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Psammophilic halophytes are subjected in their natural habitats to the interactive effects of salinity and nutrient deficiencies. The aim of the present investigation was to check whether an optimal salt treatment enhances growth and antioxidant responses of the psammophilic obligate halophyte Sesuvium portulacastrum L. Seedlings were grown for 6 weeks on a nutrient medium (C), diluted 50 times (D), or diluted 50 times and added with 200 mM NaCl (DS). Nutrient deficiencies drastically reduced biomass production in both shoots and roots but did not induce a marked oxidative stress as shown by the ‘non-toxic’ levels of hydrogen peroxide (H2O2) and malondialdehyde (MDA). In roots, a marked decrease in catalase (CAT) activity seems to keep a certain level of H2O2 for stress signalling purposes. The detrimental effect on growth was slightly alleviated by the optimal salt concentration in DS treatment. H2O2 and MDA concentrations were higher in DS treatment than in D treatment, but they remained at ‘nontoxic’ levels. The responses of antioxidant enzymes showed the same trend in D and DS treatments but with different magnitudes. Taken together, these results showed that the beneficial effect of salinity on the responses of this psammophilic obligate halophyte to other stresses (i) is limited by the severity of those stresses and (ii) is not mainly based on antioxidant responses.

Since antiquity, the ubiquitous lactic acid bacteria (LAB) Enterococci, which are just as predominant in both human and animal intestinal commensal flora, have been used (and still are) as probiotics in food and feed production. Their qualities encounter several hurdles, particularly in terms of the array of virulence determinants, reflecting a notorious reputation that nearly prevents their use as probiotics. Additionally, representatives of the Enterococcus spp. genus showed intrinsic resistance to several antimicrobial agents, and flexibility to acquire resistance determinants encoded on a broad array of conjugative plasmids, transposons, and bacteriophages. The presence of such pathogenic aspects among some species represents a critical barrier compromising their use as probiotics in food. Thus, the genus neither has Generally Recognized as Safe (GRAS) status nor has it been included in the Qualified Presumption of Safety (QPS) list implying drastic legislation towards these microorganisms. To date, the knowledge of the virulence factors and the genetic structure of foodborne enterococcal strains is rather limited. Although enterococcal infections originating from food have never been reported, the consumption of food carrying virulence enterococci seems to be a risky path of transfer, and hence, it renders them poor choices as probiotics. Auspiciously, enterococcal virulence factors seem to be strain specific suggesting that clinical isolates carry much more determinants that food isolates. The latter remain widely susceptible to clinically relevant antibiotics and subsequently, have a lower potential for pathogenicity. In terms of the ideal enterococcal candidate, selected strains deemed for use in foods should not possess any virulence genes and should be susceptible to clinically relevant antibiotics. Overall, implementation of an appropriate risk/benefit analysis, in addition to the case-by-case assessment, the establishment of a strain’s innocuity, and consideration for relevant guidelines, legislation, and regulatory aspects surrounding functional food development seem to be the crucial elements for industries, health-staff and consumers to accept enterococci, like other LAB, as important candidates for useful and beneficial applications in food industry and food biotechnology. The present review aims at shedding light on the world of hurdles and limitations that hampers the Enterococcus spp. genus and its representatives from being used or proposed for use as probiotics. The future of enterococci use as probiotics and legislation in this field are also discussed.

Narcissus tazetta (Amaryllidaceae) is a medicinal plant, widely used for cut flowers and potted ornamental plant in Tunisia flora. The current study evaluated the phenolic composition and antioxidant properties of its flower extracts and investigated its potential protective activity against cadmium chloride (CdCl2)-induced hepatotoxicity in mice. Adult Swiss mice were exposed either to CdCl2 (0.16 mg/kg bw) or to Narcissus tazetta extract (100 or mg/kg bw) or to their combination. Cadmium chloride and Narcissus tazetta flower extracts were given by intraperitoneal injection and gavage respectively for eight consecutive days. Results indicated that ethanolic flower extracts contained high levels of total phenolic and flavonoid contents along with a strong total antioxidant and 2,2-Diphenyl-1-picrylhydrazyl free radical scavenging activities. High Performance Liquid Chromatography-Mass Spectrometry (HPLC-MS) analysis identified eight phenolic compounds, including rutin, Kaempferol glycosides and chlorogenic acids. The extract also exhibited marked hepato-protective effects against CdCl2 toxicity by reducing hepatic levels of malondialdehyde, advanced oxidation protein products, hydrogen peroxide, metallothioneins and DNA degradation. Additionally, co-administration of Narcissus tazetta flower extracts lowered the plasma activities of transaminases, gamma glutamyl transpeptidase and lactate dehydrogenase, and increased hepatic levels of reduced glutathione, non-protein thiols, vitamin C, and catalase activity. The hepatoprotective effects of the extract were demonstrated by histopathological improvement of liver disorders. The current study provided ethnopharmacological application of Narcissus tazetta flower extracts against CdCl2 induced oxidative stress, suggesting its chemoprevention role of its phenolic compounds as a natural antioxidant.

