous sugar content, and anthocyanin accumulation than the unexposed side. It is concluded that sunlight increases red colour development of the mango exocarp by inducing PAL activity. Exposure to sunlight also enhances endogenous sugar accumulation in mango fruit.

Salinity is one of the most important environmental factors that affect the plants growth and phytochemical compounds. So, this study was aimed to investigate the effect of salinity stress (15 mM, 30 mM, and 60 mM NaCl) and different NO 3 −/NH 4 + ratios (90:10; 80:20, and 70:30) on Echinacea purpurea properties in greenhouse conditions. A wide range of morphological properties and phytochemical compounds were determined based on the standard methods. Essential oil analyses was performed by using GC-Mass spectrometer. According to the results, plant height, total biomass, and fresh root weight decreased by 49.6, 43.2, 40.5% after the application of 60 mM NaCl, compared with control plants. However, an increase in total leaf phenolic content, flavonoid content, PAL enzyme activity, super oxide, and nitric oxide anti-radical scavenging activities by 44, 37.2, 57.9, 46, and 27.2% were found in plants grown under 30 mM NaCl salt stress conditions, respectively compared with control plants. The major terpene hydrocarbons found in the E. purpurea extract were germacrene D (60.3%), myrcene (19.8%), α-pinene (13.1%), β-caryophyllene (12.3%), and 1-Pentadecene (5.1%), respectively. It can be concluded that, 30 mM NaCl and 90:10 NO 3 −/NH 4 + ratio are effective for improving phytochemical properties of E. purpurea. • The highest phytochemicals were found in 30 mM NaCl salinity level. • Germacrene D was found as the most abundant terpene. • 60 mM NaCl salinity level decreased the plant yield. • 90:10 NO 3 −/NH 4 + increased the essential oil content. [ABSTRACT FROM AUTHOR]

Highlights: [•] Rutin and quercetin contents in germinating buckwheat seeds were monitored. [•] Correlations between PAL activity and flavonoid/phenol content were analyzed. [•] The antioxidant activity in buckwheat sprouts extracts were evaluated. [•] Findings suggest that buckwheat sprouts are a good health-promoting food sources. [Copyright &y& Elsevier]

This study was conducted to determine the effects of UV-A and UV-B wavelengths on the growth and content of antioxidant phenolic compounds in sowthistle ( Ixeris dentata Nakai), a medicinal plant, grown in a closed plant-production system. In study I, sowthistle plants were continuously exposed to UV-A light. In study II, two UV treatments [repeated UV-B (R): 4 h·d for 6 days, gradual UV-B (G): from 1 to 7 h·d for 6 days] were applied to the sowthistle plants. As a result, contents of total phenolics and antioxidants in UV-A-treated plants were significantly (50 and 30%, respectively) higher than those in the control plants after 3 d of UV treatment without growth inhibition. Moreover, plants continuously exposed to UV-A for 5 d had 50% higher total flavonoid content than the control. The phenylalanine ammonia-lyase (PAL) activity supported the accumulation of phytochemicals in plants exposed to UV-A. The UV-B (R) treatment led to a more rapid decrease in the chlorophyll fluorescence ratio than UV-B (G) treatment. The UV-B (R) or UV-B (G) treatment produced more total phenolics, flavonoids, and antioxidants, although both UV-B treatments significantly inhibited plant growth measured at 2 days after treatment. The UV irradiation also enhanced PAL activity at 2 and 3 days after treatment, suggesting biosynthetic activation of secondary metabolites. Therefore, application of UV-A or UV-B light can be used as a strategy to improve antioxidant phenolic compounds of sowthistle plants grown in closed plant production systems. [ABSTRACT FROM AUTHOR]

Phenylalanine ammonia-lyase (PAL) is a biochemical marker of environmental stress and plays a pivotal role in phenolic synthesis. Lower ROS levels and oxidative damage were observed in grafted plants; moreover, the rootstocks have a profound influence on the biochemical composition, especially of phenolic compounds. Regarding the importance of the effect rootstocks have on scion in pistachio trees, this study was carried out to assess and compare three pistachio cultivars (Ahmadaghaii, Ohadi and Kallehghuchi) on four rootstocks (Mutica, Ahli, Sarakhs and Atlantica). PAL activity, phenolic compounds, and flavonoid and anthocyanin contents in leaves, flowers and fruits were measured for the selection of the most suitable and compatible rootstock/scion resistant to environmental stresses. The results showed that PAL activity was different among the cultivars and organs. A positive correlation was observed between PAL activity and phenolic compounds in the leaves and flowers of Mutica-Ahmadaghaii, suggesting that it was more resistant than the others to environmental stresses. PAL activity and total phenolics in pistachio fruits suffered a decrease when the maturation processes began. The hulls of the pistachio fruits contained high levels of phenolic compounds, especially in Mutica-Ahmadaghaii, suggesting its function as a protective layer and a defense chemical against ultraviolet radiation and pathogens. Our results indicated the presence of a number of bioactive compounds in kernels with the highest amount belonging to Mutica-Ahmadaghaii. Therefore, we concluded that pistachio rootstocks mighy affect the antioxidant compounds in kernels. [ABSTRACT FROM AUTHOR]

