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Thymelaea microphylla is an edible and medicinal species that exhibits high antioxidant activity and phenolic content. Moreover, four fractions (hexane, dichloromethane, methanol and water) were tested towards their ex-vivo antioxidant, anticancer, anti-inflammatory and antiviral effects. Dichloromethane fraction had marked protection against cell oxidative stress (IC50 = 1.5 µg/mL). Hexane, Dichloromethane and Methanol fractions exhibited prominent anti-proliferative activities against cancer cells especially A-549 cells, with very low IC50 values of 0.13, 0.018 and 0.5 µg/mL, respectively (50, 101 and 14 higher than Etoposide). Moreover, the three fractions showed no cytotoxicity on normal fibroblast WS-1. DCM exhibited high anti-inflammatory activity in RAW 264.7 cells. Theses fractions were also tested on herpes (HSV-1). MeOH fraction was the most active acting both directly on the virus and on its adsorption. Phenolics, terpenoids and saponins were the major classes. These findings demonstrate that T. microphylla is a very promising source of selective anticancer molecules.

Depuis la nuit des temps, les plantes ont été la source principale de molécules bioactives, tels les composés phénoliques, capables de remédier à diverses maladies. Cependant, le contenu et l’activité des polyphénols dépendent d’un certain nombre de facteurs intrinsèques et extrinsèques. Dans le but d’optimiser les procédés d’obtention des principes actifs de la verveine (Verbena officinalis), les effets de la provenance de la plante, du solvant et de la méthode d’extraction ont été évalués. Ainsi, la partie aérienne de V. officinalis a été collectée dans deux régions différentes de la Tunisie (Bizerte et Ain Draham). L’extraction a été réalisée par macération, décoction et par l’appareil de Soxhlet tantôt avec de l’eau tantôt avec de l’éthanol pur. Une variabilité significative des teneurs en composés phénoliques ainsi que des capacités antioxydantes et antimicrobiennes des extraits a été observée en fonction des facteurs étudiés. De manière générale, les extraits éthanoliques sont plus riches en composés phénoliques et présentent des activités antioxydantes plus fortes que les extraits aqueux. Cependant, vis-à-vis de différentes souches pathogènes, les extraits aqueux sont souvent au moins aussi puissants que les extraits éthanoliques pour inhiber la croissance bactérienne in vitro. De plus des différences notables sont observées selon que V. officinalis provient de la région de Bizerte ou d’Ain Draham. Ces résultats montrent que la prise en compte de plusieurs paramètres est nécessaire pour optimiser l’efficacité des procédures d’extraction des molécules bioactives de V. officinalis.

This study aims to calculate the optimal formula combining Syzygium aromaticum, Cinnamomum zeylanicum, Myrtus communis, and Lavandula stoechas essential oils to enhance their anti-Staphylococcus aureus effects. Firstly, a chemical analysis of essential oils (EOs) was assessed. Secondly, their antibacterial activities were screened against several bacterial strains with a special emphasis on S. aureus one. Finally, a specific mixture design plan was elaborated to determine the combination presenting the highest protection against S. aureus. Thus, the complex simplex-centroid mixture design was adopted to build polynomial models detailing the relationship between the anti-S. aureus activity and the proportion of each essential oil. Obtained results indicated compositional variabilities between studied samples. Indeed, the major compounds were camphor (35%), α-pinene (75%), cinnamaldehyde (89%) and eugenol (75%) for lavender, myrtle, cinnamon, and clove EOs, respectively. Additionally, the antibacterial activity test illustrated that all studied EOs were potent antimicrobial agents especially cinnamon and clove ones (from 15 to 39 mm inhibition zone). The search for the most effective combination for milk preservation against S. aureus suggested that a mixture of 58.8% cinnamon, 34.4% clove, and 6.8% lavender presents the optimal efficiency (reduction to 1 ± 0.1 × 106 CFU.ml−1). Thereby, this formula could be considered as a potential alternative for food safety against S. aureus contamination, particularly in milk and dairy industries.

Plants have been seen to possess the potential to be excellent biological matrices to serve as a basis for investigating the presence of promising therapeutic agents for cancer treatment. Several successful anti-cancer medicines - or their analogues - nowadays in use are plant derived and many more are under clinical trials. Under current circumstances, the purpose of this work was to test aqueous and ethanolic extracts of five aromatic and medicinal plants from arid zones on some tumor cell lines. These plants, Cymbopogon schoenanthus (L.) Spreng, Crithmum maritimum (L.) Spreng, Hammada scoparia (Pomel) Iljin, Retama raetam (Forssk.) and Zizyphus lotus (L.) Desf., widely used in Tunisian ethnomedicine, were assessed for their phenolic compounds, antioxidants and anticancer activities in aqueous and ethanol extracts. Total polyphenols, flavonoid and tannin contents were determined colorimetrically and some of these molecules were identified using RP-HPLC. A significant difference on phenolic contents and composition were found among the investigated plants. Cymbopogon schoenanthus was the richest in phenolic compounds (approx. 72%) with quercetine-3-o-rhamnoside (approx. 33%) as main contributor. For all the tested plants, the highest antioxidant capacity was detected in the ethanolic extracts rather than in the aqueous ones. The highest antiproliferative potential was observed for the ethanolic extracts. Hammada scoparia, Retama raetam and Zizyphus lotus exhibited important antiproliferative effect that reached 67% at a 1% extract concentration. Taken together, the present study supports the potential development of chemotherapeutic agents from, at least, four of the five studied Tunisian ethnomedicinal plants.