19 Páginas.-- 5 Figuras.-- 5 Tablas, The phytochemical composition of leaves, stems, pericarps and rhizomes ethanolic extracts of Asparagus acutifolius were characterized by HPLC-DAD-MS. A. acutifolius samples contain at least eleven simple phenolics, one flavonon, two flavonols and six steroidal saponins. The stem extracts showed the highest total phenolic acid and flavonoid contents, where cafeic acid and rutin were the main compounds. No flavonoids were detected in the leaf, pericarp or rhizome while caffeic acid and ferulic acid were the predominant. Steroidal saponins were detected in the different plant parts of A. acutifolius, and the highest contents were found in the rhizome extracts. The stem extracts exhibited the highest antioxidant activity against 2,2-diphenyl-1-picrylhydrazyl (DPPH) and ferric reducing antioxidant power (FRAP) and the highest 2,2-azino-bis (3 ethylbenzothiazoline-6-sulphonic acid) (ABTS) scavenging activity was found in the pericarp extracts. The rhizome and leaf extracts showed a potent cytotoxic activity against HCT-116 and HepG2 cell lines. Moreover, the pericarp and rhizome extracts revealed a moderate lipase inhibitory activity. The leaf and rhizome extracts were screened for their antimicrobial activity against human pathogenic isolates. The leaf extract exhibited a powerful inhibitory activity against all the bacteria and fungi tested., This research was funded by the Tunisian Ministry of Scientific Research and Technology and by the Ministerio de Ciencia e Innovación of Spain (AGL2017-82428-R).

Narcissus tazetta (Amaryllidaceae) is a medicinal plant widely used for cut flowers and potted ornamental plant in Tunisia flora. The current study evaluated the phenolic composition and antioxidant properties of its flower extracts and investigated its potential protective activity against cadmium chloride (CdCl

3 Figuras.-- 5 Tablas, Narcissus tazetta (Amaryllidaceae) is a medicinal plant widely used for cut flowers and potted ornamental plant in Tunisia flora. The current study evaluated the phenolic composition and antioxidant properties of its flower extracts and investigated its potential protective activity against cadmium chloride (CdCl)–induced hepatotoxicity in mice. Mice were divided into six groups of six each: group 1, serving as negative controls, received by intraperitoneal way only distilled water; group 2 received by intraperitoneal way CdCl (0.16 mg/kg bw); groups 3 and 4 received CdCl at the same dose of group 2 and 100 or 200 mg/kg bw of Narcissus tazetta flower extracts via oral route; groups 5 and 6, serving as positive controls, received only Narcissus tazetta flower extracts. Polyphenolic compounds of the extract were analyzed by colorimetric and high-performance liquid chromatography-mass spectrometry (HPLC-MS) methods. Total antioxidant activity and 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical scavenging potential of the extract were estimated using colorimetric method. Results indicated that ethanolic flower extract contained high levels of total phenolic and flavonoid along with a strong total antioxidant and DPPH free radical scavenging activities. HPLC-MS analysis identified eight phenolic compounds, including rutin, kaempferol glycosides, and chlorogenic acids. The extract also exhibited marked hepatoprotective effects against CdCl toxicity by reducing hepatic levels of malondialdehyde, advanced oxidation protein products, hydrogen peroxide, metallothioneins, and DNA degradation. Additionally, co-administration of Narcissus tazetta flower extracts lowered the plasma activities of transaminases, gamma glutamyl transpeptidase, and lactate dehydrogenase and increased hepatic levels of reduced glutathione, nonprotein thiols, vitamin C, and catalase activity. The hepatoprotective effects of the extract were demonstrated by histopathological improvement of liver disorders. The current study provided ethnopharmacological application of Narcissus tazetta flower extracts against CdCl-induced oxidative stress suggesting its chemoprevention role of its phenolic compounds as a natural antioxidant., This work received financial assistance from the Ministry of Higher Education and Scientific Research of Tunisia

CaCl2 effects on growth, photosynthesis, and Mg nutrition were investigated in safflower (Carthamus tinctorius L.) plants at low and optimal Mg availability. After seed germination on sand, obtained seedlings were grown under greenhouse conditions and subjected to 3 treatments for 4 weeks: control (C: 1.5 mM Mg), CaCl2 salinity (S: 40 mM CaCl2), and combined effects of CaCl2 salinity and Mg deficiency (DS: 0.1 mM Mg and 40 mM CaCl2). The application of 40 mM CaCl2 severely affected root, stem, young leaf, and old leaf growth. This was due to a combination of the three types of effects (osmotic, toxic, and nutritional). Indeed, in response to CaCl2 presence under both Mg-sufficient and deficient conditions, photosynthetic activity was reduced by stomatal closure to prevent cell dehydration. As a consequence, plant water status was not severely affected in S treatment and this osmotic effect disappeared under Mg-deficient conditions (DS treatment). Membrane integrity was slightly impaired in both S and DS treatments. Mg and Ca imbalances were also detected although plants exhibited adaptive responses to cope with Mg deficiency coupled or not with excessive Ca accumulation. Treated plants substantially increased Mg/Ca uptake selectivity, which allowed them to maintain Mg uptake efficiency unaffected. They also markedly increased their Mg use efficiency for chlorophyll synthesis. Nevertheless, amongst the three salt effects, nutritional imbalances seem to be the most harmful component. As a whole, the responses of the plant to the combined effects of CaCl2 application and Mg deficiency were dominated by salinity stress responses.