The effects of l-phenylalanine (PHE) on cell growth and production of shikonin and its derivatives, acetylshikonin (ACS) and isobutyrylshikonin (IBS), in suspension cultures of Arnebia euchroma were examined. Supplementing media using PHE have been successfully utilized to enhance shikonin production in cell cultures of other species of Boraginaceae. l-Phenylalanine, the key compound in the phenylpropanoid pathway, is converted by phenylalanine ammonia lyase (PAL) to trans-cinnamic acid, which is the precursor of p-hydroxybenzoic acid (PHB). Coupling of PHB and geranyl pyrophosphate (derived from mevalonate pathway) by p-hydroxybenzoate- m-geranyltransferase leads later to biosynthesis of shikonins. The addition of 0.01 or 0.1 mM PHE to the culture medium stimulated cell proliferation, where the highest observed increase in fresh cell biomass (measured as a ratio of final weight to initial weight) was 12-fold, in contrast to an eightfold increase in control cultures. Whereas, growth media supplemented with 1 mM PHE markedly reduced the rate of cell growth (to only twofold). Precursor feeding had detrimental effects on both ACS and IBS production in all PHE-supplemented media. The highest total content (intracellular + extracellular) of the investigated red pigments (9.5 mg per flask) was detected in the control culture without PHE. ACS was the major component of the naphthoquinone fraction determined in cells and post-culture media. Shikonin itself was found only in the post-culture media from cultures supplemented with 0.01 or 0.1 mM PHE. Increases in PAL activity corresponded well with the accumulation of investigated naphthoquinones in control culture. However, peak PAL activity did not directly correlate with maximum production of shikonin derivatives. Cytotoxicity of extracts, prepared from the cells cultivated in the presence of PHE or in control cultures, was tested on three cancer cell lines: HL-60, HeLa, and MCF-7. The extracts prepared from the untreated control cultures proved to be the most potent against the examined cancer cell lines. The mean inhibitory concentration values were 0.3, 13, and 8 μg ml for the HL-60, HeLa, and MCF-7 cells, respectively. [ABSTRACT FROM AUTHOR]

Abstract: A large number of studies have estimated phenylalanine ammonia-lyase (PAL) activity because it strongly reacts to various stimuli. Activity of this enzyme has been assayed mainly by means of spectrophotometry, but the precision of this method is poorly known. We compared assays of PAL activity using spectrophotometry and high performance liquid chromatography (HPLC) in two species (Matricaria chamomilla and Arabidopsis thaliana). Additionally, copper-exposed M. chamomilla plants and buffer with additive were also tested. Our data indicate that spectrophotometry both overestimates (leaves of M. chamomilla) and underestimates (leaves and roots of A. thaliana) PAL activity in comparison with HPLC, suggesting interference of UV-absorbing metabolites. HPLC also showed more accurate detection of cinnamic acid in Cu-exposed chamomile roots. Addition of dithiothreitol to the extraction buffer enhanced PAL activity but reduced proteins, indicating an artificial negative effect. A comparison of PAL activity in selected species is also provided. [Copyright &y& Elsevier]

Gamma irradiation of seeds is known to be an important factor in stimulating biochemical and physiological processes. The aim of the present study was to investigate phenylpropanoids and associated enzymes responsible for the production of active metabolites. Furanocoumarin content was estimated in seeds of Psoralea corylifolia L. during two successive generations (G and G) where as phenylalanine ammonia lyase (PAL) activity was measured in leaves at different developmental stages of P. corylifolia L. raised from seeds irradiated with variable doses of gamma rays. Maximum accumulation of psoralen and isopsoralen was observed at 15 and 20 kGy doses during G and G generations, respectively. Psoralen proved to be the dominating metabolite in terms of its concentration, while isopsoralen was accumulated at relatively lower concentrations in successive generations. PAL activity was induced maximally following 15 and 20 kGy in G plants and was preceded by psoralen and isopsoralen accumulation which peaked at the same dose rates in both generations. These effects were transmitted and prevalent in the next generation, that is, G (indirectly irradiated). These long-term changes in plant metabolomics demonstrate genomic instability induced by gamma irradiation. However, no detrimental effects were seen at any irradiation dose in seeds. Furanocoumarin concentrations were also enhanced at 15 and 20 kGy. The present study further points out the persistence of changes in the biosynthesis of coumarin derivatives in the next generation. However, accumulation of these metabolites does not lead to any lethal effects. [ABSTRACT FROM AUTHOR]