Phenolic contents were determined in S. kali leaves, stems, and roots at the beginning, the mid and the end of the vegetative period, as well as the floral bud and open flower at the reproductive stage. Antioxidant and antimicrobial activities were also assessed. Moreover, the major metabolites were identified by HPLC. Results showed a maximum of total phenol contents in the photosynthetic organs, followed by stems and roots. A similar tendency was found for the flavonoids and condensed tannins. Concerning antioxidant analysis, antiradical and Fe-reduced activities were higher in leaves and stems whereas Fe-chelating activity was higher in leaves and roots. Independently of the plant organ, total phenol and flavonoid contents were maximal at the end of the vegetative period whereas tannin content was maximal at the reproductive one. Phenolic contents were related to the organ, the development stage, and their interaction. Concerning the antimicrobial activity, stem extracts were the most efficient against human pathogen strains (Bacteria: Staphylococcus epidermidis, Staphylococcus aureus, Micrococcus luteus, Escherichia coli and Pseudomonas aeruginosa. Fungi: Candida kefyr, C. holmii, C. albicans, C. sake and C. glabrata). Moreover, nine natural products were identified in leaf and stem extracts of S. kali known for their biological activities. As a whole, biological activities of S. kali seem to be strongly related to organs and to the development stage. The phytochemical tests by HPLC demonstrated the presence of nine compounds among them two alkaloids: salsoline and fraxidin. Some molecules are presented in both organs (salsoline, resorcinol, luteolin 7-o-glucoside; and hyperoside). Therefore, endogenous factors greatly account for the biological potential of this medicinal halophyte.

Since ancient times, plants have been the main source of bioactive molecules, such as phenolic compounds, capable of remedying various diseases. However, polyphenols' content and efficiency vary greatly as a function of several intrinsic and extrinsic factors. To optimize the procedure for the extraction of active molecules from the medicinal plant Verbena officinalis, effects of the plant origin, selected solvent, and extraction method were assessed. V. officinalis aerial parts were collected in two different regions of Tunisia (Bizerte and Ain Draham), and their bioactive molecules were extracted by maceration, decoction, and by the Soxhlet apparatus, either with water or with ethanol. Significant variability in the extracts' contents of phenolic compounds as well as their antioxidant and antimicrobial capacities were noted depending on the different studied factors. In particular, ethanol extracts were found to generally contain higher concentrations of phenolic compounds and more potent antioxidant capacities than water extracts. However, when tested against various pathogenic bacteria, water extracts were most often at least as active as ethanol extracts to inhibit bacteria growth in vitro. Finally, differences were also observed between V. officinalis samples from Bizerte compared to Ain Draham area. All of these results emphasize the need of adapting various parameters for the optimal extraction of bioactive molecules from a medicinal plant such as V. officinalis.Évaluation de différents procédés d’extraction des composés phénoliques d’une plante médicinale : Verbena officinalis.Depuis la nuit des temps, les plantes ont été la source principale de molécules bioactives, tels les composés phénoliques, capables de remédier à diverses maladies. Cependant, le contenu et l’activité des polyphénols dépendent d’un certain nombre de facteurs intrinsèques et extrinsèques. Dans le but d’optimiser les procédés d’obtention des principes actifs de la verveine (Verbena officinalis), les effets de la provenance de la plante, du solvant et de la méthode d’extraction ont été évalués. Ainsi, la partie aérienne de V. officinalis a été collectée dans deux régions différentes de la Tunisie (Bizerte et Ain Draham). L’extraction a été réalisée par macération, décoction et par l’appareil de Soxhlet tantôt avec de l’eau tantôt avec de l’éthanol pur. Une variabilité significative des teneurs en composés phénoliques ainsi que des capacités antioxydantes et antimicrobiennes des extraits a été observée en fonction des facteurs étudiés. De manière générale, les extraits éthanoliques sont plus riches en composés phénoliques et présentent des activités antioxydantes plus fortes que les extraits aqueux. Cependant, vis-à-vis de différentes souches pathogènes, les extraits aqueux sont souvent au moins aussi puissants que les extraits éthanoliques pour inhiber la croissance bactérienne in vitro. De plus des différences notables sont observées selon que V. officinalis provient de la région de Bizerte ou d’Ain Draham. Ces résultats montrent que la prise en compte de plusieurs paramètres est nécessaire pour optimiser l’efficacité des procédures d’extraction des molécules bioactives de V. officinalis.