25 Páginas.-- 5 Tablas.-- 5 Figuras, The ability to control soil-borne pathogens in agriculture is highly conditioned by the restricted use of synthetic pesticides. Allelopathy, the antimicrobial activity of plant extracts, is a promising option against crop pathogens. Extracts from Lycium spp. such as L. barbarum, L. chinense and L. intricatum possess biological and therapeutic properties. Individual methanolic extracts from leaves and stems of the Mediterranean medicinal species L. europaeum collected in two locations of Tunisia were each evaluated in vitro against Verticillium dahliae (Vd), Sclerotinia sclerotiorum (Ss) and Harpophora maydis (Hm). The mycelial growth of the three fungi was significantly reduced by all the extracts at doses of 10 and 30 μl mL−1 (equivalent to 1 and 3 mg plant tissue mL−1). The sporulation of Hm was almost completely inhibited in all the amendments, but that of Vd was stimulated by one of the leaf extracts when 1 and 3 mg dried plant tissue mL−1 were used. Sclerotia of Ss were formed in a smaller number, their total weight increasing at extract doses equivalent to 1 mg plant tissue mL−1 and higher. In greenhouse, the pathogenicity of Hm was confirmed as early as 6 weeks after inoculation, since it caused significant decreases of weights in both roots and aboveground parts of maize. The detrimental effect of Hm on maize root weight in greenhouse was significantly counteracted by one of the leaf extracts added by watering. In total, 11 phenolic compounds were separated in the four extracts. The hydroxycinnamic acid family, including chlorogenic acid as a major compound, represented more than 50% of the total content in all the samples. Rutin was the most abundant flavonoid. The results of this work show the detrimental effect of L. europaeum extracts against the soil-borne pathogens Hm, Ss and Vd, and highlight their potential in crop protection if adequately developed into final products and used in combination with other tools., This research was partially supported by grants AGL2010–17909 (Ministerio de Economía y Competitividad, Spain) and P12-AGR1281 (Andalusian Government, Spain) and the European Regional Development Fund (ERDF). The stay of R. Tej was granted by the Ministry of Higher Education and Scientific Research in Tunisia.

The agriculture industry is frequently affected by various abiotic stresses limiting plant productivity. To decrease the negative effect of salinity and improve growth performance, some strategies have been used, such as exogenous application of plant growth regulators (i.e. gibberellic acid, GA 3 ), or arbuscular mycorrhizal fungi (AMF) inoculation. To gain insights about the cross-talk effect of exogenous GA 3 application and AMF inoculation on growth under salinity conditions, tomato plants ( Solanum lycopersicum, cv. TT-115) were inoculated or not with the AMF Rhizophagus irregularis and exposed to different treatments during two weeks: 0 M GA 3 + 0 mM NaCl, 10 −6 M GA 3 + 0 mM NaCl, 0 M GA 3 + 100 mM NaCl and 10 −6 M GA 3 + 100 mM NaCl. Results have revealed that AMF inoculation or GA 3 application alone, but especially their interaction, resulted in growth improvement under salinity conditions. The growth improvement observed in AMF-inoculated tomato plants under salinity conditions was mainly associated to ionic factors (higher K concentration and K/Na ratio) while the alleviating effect of GA 3 application and its interaction with AMF appear to be due to changes in the hormonal balance. Foliar GA 3 application was found to increase the active gibberellins (GAs), resulting in a positive correlation between GA 3 and the growth-related parameters. Furthermore, cytokinins, indoleacetic acid and abscisic acid concentrations increased in AMF inoculated or GA 3 treated plants but, notably, in AMF plants treated with GA 3 , which showed improved growth under salinity conditions. This suggests that there is an interactive positive effect between GAs and AMF which alleviates growth impairment under salinity conditions by modifying the hormonal balance of the plant.

The purpose of the present investigation is to assess, for the first time, the antidiabetic, antihyperlipidemic and antioxidant activities of Lycium europaeum extract in alloxan-induced diabetic rats. Diabetes was induced in adult male Wistar rats via a single subcutaneous alloxan injection (120 mg/kg). Lycium europaeum aqueous extract was orally administered at a dose of 20 mg/kg for 28 consecutive days. Serum concentrations of total cholesterol (TC), low-density lipoprotein cholesterol (LDL-C), high-density lipoprotein cholesterol (HDL-C) and triglycerides (TG) were assayed at the end of the experimental period in all investigated groups. Antioxidant enzymes such as glutathione peroxidase (GPx), catalase (CAT) and superoxide dismutase (SOD) were sought in the serum and pancreas. Lycium europaeum extract significantly increased HDL-C and reduced blood glucose, TC, LDL-C and TG as compared to the alloxan-control group. Lycium europaeum extract was also efficient in reducing oxidative stress in diabetic rats by increasing SOD, CAT and GPx activities both in the pancreas and the plasma of the animals. Moreover, Lycium europaeum extract contained considerable levels of polyphenols and flavonoids. It also exhibited an important antioxidant capacity and a remarkable ability to quench DPPH radicals and reduce irons. The obtained results highlight potentially relevant health beneficial effects of Lycium europaeum extract, reversing hyperglycemic, hyperlipidemic and oxidative stress effects in rats with alloxan-induced diabetes. Therefore, it may be considered as a promising alternative or complementary agent to diabetes treatment.

Black nightshade (Solanum nigrum, S. nigrum L.) and red nightshade ( Solanum villosum, S. villosum Mill.) are medicinal plants from the Solanaceae family that synthesize glycoalkaloids and other secondary metabolites. To recognize the potential insecticide activity of these compounds, leaf extracts (containing glycoalkaloid and methanol fractions) were tested for enzyme inhibition, antifeedant activity and toxicity. For in-vitro glutathione S-transferase (GST) inhibition activity, we used insecticide-resistant Colorado potato beetle, Leptinotarsa decemlineata ( L. decemlineata; Say) midgut and fat-body homogenate. In-vivo toxicity and the antifeedant activity were performed using larval bioassays. The methanol extracts had greater GST inhibitory activity compared to the glycoalkaloids, as well as greater 2nd instar larvae mortality and antifeedant activity. Furthermore, the green leaf volatile compound, cis-hex-3-enyl acetate, at the concentration of 5 ppm, caused 50% mortality of 2nd instar larvae. Our findings suggest the potential usefulness of S. nigrum and S. villosum extracts to control L. decemlineata.