A randomized complete block design experiment was designed to characterize the relationship between production of total flavonoids and phenolics, anthocyanin, photosynthesis, maximum efficiency of photosystem II (Fv/Fm), electron transfer rate (Fm/Fo), phenyl alanine lyase activity (PAL) and antioxidant (DPPH) in Labisia pumila var. alata, under four levels of irradiance (225, 500, 625 and 900 µmol/m2/s) for 16 weeks. As irradiance levels increased from 225 to 900 µmol/m2/s, the production of plant secondary metabolites (total flavonoids, phenolics and antocyanin) was found to decrease steadily. Production of total flavonoids and phenolics reached their peaks under 225 followed by 500, 625 and 900 µmol/m2/s irradiances. Significant positive correlation of production of total phenolics, flavonoids and antocyanin content with Fv/Fm, Fm/Fo and photosynthesis indicated up-regulation of carbon-based secondary metabolites (CBSM) under reduced photoinhibition on the under low light levels condition. At the lowest irradiance levels, Labisia pumila extracts also exhibited a significantly higher antioxidant activity (DPPH) than under high irradiance. The improved antioxidative activity under low light levels might be due to high availability of total flavonoids, phenolics and anthocyanin content in the plant extract. It was also found that an increase in the production of CBSM was due to high PAL activity under low light, probably signifying more availability of phenylalanine (Phe) under this condition. [ABSTRACT FROM AUTHOR]

2-Aminoindan-2-phosphonic acid (AIP), a specific competitive phenylalanine ammonia lyase ( PAL) inhibitor was applied to a suspension cell culture of Cistanche deserticola. The effects of AIP treatment on cell growth, PAL activity, contents and yields of total phenolic compound, salidroside and four phenylethanoid glycosides (PheGs) are investigated. The results demonstrated that, 0.5 and 2.0 μM AIP treatments had similar effects on the measurements investigated in this study. AIP treatment resulted in significant decreases in PAL activity, total phenolic compounds content, and PheGs content. Linear regression analysis showed that PAL activity had a high correlation coefficient with the total phenolic compound content and the four PheGs contents. Total PAL activity-time area under curve (AUC) had a high correlation coefficient with the total phenolic compound yield and the yields of five tested compounds in untreated cell samples. In AIP-treated cells, total PAL activity-time AUC retained a high correlation with the total phenolic compound yield and the yields of three tested compounds, echinacoside, acteoside, and tubuloside A, but not salidroside and cistanoside A. The difference could be caused by the different biosynthetic origins of each of the tested compounds. These results demonstrate the important role of PAL in the biosynthesis of PheGs in the suspension cell culture of C. deserticola. [ABSTRACT FROM AUTHOR]

Abstract: Effect of medium dose gamma irradiation on PAL and antioxidant activity of peach fruit was investigated. Peach fruit after harvest at commercial maturity was irradiated in the dose range 1.0–2.0kGy, stored under refrigerated conditions (3±1°C, RH 80%) and evaluated at intervals of 7 days. The antioxidant activity as determined by DPPH and FRAP methods revealed significant (p≤0.05) increase particularly in the dose range 1.6–2.0kGy. During storage, maximum increase in both PAL and antioxidant activity was observed after 21 days. Positive correlation (r=0.75) existed between antioxidant activity and total phenols. EC50 values as obtained from DPPH and FRAP experiments were significantly (p≤0.05) lower in irradiated fruits compared to control. [Copyright &y& Elsevier]