Salinity and potassium deficiency are major abiotic constraints affecting plant growth, productivity, and metabolism. The present work was conducted to check whether salinity alleviates, aggravates, or does not affect the effects of potassium deficiency on Sulla carnosa, a salt-tolerant legume common in diverse saline soils. We investigated the changes in plant growth, phenolic compound composition, and antioxidant activity in stems and roots of this species grown hydroponically under different conditions: C, control (complete nutrient solution containing 6 mM K+ and not added with NaCl); KD, K+ deficiency (K+-deficient nutrient solution (60 μM K+) not added with NaCl); C + S, salt treatment (control nutrient solution containing 6 mM K+ and added with 100 mM NaCl); and KD + S, combined treatment between salinity and K+ deficiency (K+-deficient nutrient solution (60 μM K+) added with 100 mM NaCl). Results showed that all treatments applied led to a significant decrease of root and stem growth, with a more marked reduction in plants exposed to the combined stresses, suggesting synergistic effects of salinity and K+ deficiency. In addition, results indicated that both stresses either applied alone or in combination quantitatively or qualitatively modulated phenolic compound accumulation and their antioxidant activities. But a predominance of K+ deficiency effect was noticed, which may be considered as a suitable manipulation for the production of antioxidants compared to the other treatments.

This work aims to characterize Thymus capitatus essential oil and to investigate its preservative effects on raw milk quality alone or combined to pasteurization heat treatment. To study its preservative effect, 1 mg l(−1) of T. capitatus essential oil, characterized by GC-MS, was added to pasteurized or raw milk. The evaluation of milk quality was made by consulting samples total acidities, peroxide values and their total microbial counts, as compared to control milks. Assays were made immediately and after every 48 h of incubation at room temperature throughout 6 days. Results showed that the incorporation of T. capitatus EO to pasteurized milk was the most efficient treatment that inhibited milk deterioration. Combining pasteurization to EO incorporation into raw milk inhibited completely the contaminant bacterial growth to the second day of incubation. Moreover, until the fourth day, no statistical differences have been recorded on the total acidity of incorporated and pasteurized milk samples, while raw milk acidity exceeded 55 g of lactic acid equivalent l(−1). Considering milk fat oxidation, adding T. capitatus EO to pasteurized milk has significantly retarded milk peroxide production to day 4. In conclusion, Thymus capitatus essential oil, combined to pasteurization, presents an interesting potency to act as milk stabilizer.

This work aimed to nanoencapsulate Thymus capitatus essential oil as natural food preservative. To fix ingredients type and concentrations, preliminary formulations were tested for their droplet size average and distribution. Emulsions stability was investigated for 12 days and the antibacterial activity of bulk and encapsulated essential oil were studied. Results showed that nanoemulsions containing 1% of SDS as emulsifier and 10% of dispersed phase containing 70% of the essential oil have an appropriate droplet diameter averages (around 110 nm). Stability tests demonstrated that nanoemulsions, stored at 4 °C, showed the highest stability. Moreover, antibacterial activity results exhibited the improvement of encapsulated T. capitatus essential oil efficiencies as compared to bulk one. In fact, nanoemulsion presented higher bacterial growth inhibition, lower minimum inhibitory and bactericidal concentrations, and better time kinetic results, as compared to bulk one. Gathered results provide useful information for designing effective natural preservatives that inhibit food bacterial spoilage.

In the present study, a nanoemulsion was developed to improve the functional performance of Thymus capitatus essential oil (thyme EO) as natural food preservative. Thyme EO was submitted to phytochemical prospection and its safety limit was evaluated by acute oral toxicity. Hereafter, the EO was nanoencapsulated and the antioxidant and antibacterial activities of bulk and encapsulated EO were examined. Results showed that concentrations up to 2 g·kg− 1 b.w. of T. capitatus EO did not present any toxic effects. Moreover, results exhibited an enhancement of nanoencapsulated EO antibacterial activity. In fact, nanoemulsion demonstrated higher growth inhibition diameters than free EO (15.8 and 9.8 mm, against Staphylococcus aureus, respectively). Furthermore, nanoemulsion exhibited significant lower minimum inhibitory concentration against all tested bacteria than bulk EO. However, nanoencapsulating T. capitatus EO decreased significantly its antioxidant activity. Indeed, for DPPH test, free EO IC50 concentrations were considerably lower than those of the nanoencapsulated form (300 and 390 μg·mL− 1, respectively). As well, the capacity of T. capitatus EO to inhibit the β-carotene bleaching has been reduced after its nanoencapsulation. These results provide useful information for designing effective natural preservative able to inhibit food bacterial spoilage.