The agriculture industry is frequently affected by various abiotic stresses limiting plant productivity. To decrease the negative effect of salinity and improve growth performance, some strategies have been used, such as exogenous application of plant growth regulators (i.e. gibberellic acid, GA

5 Tablas.-- 3 Figuras, The ethanolic extracts from the leaves, pericarps and rhizomes of Asparagus albus L. were investigated for their phytochemical composition, antioxidant (DPPH and FRAP assays), anti-microbial against human pathogenic isolates and cytotoxic (human colon carcinoma HCT-116 cells) activities. The highest flavonoid content was obtained in the leaf extract followed by the pericarp but there were no flavonoids detected in the rhizome. However, the rhizome had a high concentration of saponins. Flavonoid and saponin profiles were similar to those previously described for the triguero Huetor Tajar asparagus landrace. It was found that the pericarp ethanolic extract exhibited higher antioxidant activity than rhizome and leaf extracts. Moreover, the rhizome possessed more evident cytotoxic activity against HCT-116 cells in comparison to leaf and pericarp. All extracts showed varying degrees of antimicrobial activity against most of the human pathogenic isolates. In addition, the leaves showed more powerful inhibitory activities against the maximum number of bacteria and all the fungai isolated and the highest activity was in the pericarp extract against multidrug resistant Pseudomonas aeruginosa (MDR) and Erythromycin resistant Streptococcus agalactiae (ER) with an inhibition zone of 21 mm and 19 mm, respectively. The results show that A. albus could be a new crop with pharmaceutical interest because its richness in bioactive compounds provides considerable benefits for human health., This work was supported by the Tunisian Ministry of Scientific Research and Technology and by the Ministerio de Ciencia e Innovación of Spain (AGL2011-29632). The authors are enormously grateful to Dr. Ilhem Boutiba Ben Boubaker (Antibiotic resistance laboratory, Faculty of Medicine of Tunisia) and Dr. Saadia Gargouri (Department of parasitology, Military Hospital of Tunis) for their assistance during the antimicrobial analysis and to Dr. Smaoui Abderrazek for botanical identification of the plants.

Black nightshade (Solanum nigrum, S. nigrum L.) and red nightshade ( Solanum villosum, S. villosum Mill.) are medicinal plants from the Solanaceae family that synthesize glycoalkaloids and other secondary metabolites. To recognize the potential insecticide activity of these compounds, leaf extracts (containing glycoalkaloid and methanol fractions) were tested for enzyme inhibition, antifeedant activity and toxicity. For in-vitro glutathione S-transferase (GST) inhibition activity, we used insecticide-resistant Colorado potato beetle, Leptinotarsa decemlineata ( L. decemlineata; Say) midgut and fat-body homogenate. In-vivo toxicity and the antifeedant activity were performed using larval bioassays. The methanol extracts had greater GST inhibitory activity compared to the glycoalkaloids, as well as greater 2nd instar larvae mortality and antifeedant activity. Furthermore, the green leaf volatile compound, cis-hex-3-enyl acetate, at the concentration of 5 ppm, caused 50% mortality of 2nd instar larvae. Our findings suggest the potential usefulness of S. nigrum and S. villosum extracts to control L. decemlineata.

Salinity effects on growth and essential oil composition of Tunisian safflower (Carthamus tinctorius) shoots grown in hydroponic medium were investigated. Plants treated with 25 mM NaCl showed remarkable morphological modifications and decrease in shoot dry matter. Under 50 and 75 mM NaCl, plants showed a withering and a drastic reduction in dry matter (50% and 70%, respectively). Under NaCl 25 mM, essential oil yield increased significantly (p

This study investigates the polyphenol content of Diplotaxis simplex extract and the biological activities of the main organ. The analysed extracts showed that polyphenol contents varied considerably as a function of organs. Furthermore, novel biological activities of this species were assessed. Flower extracts exhibit a potent in vitro antioxidant capacity using oxygen radical absorbance capacity and displayed a strong anti-inflammatory activity, inhibiting nitric oxide release, by 79.3% at 160 μg/mL. Our findings suggested that the Diplotaxis flower is a valuable source of antioxidants and anti-inflammatory agents.

In the present work, separate and combined effects of excessive potassium and magnesium deficiency on safflower (Carthamus tinctorius) were studied. Four treatments were considered: C (control treatment: complete medium containing 1.5 mM Mg), +KCl (excessive potassium treatment: complete medium added with 60 mM KCl), −Mg (Mg-deficient treatment: containing 0.1 mM Mg), and DS (double stress treatment: Mg-deficient medium (0.1 mM Mg) added with 60 mM KCl. Excessive potassium effect on plant growth was more pronounced than that of Mg deficiency. The two stresses impaired differently plant organs; KCl application affected more roots than shoots, whereas Mg deficiency reduced only leaf biomass. Gas exchange and pigment concentrations and patterns were severely impaired by KCl and mainly by interactive effects of the two stresses. This led to obvious lipid peroxidation and electrolyte leakage. Mg deficiency did not induce lipid peroxidation and electrolyte leakage, but as applied with excessive potassium, it doubled the effect of the latter. Mineral analyses showed that major cation nutrition was disturbed by KCl and combined stresses and at a lower level by magnesium deficiency. Plants did not show an enhanced selectivity of Mg and Ca over K but they improved their use efficiencies.