Abstract: Five different potato cultivars (‘Agata’, ‘Agria’, ‘Almera’, Marabel’ and ‘Vivaldi’) were cut and stored at two temperatures (5 and 20°C) for 9d in order to investigate their browning potential and their suitability to be processed as fresh-cut product on the basis of their initial quality attributes such as color, water content, polyphenol oxidase (PPO) and phenylalanine ammonia-lyase (PAL) activities, total phenolics, ascorbic acid contents, sugar composition and antioxidant activity (AOX). In addition, color changes and general appearance were monitored during storage. ANOVA results showed that the five cultivars were characterized by different initial color and yellow intensity with b* decreasing significantly from ‘Marabel’ (30.6), to ‘Agria’ (28.0), ‘Almera’ (21.6), ‘Vivaldi’ (19.6), and ‘Agata’ (16.5). Initial composition varied widely among cultivars and accounted for the different post-cutting performances. ‘Marabel’ and ‘Agata’ potatoes showed least color changes among the five cultivars, and scored the maximum for appearance when stored at 5°C, while ‘Marabel’ received the highest score also when stored at 20°C. ‘Marabel’ showed a relatively low phenol content (32.5mg GE/100g fw), low PPO activity (10.02U/g fw), one of the highest antioxidant activities (18.02mg TE/100g fw) and the highest soluble sugar content (2.3g/100g fw). ‘Vivaldi’ and ‘Agria’ cultivars showed an intermediate potential in terms of storability and appearance, while ‘Almera’ was the less suitable cultivar to be used as fresh-cut, despite its high content in ascorbic acid (34.8mg/100g fw) and high antioxidant activity (23.2mg TE/100g fw), also showing one of the highest phenol content (46.1mg GE/100g fw) and PPO activity (14.7U/g fw). A principal component analysis on the chemical and physical attributes showed a high correlation between phenol content, PAL and PPO activity, a* value, and hue angle variation at 5 and 20°C. Appearance score, and fructose and glucose contents were positively correlated with each other and inversely correlated with hue angle variation. Score, and fructose and glucose contents allowed discrimination between ‘Marabel’ and the other varieties. ‘Marabel’ and ‘Agata’ potatoes were represented by the negative portion of Principal Component 2, while ‘Almera’, ‘Agata’, and ‘Agria’ were located on the positive axis, highly correlated with hue angle variation which was statistically higher for these varieties. [Copyright &y& Elsevier]

Abstract: Selected fruits and vegetables were exposed to wounding, methyl jasmonate (MJ) or ethylene (ET) stress and effects on the phenylpropanoid metabolism were determined. Lettuce, cilantro, cabbage, green beans, apples, plums, peaches, table grapes, strawberries, bell peppers, asparagus, celery, carrots, radishes, potatoes, and jicama were evaluated for phenolic content and antioxidant capacity (AOX). The phenolic synthesis response to the stresses was tissue-dependent, including decreases, increases or no effects. The use of phytohormones enhanced the wound response on some crops, confirmed by an increase in phenylalanine ammonia lyase (PAL) activity and HPLC phenolic profiles. Several reasons could explain the phenolic accumulation, including the plant genetic machinery, the presence of a common signalling response and differences in phenolic synthesis and degradation kinetics. The synthesized phenolics increased the overall AOX (μg trolox/g FW) of the tissue. Furthermore, the specific AOX (μg trolox/mg phenolics) of the synthesized phenolic compounds was influenced by type of tissue and phytohormone used. [Copyright &y& Elsevier]

Abstract: In this study, the effects of long-term nitrogen deficiency (N 0.1mM for 4 months) on growth, phenolic content and activity of phenylalanine ammonia lyase (PAL; EC 4.3.1.5) were investigated in the leaves, inflorescences and roots of yarrow (Achillea collina Becker ex Rchb.) grown in hydroponics. The antioxidant capacity of methanol extracts was also evaluated. Nitrogen starvation decreased plant growth and the leaves’ total nitrogen, amino acids, proteins, chlorophylls and carotenoids contents indicating that the primary metabolism was severely limited by low nitrogen availability. The amount of total phenolics and the antioxidant capacity were higher in leaves and roots of nitrogen-starved compared to control plants. The most abundant phenolic acids identified in yarrow were 5-O-caffeoylquinic acid (chlorogenic acid), and 3,5 and 4,5-di-O-caffeoylquinic acids. Nitrogen starvation significantly increased the contents of all these compounds and the PAL activity in leaf and root tissues. Results suggest that hydroponics, with proper manipulation of nutritional factors, might be a suitable system for the production of compounds with health benefits, such as caffeic acid derivatives, in yarrow. [Copyright &y& Elsevier]

In this study it was shown that wounding in combination with hormone stresses synergistically enhanced the accumulation of bioactive phenolic compounds in carrot tissue. Whole carrots and carrots cut in slices, pie-cuts and shreds were exposed to 250μL/L methyl jasmonate and 1000μL/L ethylene treatments. Results indicated that hormone stress-induced phenolic compounds and phenylalanine ammonia lyase enzyme activity were dependent upon wounding intensity. The synthesized phenolics correlated to an increase in antioxidant capacity (AOX). In addition, both stresses affected the phenolic profiles. The different proportions of chlorogenic acid, dicaffeoylquinic acid and ferulic acid, for each stress and combinations, influenced the specific AOX of the phenolic profiles (the effectiveness of the phenolic compounds to neutralize free radicals). The bitter compound isocoumarin was mostly affected by the ethylene treatment compared to methyl jasmonate or wounding alone. Exposure to combined abiotic stresses could provide more AOX to regular diets and be a less expensive alternative to genetic modifications and breeding programs. [Copyright &y& Elsevier]