This research studies the application of a specific nanoemulsion as anti-Escherichia coli agent. The specific mixture was generated by a simplex-centroid design. Physicochemical parameters such as droplet average diameter, pH, viscosity, density, turbidity, whitening index, refractive index, stability (thermal, physical, and osmotic stability), and antibacterial activity kinetic, have been assessed. The mixture nanoemulsions had droplet diameters significantly smaller than those of clove or cinnamon nanoemulsions. Individual and mixture essential oils nanoemulsion exhibited appropriate stability under pH, thermal, and ionic stress as well as after mid-term storage. Antibacterial activity kinetic revealed the fast and pronounced efficacy of mixture nanoemulsions on E. coli (reach 98% of growth inhibition), especially for the nanoemulsion composed of 50% essential oil in the dispersed phase upon 20 days of storage. All data considered, the actual work evidences the promising advantages of using specific nanoemulsions as delivery systems of antibacterial agents in the beverage and food industry.

Salinity and K+ deficiency are two environmental constraints that generally occur simultaneously under field conditions, resulting in severe limitation of plant growth and productivity. The present study aimed at investigating the effects of salinity, either separately applied or in combination with K+ deficiency, on growth, photosynthetic performance, secondary metabolites content, and related antioxidant capacity in Sulla carnosa. Seedlings were grown hydroponically under sufficient (6000 μM) or low (60 μM) K+ supply with 100 mM NaCl (C + S and D + S treatments, respectively). Either alone or combined with K+ deficiency, salinity significantly restricted the plant growth. K+ deficiency further increased salt impact on the photosynthetic activity of S. carnosa, but this species displayed mechanisms that play a role in protecting photosynthetic machinery (including non photochemical quenching and antioxidant activity). In contrast to plants subjected to salt stress alone, higher accumulation of phenolic compounds was likely related to antioxidative defence mechanism in plants grown under combined effects of two stresses. As a whole, these data suggest that K+ deficiency increases the deleterious effects of salt stress. The quantitative and qualitative alteration of phenolic composition and the enhancement of related antioxidant capacity may be of crucial significance for S. carnosa plants growing under salinity and K+ deficient conditions.

In this study, six medicinal halophytes ( Daucus carota, Frankenia laevis , Inula crithmoides , Plantago coronopus , Raphanus raphanistrum and Tamarix gallica ) were examined for their phenolic pools, antioxidant (DPPH, ABTS, superoxide radical scavenging and iron-reducing tests), antibacterial (micro-dilution method) and anti-tyrosinase activities. RP-HPLC analysis of the six halophytes showed that D. carota and F. laevis exhibited the highest phenolic contents, with chlorogenic acid (6.6 mg/g DW) and catechin (15.4 mg/g DW) as the major compounds, respectively. In addition, D. carota and F. laevis shoots exhibited the best antioxidant capacities as shown by low IC 50 values against DPPH, ABTS, and superoxide anion radicals, and strong iron-reducing capacity. Moreover, F. laevis extracts exhibited a broad-spectrum antibacterial activity against the four human pathogenic strains tested, mainly Micrococcus luteus and Salmonella enterica . D. carota efficiently inhibited Staphylococcus aureus and S. enterica growth. Interestingly, the strongest inhibition of melanin synthesis was found in D. carota and F. laevis , both species inhibiting particularly diphenolase activity. These data suggest that D. carota and F. laevis shoots could be used as effective biomolecules and also as new natural skin-whitening agents.

The objective of this study is to evaluate the effect of either a solution of Thymus capitatus essential oil or its nanoemulsion on the quality of milk contaminated by bacteria. After 24h of S. aureus inoculation, bacterial growth reached 202×10(3)CFU/ml in the presence of the essential oil while it was limited to 132×10(3)CFU/ml when treated with nanoemulsion. The reduction of antioxidant capacity of milk treated with essential oil was higher when treated with nanoemulsion. Moreover, free essential oil was more efficient in protecting proteins from degradation than the nanoemulsion. For instance, after 24h of E. hirae contamination, 26% of the total proteins were consumed in the presence of nano-encapsulated essential oil, while only 14% of the initial content was consumed when free essential oil was added. Concerning milk acidity increase and the inhibition of peroxide production, no statistical differences have been recorded between the use of free essential oil or its nano-emulsion. In conclusion, bulk or nano-encapsulated T. capitatus essential oil preserve milk quality and can extend its shelf life.