This study examined the influence of salt levels on antioxidant activity and content of carotenoids and anthocyanins of the A. hortensis leaves using two varieties: green orach (var. purpurea ) and red orach (var. rubra). Seeds of Atriplex were exposed to 0, 90, 180 and 260 mM NaCl for 3 months and seeds were sown in an earthen pot. Overall levels of ascorbate peroxidase (APX) and glutathione reductase (GR) activity were significantly elevated. Salt stress caused a significant decline in tissue concentrations of catalase (CAT) and superoxide dismutase (SOD). However, 90 mM NaCl did not modify these parameters, which remains similar to control values. Activities of APX and CAT were increase whether the shoots of A. hortensis var. purpurea were grown in the presence of 180 mM NaCl. Thus although some indications of oxidative stress accompany exposure of this salt-tolerant Atriplex varieties to salinity, mechanisms appear to exist within its shoot tissue to permit the tolerance of such oxidative stress. High salt concentration in the culture medium provokes oxidative damage in Atriplex leaves and induces a general increase in antioxidant enzyme activity. In particular, NaCl toxicity decreased content of carotenoids. It also decreased the concentration of anthocyanin pigments in leaves of Atriplex. This work therefore provides a starting point towards a better understanding of the role of antioxidant enzyme in the plant response against salt stress.

In the present work, we investigated the effect of salt stress on the distribution of safflower (Carthamus tinctorius L.) antioxidant system in relation to leaf age. The study was carried out under growth chamber conditions using seedlings of three cultivars which were subjected to 0 and 50 mM NaCl for 3 weeks. Leaf growth, water content, lipid peroxidation, and phenolic compound (total polyphenols, total flavonoids, and proanthocyanidins) concentration were measured at two leaf stages (young and old leaves). Leaf growth was affected by salinity only in Kairouan cultivar that also showed a significant decrease in old leaf water content. By contrast, Gabes and Tazarka cultivars maintained their old leaf water content constant and showed a reduction in that of young leaves. This could be attributed to a higher aptitude of the latter two cultivars to use absorbed sodium and chloride for osmotic adjustment in old leaves, keeping potassium for specific functions. Salt-induced lipid peroxidation was observed only in old leaves, whereas the accumulation of the major phenolic compounds under saline conditions was higher in young leaves, except in Gabes cultivar where no significant difference was found between the two leaf stages. A significant variability was also found between the three cultivars. The better behavior of salt-challenged leaves of Gabes and Tazarka cultivars compared to that of Kairouan cultivar may be related to their higher water content and the accumulation of polyphenols, in particular flavonoids that were shown to be efficiently involved in the restriction of salt-induced oxidative damages.

In this study, we set out to investigate the effect of sodium chloride (NaCl) on carotenoid and flavonoid production by the black nightshade (Solanum nigrum L.). The study was carried out under green chamber conditions using seedlings subjected to 0, 50, 100 and 150 mM NaCl for 3 weeks. The negative effect of NaCl on dry biomass production of roots and leaves were accompanied by a significant restriction in K+, Ca2+ and Mg2+ ion uptake and by an increase in Na+ ion concentrations, the effects of which were most pronounced at the highest NaCl level. Salt stress also induced oxidative stress, according to the amplified levels of thiobarbituric acid reactive substances and relative ion leakage ratio. Expression of some related carotenoid (phytoene synthase 2 and β-lycopene cyclase) and flavonoids genes (phenylalanine ammonialyase, chalcone synthase and flavonol synthase) were induced by NaCl, followed enhanced production of β-carotene, lutein, and quercetin 3-β-d-glucoside. At the highest NaCl level (150 mM NaCl), quercetin 3-β-d-glucoside synthesis came at the expense of reduced β-carotene and lutein, while salt stress treatment affected leaf antioxidant activities to a great extent relative to the control. Our data suggest that the potential antioxidant properties of carotenoids and flavonoids and their related key genes may be efficiently involved in the restriction of salt-induced oxidative damages.

Safflower (Carthamus tinctorius L.) leaves are a good source of natural antioxidants, but their content is highly related to the plant response to NaCl constraint; therefore, optimizing culture conditions is required to improve leaf antioxidant accumulation while maintaining acceptable biomass production under stressful conditions. Leaves from plants grown at (0, 25, 50, and 75 mM NaCl) for three treatment durations (7, 15, and 30 days) were studied. NaCl concentrations and treatment durations for optimal biomass and biomolecules production were concluded. After 30 days of treatment, 25 mM NaCl enhanced total AsA leaf accumulation, while glutathione, soluble protein accumulation as well as SOD and GR activities were promoted at 75 mM NaCl. Non-significant changes were found for MDHAR and DHAR activity, added to, a very low level of reduced AsA, suggesting that ascorbate recycling was not an efficient system in safflower leaves under salinity. Our study demonstrates that C. tinctorius tolerates NaCl stress due to the complementary roles of powerful antioxidant molecules, such as ascorbate (for short-term treatments), glutathione (for long-term treatments), and increased SOD and GR activities.

This study examined the influence of salt treatment on the growth parameters (fresh and dry weights), the mineral content (K+ and Na+), total lipid contents, fatty acid composition, yields and chemical composition of the essential oil of safflower (Carthamus tinctorius L.) grown in hydroponics for 2 weeks. Results showed that the application of 50 mM NaCl reduced the fresh weight of aerial parts (shoots and leaves) while it enhanced those of the roots. The reduction of dry weight was found to be more pronounced in the aerial parts. Salt treatment increased markedly the concentrations of Na+ in both plant parts while it reduced those of K+ which resulted in a sharp reduction of K+/Na+ ratio. In response to salt treatment, total lipids contents decreased in both plant parts and great qualitative changes in the fatty acids profiles were observed. Whatever the plant parts analysed, a redirection of the lipidic metabolism towards synthesis of unsaturated fatty acids as revealed by the increase of double bond index and linoleic desaturation ratio was pointed out. The increased unsaturation index was found to be more important in roots than in aerial parts. Such treatment also reduced the essential oil yields and induced marked quantitative changes in the chemical composition of the essential oils from both plant parts. Of all the identified components, oxygenated components display a prominent salt-induced synthesis and/or accumulation in both roots and aerial parts.

The study of NaCl effects on wheat and triticale showed an increase in root biomass from the lowest dose (50 mM) in the two cereals and maintenance of shoot growth even at the highest concentration (200 mM). However, triticale shoot growth was decreased by 25% at 200 mM NaCl. Wheat absorbed and exported more Na+ ions to its shoots than triticale. The latter accumulated the majority of the absorbed sodium within its roots. In addition, triticale seems to be more selective towards K+ ions since it limited Na+ uptake and transport to shoots and ensured better K+ nutrition. The measurements of root respiration intensity in seedlings grown under saline (100 mM NaCl) and non saline (0 mM NaCl) conditions showed that in salt—treated wheat plants, respiration displayed no change, whereas in those of triticale, it was enhanced by 27% as compared to the control. This stimulation could be related to K/Na selectivity.

Seedlings of two Tunisian Carthamus tinctorius L. provenances (Kairouan and Tazarka) differing in salt sensitivity were hydroponically grown at 0 and 50 mM NaCl over 21 days. Leaves of Kairouan (salt-sensitive) showed a 48% restriction in their growth at 50 mM NaCl although they accumulated less sodium than those of Tazarka (less salt-sensitive) that maintained an unchanged growth. Salt treatment induced oxidative stress in C. tinctorius and the effect was more pronounced in the leaves of the more salt sensitive provenance, Kairouan. Both provenances exhibited a stimulation of antioxidant enzyme activities with higher catalase (CAT) and superoxide dismutase (SOD) activities in Tazarka and higher peroxidase (POD) activity in Kairouan. But, it seems that antioxidant activities were more correlated with polyphenol content. Actually, leaves of Tazarka experienced higher polyphenol and antioxidant activity than Kairouan at 50 mM NaCl. Hence, moderate salinity (3 g NaCl L−1) enhanced bioactive molecule yield in the less salt sensitive provenance, Tazarka. In addition, C. tinctorius was found rich in ascorbic acid, but the moderate salt stress enhanced its production only in the sensitive provenance.

We investigated the relative contributions of the environment and development stage on total polyphenols, flavonoids and condensed tannins contents, as well as 1,1-diphenyl-2-picrylhydrazyl (DPPH) and superoxide scavenging activities in four Tunisian Mentha pulegium. Shoot total phenolics and antioxidant capacities were significantly dependent on environment, development stage and their interaction. Environment effects were considerably larger than development stage effects for total phenolics, flavonoids, DPPH and superoxide scavenging capacities, whereas development stage was much stronger than environment for tannin content and, although small, interaction effects of the two factors (environment and development stage) were significant for all antioxidant properties analyzed. The highestantioxidant activities were related to high phenolic contents. Three behaviors were revealed; the best antioxidant capacities in Soliman at floral bud stage, followed by Takelsa and the lowest potentialities (Bouarada and Jdeida). These findings indicate that antioxidant properties of M. pulegium were respectively influenced by environment, development stage and their interaction. PRACTICAL APPLICATION Mentha pulegium L. belonging to the Lamiaceae family, which is a highly advanced and homogeneous family, is largely used in food preparation, perfumery, pharmaceutical products and as an insect repellent. In traditional medicine, M. pulegium essential oil is used for digestive, liver and gallbladder disorders, for gout colds and increased micturition and externally for skin diseases (Gruenwald et al. 1998). M. pulegium is a folkloric medicinal plant with interesting shoot antioxidant properties. According to our results, high antioxidant properties of the leaves of M. pulegium might be beneficial to the antioxidant activity.

The aim of the present work was to study salt effect on the yield and composition of shoot essential oil (EO) and the structures responsible for its biosynthesis in Mentha pulegium L. Shoot EO was extracted by hydrodistillation and composition was determined by GC–MS method. Apical and basal leaves were taken for microscopy analyses; small fresh samples were observed directly without fixation or metallisation with environmental scanning electron microscope (ESEM) and stereomicroscope (SM). Fresh separate epidermis was used for light microscopy (LM). Salt stress enhanced EO yield by about 2.75 times and affected the percentage of menthone, which is the major compound (∼51%), increasing that of pulegone. Menthone, pulegone, and neomenthol constituting the monoterpene class were found to be the principal components. The anatomical study showed three types of trichomes: (i) non-glandular, multicellular, simple hairs; (ii) small, capitate glandular trichomes; (iii) and peltate glandular trichomes. In control plants, the density and size of trichomes varied with leaf side (abaxial or adaxial) and developmental stage. Salt stress results in significant modifications affecting trichome distribution and size on both sides.