Essential oils (EOs) are natural, volatile and aromatic liquids extracted from special plants. EOs are complex mixture of secondary metabolites (terpenes, phenolic compounds, alcohol). EOs possess a wide range of biological activities including antioxidant, antimicrobial and anti-inflammatory ones. Particularly, EOs exhibit pronounced antibacterial and food preservative properties that represent a real potential for the food industry. Numerous EOs have the potential to be used as a food preservative for meat and meat products, vegetables and fruits as well as for dairy products. The main obstacles for using EOs as food preservatives are their safety limits, marked organoleptic effects and possible contamination by chemical products such as pesticides. This review aims to provide an overview of current knowledge about EOs food preservative properties with special emphasis on their antibacterial activities and to support their uses as natural, eco-friendly, safe and easily biodegradable agents for food preservation.

This study investigates the optimal combination of clove, cinnamon, lavender, and myrtle essential oils (EOs) against Escherichia coli. After the GC/MS analyses, the antimicrobial activities of the four EOs were screened. Afterward, a statistical mixture design established the right EOs’ combination capable of protecting milk from E. coli. Results illustrated that the EOs were chemically different and efficient against 14 bacteria. Hence, the simplex‐centroid mixture design was used to build polynomial models describing the relationship between the anti‐E. coli effect and the proportion of each EO. Result depicted that the lowest bacterial survivability was equal to 1.5 × 10⁶·CFU·ml⁻¹ for the combination of cinnamon and lavender; and the combination of cinnamon, lavender, and clove at a concentration of 2 mg/ml. The application of the statistical design concluded that the optimal combination corresponds to 2.4% S. aromaticum, 38.2% L. stoechas, and 59.4% C. zeylanicum. The combination validation exhibited its efficiency as it restricted the E. coli viability to 1 × 10⁶·CFU·ml⁻¹. PRACTICAL APPLICATIONS: EOs are the new eco‐friendly preservative for food. Their combination (using the right sources and proportions) allows better protection against germs. In this study, the obtained formula may be of interest in the milk and dairy industry as it contributes to protecting milk (and dairy products) against E. coli contamination.

The effects of potassium (K + ) deficiency were investigated in Sulla carnosa plants. Plants were grown hydroponically for one month in K + -sufficient (6 mM K + , Control) and K + -deficient (60 μm K + ) solutions inside the greenhouse in Biotechnology Center of Borj Cedria, Tunisia. Growth, water status, pigment contents, photosynthetic gas exchange, photosystem II (PSII) photochemistry and leaf principal secondary metabolites (polyphenols, flavonoids, and condensed tannins), and their antioxidant properties (DPPH (1.1-diphenyl-2-picrylhydrazyl) scavenging capacity, ferric reducing power, chelating effect on ferrous ions, and β-carotene bleaching test) were determined. Growth of vegetative organs was decreased by some 50% by K + deficiency with stems more affected (−68%) than roots (−42%) and leaves (−45%). Water content decreased in the three vegetative organs. Photosynthetic gas exchange and pigment contents were affected by low K + conditions. In contrast to condensed tannins which remained constant, total polyphenols and flavonoids contents increased under K + deficiency (by 62.7 and 14.5%, respectively). Furthermore, total antioxidant activity increased by 33.5% compared to control plants. Except for β-carotene bleaching test that increased, DPPH scavenging capacity, ferric reducing antioxidant power, and chelating effect on ferrous ions decreased owing to K + deficiency. An increased and/or de novo synthesis of individual polyphenols was also observed by RP-HPLC analysis. As a whole, these data suggest that S. carnosa was able to modulate the metabolism of secondary metabolites and their antioxidant activity under conditions favouring reactive oxygen species (ROS) production in order to minimize the deleterious effects of these oxygen species.

This work focuses on the variability of Retama raetam (Forssk.) Webb bioactive compounds as a function of the plant cycle. The main results showed that it exhibited the highest percentage of polyunsaturated fatty acids, along with superior levels of vitamin C and total phenolic compounds (66.49%, 645.6 mg&middot, 100 g&minus, 1 FW and 23.9 mg GAE&middot, g&minus, 1, respectively) at the vegetative stage. Instead, at the flowering and mature fruiting stages, R. raetam (Forssk.) Webb exhibited notable contents of proline (25.4 &mu, mol&middot, 1 DW) and carotenoids (27.2 &mu, g&middot, 1 FW), respectively. The gathered data concerning the antioxidant activity highlighted the effectiveness of the vegetative stage in comparison to the other periods. Actually, IC50 and EC50 values of the hydromethanolic extract obtained from the plant shoots at the vegetative stage were of 23, 380, 410, 1160 and 960 &mu, mL&minus, 1 (DPPH&bull, and ABTS&bull, + radicals scavenging activity, reducing power, chelating power and &beta, carotene bleaching activity, respectively). Furthermore, the four studied stages showed appreciable antibacterial capacities against human pathogens with a higher efficiency of the vegetative stage extract. Finally, the LC-DAD-ESI/MSn analysis revealed the predominance of isoflavonoids as main class of phenolic compounds and demonstrates that individual phenolic biosynthesis was clearly different as a function of plant growth. These findings highlight that reaching the optimum efficiency of R. raetam (Forssk.) Webb is closely linked to the physiological stage.