Mentha pulegium L. is a medicinal and aromatic plant belonging to the Labiatae family present in the humid to the arid bioclimatic regions of Tunisia. We studied the effect of different salt concentrations on plant growth, mineral composition and antioxidant responses. Physiological and biochemical parameters were assessed in the plant organs after 2 weeks of salt treatment with 25, 50, 75 and 100 mM NaCl. Results showed that, growth was reduced even by 25 mM, and salt effect was more pronounced in shoots (leaves and stems) than in roots. This growth decrease was accompanied by a restriction in tissue hydration and K+ uptake, as well as an increase in Na+ levels in all organs. Considering the response of antioxidant enzymes to salt, leaves and roots reacted differently to saline conditions. Leaf and root guaiacol peroxidase activity showed an increase by different concentration of NaCl, but superoxide dismutase activity in the same organs showed a slight modification in NaCl-treated leaves and roots. Moreover, polyphenol contents and antioxidant activity were analysed in M. pulegium leaves and roots under salt constraint. The analysis showed an increase of total polyphenol content (2.41–8.17 mg gallic acid equivalent g−1 dry weight) in leaves. However, methanol extract of leaves at 100 mM NaCl displayed the highest DPPH· scavenging ability with the lowest IC50 value (0.27 μg ml−1) in comparison with control which exhibited IC50 equal to 0.79 μg ml−1.

Morpho-physiological and biochemical responses of Arabidopsis thaliana (accession N1438) to bicarbonate-induced iron deficiency were investigated. Plants were grown in cabinet under controlled conditions, in a nutrient solution containing 5 μM Fe, added or not with 10 mM NaHCO3. After 30 days, bicarbonate-treated plants displayed significantly lower biomass, leaf number and leaf surface area as compared to control plants, and slight yellowing of their younger leaves was observed. Potassium (K+) content was not modified by bicarbonate treatment in roots, whereas it was significantly diminished in shoots. Their content in ferrous iron (Fe2+) and in leaf total chlorophylls was noticeably lower than in control plants. Root Fe(III)-chelate reductase and phosphoenolpyruvate carboxylase (PEPC) activities were significantly enhanced, but leaf ribulose 1.5-bisphosphate carboxylase (Rubisco) activity was decreased.

Polyphenols are bioactive molecules exhibiting a lot of scientific attention due to their multiple biological activities. This study compared phenolic contents and antioxidant activity in Cynara cardunculus L. organs and focus on leaf phenolic compounds identification by RP-HPLC and their antibacterial activity. The analyzed organs exhibited different total polyphenol contents (7-14.8 mg GAE g(-1) DW). Leaf and seed phenolic contents were similar and two times higher than those in flowers. The same tendency was observed for the amount of flavonoids and tannins. However, seed extracts displayed the highest DPPH. scavenging ability with the lowest IC50 value (23 microg ml(-1)), followed by leaves and flowers (over 50 microg ml(-1)). In contrast, leaves showed the highest capacity to quench superoxide (IC50: 1 microg ml(-1)) as compared to seeds (6 microg ml(-1)). In addition, cardoon leaves were efficient to inhibit growth of pathogenic bacteria mainly against Staphylococcus aureus and Escherichia coli. The identification of phenolic compounds from leaves revealed that syringic and trans-cinnamic acids were the major molecules.

The present research work describes the effects of 2,4-dichlorophenoxyacetic acid (2,4-d)/Benzylaminopurine (BAP) ratio on callus induction, total phenolic and ascorbic acid production, and antioxidant activities in leaf-derived calli of Crataegus azarolus (hawthorn). The supplementation of 1.0 mg/L 2,4-d and 1.0 mg/L BAP to MS medium was found to be the most efficient for callus induction (as percentage and fresh weigh). The results of biochemical analysis showed that the highest total phenolic contents were obtained in callus cultured on MS medium supplemented with 2.0 mg/L 2,4-d and 1.0 mg/L BAP (52 ± 0.56 mg GAE/g DM) and were significantly lower than those of intact leaves (76 ± 1.72 mg GAE/g DM). However, the highest ascorbic acid contents were found in callus cultured on MS medium supplemented with 1.0 mg/L 2,4-d and 0.5 mg/L BAP (0.96 ± 0.13 mg AAE/g DM) and these amounts were statistically similar to those found in leaf tissues (0.74 ± 0.07 mg AAE/g DM). Antioxidant activities of callus extracts were determined using two TEAC assays and results showed that extract of callus cultured on MS medium supplemented with 2.0 mg/L 2,4-d and 1.0 mg/L BAP have the greatest antiradical activities against DPPH (124 ± 2.92 mg TE/g DM) and ABTS (0.19 ± 0.02 mg TE/g DM) compared to the leaves of field-grown plant. Thus, the use of high level of 2,4-d over BAP can be suitable to enhance the quality more than the quantity of bioactive compounds in leaf callus culture of hawthorn.

This study investigates the polyphenol content of Diplotaxis simplex extract and the biological activities of the main organ. The analysed extracts showed that polyphenol contents varied considerably as a function of organs. Furthermore, novel biological activities of this species were assessed. Flower extracts exhibit a potent in vitro antioxidant capacity using oxygen radical absorbance capacity and displayed a strong anti-inflammatory activity, inhibiting nitric oxide release, by 79.3% at 160 μg/mL. Our findings suggested that the Diplotaxis flower is a valuable source of antioxidants and anti-inflammatory agents.