The aim of this work was to investigate the physicochemical, nutritional and antioxidant properties of traditionally pressed edible (roasted argan kernels) and beauty (unroasted argan kernels) Algerian argan oil. Oxidative stability and the quality of oils (acidity, peroxide index, K₂₃₂, and K₂₇₀) were slightly affected by roasting process. But, any case, none of the analyzed oils surpassed limits established by Moroccan norms and were labeled as “extra virgin oil.” In addition, the better antioxidant capacities of argan oil prepared from roasted seeds could be explained by a better extractability of carotenoids, phenolics. and tocopherols as compared with unroasted ones. The dominant fatty acids found consisted by oleic acid followed by linoleic, palmitic, and stearic acids and the major triglycerides were principally formed by two or three oleic acid residues. According to our data, the roasting process does not influence the quality of the argan oil and confirm its good stability. PRACTICAL APPLICATIONS: Argania spinosa (Sapotaceae family) is an endemic xero‐thermophilic species from the southwestern region of Algeria (Tindouf countryside) and Morocco. Argan oil is the most important products derived from Argan tree. Despite its wide spread uses and properties, only few studies had been carried out on the traditionally extracted roasted (edible) and unroasted (for beauty uses) Algerian argan oil. Thus, this study aimed to valorize this oil through their physicochemical, nutritional and antioxidant properties in order to situate this local product to the standards and international norm values.

Total phenol content and the antioxidant activities of three cultivars of Opuntia ficus-indica (L.) Mill. were evaluated. The results show that the ecotypes were significantly different according to their fatty acid composition, antioxidant and antibacterial activity, as well as their polyphenol profiles. Rossa fruit collected in August exhibited the higher phenolic content (15.48 mg GAE g−1 DW) with a stronger antioxidant activity. Bianca fruit collected in August exhibited a lower phenolic content (3.13 mg GAE g−1 DW) together with the stronger antiradical activity (96.14%). The advantage of this ecotype was more discernible as compared to positive controls butylated hydroxytoluene (BHT, 79.75%). Likewise, CpG chromatogram identification revealed also an important difference between the ecotypes on oleic and linoleic acids.Keywords: Opuntia ficus-indica, variability, phenol content, fatty acid, antioxidant activity.African Journal of Biotechnology Vol. 12(40), pp. 5875-5885

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.

Reaumuria vermiculata is a xero-halophytic specie widely distributed in the south of Tunisia. In the current study, antioxidant, anti-inflammatory and anticancer activities of Reaumuria vermiculata shoot extracts as well as its phenolic compounds were investigated in different solvent extracts (hexane, dichloromethane, methanol and water). Results showed a strong antioxidant activity, using the ORAC method and a cell based-assay, in methanol extract as well as an important phenolic composition (117.12 mg GAE/g). Hexane and dichloromethane proved an interesting anticancer activity against A-549 lung carcinoma cells, with IC50 values of 17 and 23 μg/ml, respectively. Besides, dichloromethane extract displayed the utmost anti-inflammatory activity, inhibiting NO release over 100 % at 80 μg /ml in LPS-stimulated RAW 264.7. Taken together, these finding suggest that R. vermiculata exhibited an interesting biological activities which may be related to the phenolic composition of this plant. Moreover, the identification of phenolic compounds in R. vermiculata dichloromethane extract using RP-HPLC revealed that myricetin was the major molecule. These results allow us to propose R. vermiculata as a valuable source for bioactive and natural compounds exhibiting interesting biological capacities., EXCLI Journal;Vol. 15, 2016

Dunaliella salina (Dunal) Teodor, when treated over 25 d with a wide range of NaCl salinities (0.6-4.5 M), showed its maximal growth potentialities at 1.5-3.0 M NaCl and was able to survive even at 4.5 M NaCl. Sodium concentrations increased significantly at the supraoptimal salinities, reaching up to 5 mmol · g(-1) dry weight (dwt) at 4.5 M NaCl. Interestingly, ability of D. salina to take up essential mineral nutrients was not impaired by increased salinity. As for growth, chl concentrations were maximal in the 1.5-3.0 M NaCl range. Interestingly, carotenoid concentrations increased with the increasing salinity. The highest values of total antioxidant activity (5.2-6.9 mg gallic acid equivalents [GAE] · g(-1) dwt), antiradical activity, and reducing power were measured at 1.5-3.0 M NaCl. As a whole, these results showed that at 1.5-3.0 M NaCl, D. salina produce appreciable antioxidant level. But, once it reaches its growth maximum, a salt addition up to 4.5 M could enhance its carotenoid yield.

The antioxidant capacities of the crude extract, aqueous and ethyl acetate partitions of Limoniastrum guyonianum Boiss. (Zita) were investigated in this study. The ethyl acetate phase exhibited a significant antioxidant activity as judged by total antioxidant activity, DPPH test and reducing power. Fractionation of this extract by centrifugal partition chromatography (CPC) using quaternary Arizona solvent systems composed of n -heptane/ethyl acetate/methanol/water led to ten fractions. The antioxidant capacities of these fractions were assessed using the same previous tests. Fraction 8 showed the highest antioxidant capacity (1291.1 mg GAE/g DR), the power ability to quench DPPH radical (IC 50 = 2 μg/ml) and to reduce Fe 3+ (EC 50 = 65 μg/ml). From this fraction, three powerful flavonoids were isolated ( 1 – 3 ): gallocatechin ( 1 ), epigallocatechin ( 2 ) and epigallocatechin-3- O -gallate ( 3 ). These findings suggest that the antioxidative property of L. guynianum is may be related to the presence of these flavonoids, which can be used in various industrial fields.

Suaeda fruticosa is an edible and medicinal halophyte known for its hypoglycaemic and hypolipidaemic activities. In this study, novel biological activities of the shoot extracts related to their phenolics were investigated. Results showed an appreciable total phenolic (31.8 mg GAE/g DW) in shoot extracts. The estimation of antioxidant capacities using oxygen radical absorbance capacity (ORAC method) and a cell based-assay (WS1) of four extracts (hexane, dichloromethane, methanol and water) showed that shoot methanol extract exhibit the highest antioxidant activities. The same extract displayed the utmost anti-inflammatory activity, inhibiting nitric oxide (NO) release, by 66.4% at 160 μg/ml in lipopolysaccharide (LPS)-stimulated RAW 264.7 macrophages. Besides, the dichloromethane extract showed the highest anticancer activity against human lung carcinoma (A-549) and colon adenocarcinoma cell lines (DLD-1, Caco-2 and HT-29) with specificity against DLD-1 (IC50 = 10 ± 1 μg/ml). These findings demonstrate the remarkable potentiality of this edible halophyte as valuable source of antioxidants which exhibit original and interesting anti-inflammatory and anticancer capacities.

Mesembryanthemum edule is an edible medicinal halophyte traditionally used to treat several human diseases. In this study, particular importance was attached to the influence of environmental conditions on phenolic composition and antioxidant activities of two M. edule provenances from contrasting climatic regions (Djerba and Monastir sampled from arid and superior semi-arid bioclimatic stages, respectively). Shoot phenolic content was evaluated using colorimetric method and its composition was identified by HPLC analysis with or without thiolysis. Antioxidant activities were assessed by five in vitro antioxidant systems. Results showed that the two M. edule provenances were significantly different according to their antioxidant activity as well as their polyphenol profiles. Indeed, plants from Djerba (lack of rainfall and long light hour periods) exhibited stronger antioxidant activity together with higher phenolic content. For instance, Djerba provenance shoots showed much lower IC 50 (4.8 μg ml −1 ) and EC 50 (80 μg ml − 1 ) values for DPPH and Fe-reducing tests, respectively. In addition, the superiority of this provenance (Djerba) was more marked as compared to positive controls (BHT, BHA, and VitC). HPLC identification revealed also an important difference between the two provenances on major flavonoid components. This difference was confirmed by the mean degrees of tannin polymerization (DP n ) which was higher in Djerba plants. These data suggest that M. edule adaptation to environmental stresses proceeds through induced particular phenol quality and DP n for the improvement of their antioxidant capacities to protect plant tissues against oxidative stress.

Dunaliella salina (Dunal) Teodor, when treated over 25 d with a wide range of NaCl salinities (0.6-4.5 M), showed its maximal growth potentialities at 1.5-3.0 M NaCl and was able to survive even at 4.5 M NaCl. Sodium concentrations increased significantly at the supraoptimal salinities, reaching up to 5 mmol · g(-1) dry weight (dwt) at 4.5 M NaCl. Interestingly, ability of D. salina to take up essential mineral nutrients was not impaired by increased salinity. As for growth, chl concentrations were maximal in the 1.5-3.0 M NaCl range. Interestingly, carotenoid concentrations increased with the increasing salinity. The highest values of total antioxidant activity (5.2-6.9 mg gallic acid equivalents [GAE] · g(-1) dwt), antiradical activity, and reducing power were measured at 1.5-3.0 M NaCl. As a whole, these results showed that at 1.5-3.0 M NaCl, D. salina produce appreciable antioxidant level. But, once it reaches its growth maximum, a salt addition up to 4.5 M could enhance its carotenoid yield.