The antioxidant and hepatoprotective activities of hot aqueous extract from Asparagus albus (A. albus) leaf against CCl4-induced liver damage in rats were investigated. The total phenolic, flavonoid, and condensed tannin contents of hot aqueous extract from A. albus leaf were determined. The antioxidant activity of hot aqueous extract from A. albus leaf was evaluated using the antioxidant capacity, DPPH free radical-scavenging ability and reducing power assays. Different polyphenolic compounds, namely gallic acid, vanillic acid, 3,4 dimethoxybenzoic acid, catechin, rutin, and quercetin were identified. Oral administration of hot aqueous extract from A. albus leaf to male Wistar, intoxicated with CCl4, demonstrated a significant protective effect by lowering the levels of hepatic marker enzymes (aspartate and lactate transaminases) and by improving the histological architecture of the rat liver. The hot aqueous extract from A. albus leaf attenuated oxidative stress by restoring the activities of superoxide dismutase, catalase, and glutathione peroxidase. This study demonstrated that the hot aqueous extract from A. albus leaf protects rat liver from CCl4-induced injury and suggests a potential therapeutic use for A. albus plant. Practical applications The hepatoprotective effects of plant extracts are mainly related to their richness in phenolic compounds. Phenolic compounds are secondary metabolites widely found in plants, mostly represented by phenolic acids and flavonoids. The growing interest in these bioactive antioxidant components is principally due to their antioxidant potential and the association between their consumption and the prevention of some diseases. In this study, a remarkable hepatoprotective effect of the hot aqueous leaf extract obtained from Asparagus albus was detected against CCl4-induced liver injury in rat and its mechanism was related, at least in part, to its free radical scavenging and antioxidant activity on account of the presence of polyphenols.

International audience; Diplotaxis species are edible and medicinal plants. This study investigates phenolic contents and biological activities in stems, leaves, and flowers of Diplotaxis harra and Diplotaxis simplex. Flowers exhibited the highest polyphenol content and D. harra was significantly more phenol-rich than D. simplex. Similarly, the highest antioxidant activities were found in D. harra flowers. Fractionation of D. harra extract revealed that 60% MeOH fraction showed the best antioxidant activities. Indeed, flower fractions were assayed for their activity against human pathogenic bacteria and the inhibitory percentages reached 100%. As regards fraction polarity, 60% and 80% MeOH fractions were the most active ones. Moreover, HPLC analysis showed that the main phenolic compound was cafeic acid for the two species, whereas p-Coumaric and 3,4-dimethoxybenzoic acids were identified only in D. simplex and sinapic acid was exclusive to D. harra. Overall, our findings indicate that Diplotaxis flowers could be used as a potent source of natural antioxidants and antibiotics

In the present investigation, we studied uptake and management of the major cations in the xerohalophyte, Tecticornia indica (Willd.) subsp. indica as subjected to salinity. Plants were grown under greenhouse conditions at various salinity levels (0, 100, 200 and 400 mM NaCl) over 110 days. At harvest, they were separated into shoots and roots then analyzed for water contents, dry weights (DW), and Na+, K+, Ca²+, and Mg²+ contents. Plants showed a growth optimum at 200 mM NaCl and much better tissue hydration under saline than non-saline conditions. At this salt concentration (200 mM NaCl), shoot Na+ content reached its highest value (7.9 mmol · g-⁻¹ DW). In spite of such stressful conditions, salt-treated plants maintained adequate K+, Ca²+, and Mg²+ status even under severe saline conditions. This was mainly due to their aptitude to selectively acquire these essential cations and efficiently use them for biomass production.

Physiological responses of Arabidopsis thaliana to the interaction of iron deficiency and nitrogen form were studied using plants grown in hydroponics. Thirty-three-day-old seedlings were submitted to four treatments for 7 days: NO 3 + 5 microM Fe; NO 3 + 0.1 microM Fe; NH 4 + 5 microM Fe and NH 4 + 0.1 microM Fe. Leaf growth and chlorophyll content were highest in NO 3 -fed, Fe sufficient plants, but were strongly diminished by Fe deficiency under nitric nutrition, and by ammoniacal nutrition independently of Fe regime. However, the leaves of NH 4 -fed plants presented a higher Fe content than those of Fe sufficient, NO 3 -fed plants. Thus, leaf chlorosis of NH 4 -fed in plant did not depend on Fe availability, and seemed to be due to another factor. Root acidification capacity and Fe-chelate reductase (FCR) activity were also dependent on N form. The medium was acidified under ammoniacal regime and alkalinized under nitric regime regardless of Fe level. FCR activity stimulation in response to Fe deficiency was observed only in NO 3- fed plants. In addition, both N form and Fe level induced antioxidant responses in rosette leaves. Ammoniacal regime increased both peroxidase expression and anthocyanin accumulation, whereas Fe deficiency enhanced superoxide dismutase expression.

International audience; Arabidopsis thaliana is a glycophyte capable to tolerate mild salinity. Although salt sensitivity of this species, a variability of this characteristic was revealed between different ecotypes. This study presents the physiological and molecular characteristics of salt response of two ecotypes, NOK2 and Columbia (Col). Seedlings were cultivated in hydroponics in the presence of 0 or 50 mM NaCl during 25 days. Rosette leaf samples were collected after 19, 22, and 25 days for determination of physiological parameters, and after 18 days for study of DNA polymorphism. Salt treatment decreased rosette dry matter, leaf number, leaf hydration, and leaf surface area. All these effects were significantly more visible in Col than in NOK2. Moreover, the NOK2 leaves accumulated less Na+ and more K+ than those of Col. DNA polymorphism between the two ecotypes was analyzed with codominant molecular markers based on PCR amplification, namely, microsatellites, cleaved amplified polymorphism sequence (CAPS), and single nucleotide polymorphism markers (SNP). Among the 35 tested markers, 17 showed a clear polymorphism and were distributed on the five Arabidopsis chromosomes ending with a genetic map construction. These results could play an important role in the future establishment of cartography of candidate gene controlling the K+/Na+ selectivity of ion transport in leaves, a component of plant salt tolerance.