Changes in phenolic composition and biological activities were investigated in different Limoniastrum monopetalum L. organs. For that, 80% aqueous acetone extracts were used to estimate total phenolic contents and their antioxidant activities were evaluated using DPPH· and O 2 ·− radical scavenging activities and reducing power. The efficiency of organ extracts was tested against human pathogen strains. Ultimately, acid hydrolysis of all organs was subjected to RP-HPLC for phenolic identification. Results showed that flower extracts exhibited the highest polyphenol (65.42 GAE/g DW) and flavonoid (35.36 CE/g DW) contents. Stems were enriched in condensed tannin content (21.4 mg CE/g DW) and displayed the best antiradical activities and the highest reducing power. Besides, stem and gall extracts showed the highest efficiency against pathogenic bacteria as compared with those of flower. Concerning the antifungal test, a slight activity was found in gall extracts. The RP-HPLC showed a difference in phenolic compounds that varied as function of organ. In fact, the major phenolic compound varied as function of organ. Results suggest that L. monopetalum could be a promising source of biomolecules for therapeutic and nutraceutical industries and the difference between organs may be related to their physiological role.

Organic wastes were successfully used as soil amendment to improve agrosystems productivity. Yet, the effectiveness of this practice to enhance plant antioxidant capacities has received little attention. Here, we assess the effect of municipal solid waste (MSW) compost (at 40 t ha−1) on growth, polyphenol contents and antioxidant activities of Mesembryanthemum edule. MSW compost application significantly increased the soil contents of carbon, nitrogen, calcium, phosphorus and potassium. This was associated with higher nutrient (N, P, and K) uptake, which likely led to the significant improvement of the plant biomass and relative growth rate (RGR) (+93% on average) as compared to the control. In the same way, the fertilizing effect of the added organic matter significantly enhanced the antioxidant potential M. edule, assessed by radical scavenging activity, iron reducing power and β-carotene bleaching capacity. This was associated with significantly higher antioxidant contents, mainly total phenols and flavonoids. Heavy metal (Pb, Cd, Cu, and Zn) concentrations were slightly increased upon compost application, but remained lower than phytotoxic values. Overall, our results point out that short-term MSW compost application at 40 t ha−1 is efficient in enhancing the productivity together with the antioxidant potentiality of M. edule without any adverse environmental impact.

Limoniastrum monopetalum is a traditional medicinal species which leaf infusion exhibits antidysenteric properties against infectious diseases. In this study, ten kinds of leaf extracts were used to examine the effect of extraction solvent system with varying polarities on polyphenol contents and DPPH scavenging activity. Then the superoxide scavenging activity and the reducing power of the most promising solvent extracts were evaluated too. Moreover, the efficiency of the best leaf extract has been investigated against pathogenic bacteria and yeast. Eventually leaf extract was hydrolyzed by acid and the phenolics identified by RP-HPLC. Results showed that phenolic contents and antioxidant activities varied considerably as function of solvent polarity. Leaf extract using pure methanol showed the highest polyphenol content (15.85 mg GAE/g DW). Moreover, antiradical capacities against DPPH and superoxide, and reducing power were maxima in acetone/water (8:2) of leaf extract. However, the latter showed a slight antimicrobial activity against human pathogen strains such as Staphylococcus aureus, Micrococcus luteus and Candida holmii. The HPLC analysis revealed several phenolic compounds in L. monopetalum leaf including vanillic and gallic acids as major phenolics. Our findings identified the appropriate solvent for extracting halophyte phenolics which might provide a rich and novel source of natural antioxidants as food additives replacing synthetic ones in food industry.

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.

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.

This study compared phenolic contents and antioxidant activity in different organs of Acacia albida (leaves and bark) and focuses on identification of phenolic compounds of leaves by HPLC-DAD. The analysed organs exhibited differences in total polyphenol contents (100 and 59.5 mg GAE g− 1 DW). Phenolic contents of leaves were two times higher than those in bark. Ethanolic extracts exhibited good antioxidant activities with IC50 = 26 μg mL− 1 for DPPH and EC50 = 50 μg mL− 1 for FRAP. Identification by HPLC-DAD revealed the presence of nine phenolic compounds known for their high antioxidant activity. The results suggested that this species can be used as source of natural antioxidants.

This study compared phenolic contents and antioxidant activity in different organs of Acacia albida (leaves and bark) and focuses on identification of phenolic compounds of leaves by HPLC-DAD. The analysed organs exhibited differences in total polyphenol contents (100 and 59.5 mg GAE g(-1) DW). Phenolic contents of leaves were two times higher than those in bark. Ethanolic extracts exhibited good antioxidant activities with IC50 = 26 μg mL(-1) for DPPH and EC50 = 50 μg mL(-1) for FRAP. Identification by HPLC-DAD revealed the presence of nine phenolic compounds known for their high antioxidant activity. The results suggested that this species can be used as source of natural antioxidants.