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Opuntia dillenii has been used in folk medicine as a natural remedy for its diverse biological activities and bioactive compounds. The present study aimed to quantify the bioactive substances of cladode extracts (aqueous and ethanolic) of O. dillenii from Djerba Island, Tunisia and evaluate their antioxidant, antimicrobial and cytotoxic potentials. The results showed that O. dillenii cladodes had a high amount of total phenolic content (TPC) and total flavonoid content (TFC). Interestingly, by LC-MS analysis, we found that most of the phenolic and volatile compounds were present in the ethanolic extract. Indeed, quinic acid (58.78 µg/g), quercetin (11.5 µg/g), rutin (7.02 µg/g), luteolin (4.93 µg/g), cirsiliol (3.22 µg/g) were the major phenolic compounds in O. dillenii ECE. GC-MS analysis of O. dillenii ACE and ECE revealed that n-hexadecanoic acid (13.08%), and stigmastan-3, 5-diene (6.97%) were the main volatile compounds detected in ECE. Correlation analysis showed that the TPC and TFC were significantly correlated with the antioxidant, antimicrobial and cytotoxic activities. Staphylococcus aureus, Micrococcus luteus, and Fusarium oxysporum were found to be the most sensitive strains. Finally, the human colon carcinoma cell line Caco-2 was more sensitive to aqueous and ethanolic extracts with an IC50 = 50.89 ± 0.01 µg/mL and IC50 = 40 ± 0.01 µg/mL, respectively than K-562 cell line. more...

Background Hyperactivation of mechanistic target of rapamycin (mTOR) signaling pathway is involved in the regulation of cellular growth, proliferation, and more in general, is a common phenomenon in most types of cancers. Thus, natural substances targeting this pathway can be of great therapeutic potential in supporting the treatment of tumor patients. Rhus tripartita (Ucria) Grande is a plant growing in desertic areas which is traditionally used for the treatment of several diseases in Tunisia. In the present work, the biochemical profile of the main compounds present in the plant leaf extract was determined and the anti-leukemic potential of the plant extracts against acute monocytic leukaemia (AML) THP-1 cells was investigated. Methods After HPLC identification of some phenolic compounds present in the plant extract and the quantification of saponin content, the cytotoxic effect of Rhus tripartita extracts on THP-1 cell culture was evaluated using the colorimetric MTT assay for cell viability. THP-1 cells were incubated with medium containing the relative IC50 concentrations of total plant extract, saponin extract and some standard compounds (rutin (R); kaempferol (K); mixture of catechin, epicatechin, and epicatechin-gallate (CEEG); ellagic acid (EA). Finally, qRT-PCR and western blotting analysis were used to evaluate the effect of some flavonoids present in a crude extract of polyphenols and the total extract of saponins on cell survival and apoptosis. Results Analysis of expression level of some gene (PIK3CA, PTEN, AKT1, mTOR, EIF4E, RPS6KB1, and TSC1) involved in the mTOR pathway and the phosphorylation of S6 and AKT proteins allowed to observe that a total Rhus tripartita extract and some of the compounds found in the extract controls THP-1 cell proliferation and apoptosis via regulation of the PI3K-Akt-mTOR signaling pathway. Conclusion Rhus tripartita-induced inhibition of cell cycle and induction of apoptosis may involve the mTOR pathway. Therefore, Rhus tripartita extract may be a useful candidate as a natural anti-cancer drug to support the treatment of AML. more...

The aim of this study was to investigate the polyphenolic profile and biological properties of leaves acetonic extracts from six Tunisian spontaneous plants of Marrubium vulgare L., Rhus tripartita (Ucria) D.C., Hernaria fontanesii J. Gay subsp. fontanesii, Ziziphus lotus L., Plantago ovata Forsk., Thymelaea hirsuta (L.) Endl. Bioassay-guided and HPLC-PDA-ESI-MS procedures demonstrated that R. tripartita contained the highest amount of phenolic compounds (1475.1 µg/g), followed by Z. lotus (1087.8 µg/g) and P. ovata (1027.6 µg/g). Interestingly, in R. tripartita myricetin‐3-O-galactoside turned out to be the most abundant one. The plant extracts showed antimicrobial efficacy against Listeria monocytogenes, Staphylococcus aureus and S. epidermidis including methicillin resistant strains; no activity was detected against Gram-negative bacteria. R. tripartita revealed the best MIC and MBC values and caused significant decrease of S. aureus biofilm. Both R. tripartita and Z. lotus did not display any toxicity against Artemia salina Leach (LC50 > 1000 μg/mL). more...

Allium roseum is an important medicinal and aromatic plant, specific to the North African flora and a rich source of important nutrients and bioactive molecules including flavonoids and organosulfur compounds whose biological activities and pharmacological properties are well known. In the present study, the inhibition of amyloid beta protein toxicity by the ethanolic extract of this plant is investigated for the first time. Preliminary biochemical analyses identified kæmpferol and Luteolin-7-o-glucoside as the more abundant phenolic compounds. The effects of A. roseum extract (ARE) on amyloid beta-42 (Aβ42) aggregation and aggregate cytotoxicity, were investigated by biophysical (ThT assay, Dynamic light scattering and transmission electron microscopy) and cellular assays (cytotoxicity, aggregate immunolocalization, ROS measurement and intracellular Ca2+ imaging). The biophysical data suggest that ARE affects the structure of Aβ42 peptide, inhibits its polymerization, and interferes with the path of fibrillogenesis. The data with cultured cells shows that ARE reduces Aß42 aggregate toxicity by inhibiting aggregate binding to the cell membrane and by decreasing both oxidative stress and intracellular Ca2+. Accordingly, ARE could act as a neuroprotective factor against Aβ aggregate toxicity in Alzheimer’s disease. more...

Allium roseum L., a spontaneous comestible species in North Africa, presented a nutraceutical potential in terms of essential nutrients and phytonutrients responsible for health benefits. In the present study, growth parameters, soluble sugars, principal secondary metabolites contents (total polyphenols, vitamin C) and their antioxidant properties were determined in A. roseum subjected to salt or drought stresses during 30 days. Plants were subjected to drought stress by suspending watering, while other plants were submitted to salt stress through irrigation with a nutrient solution containing 50, 100, 150 and 200 mM NaCl. The obtained results reveal that salt and drought stress did not significantly affect the growth parameters (p ≥ 0.05), while these stressful conditions increased the bulbs dry matter. Moreover, the applied salt and drought stresses increased the soluble sugars, total polyphenols and vitamin C contents of the plant. Cultivating A. roseum under drought or salt stresses could be a good alternative to valorize antioxidant molecules from this species in industrial applications. more...

Context The present study deals with new biological properties of the wild edible Diplotaxis simplex (Viv.) Spreng (Brassicaceae). Objectives The current study evaluates the antioxidant, the anti-inflammatory and the anti-cancer properties of ethyl acetate and ethanol extracts from D. simplex flowers. Materials and methods The anti-proliferative activity of the extracts (10-70 μg/mL) was assessed by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) against human colon cancer cell line Caco-2. The anti-inflammatory potential was evaluated by the inhibitory effect of the extracts (1.5-7.5 mg/mL) on phospholipase A2 activity as well as on carrageenan-induced paw oedema in mice. Extracts (200 mg/kg) or indomethacin (50 mg/kg) as positive control were injected intraperitoneally for albino mice prior to the induction of the oedema by carrageenan. Antioxidant activities were investigated using various complementary methods. Results Flower extracts contained a high level of polyphenolics (17.10-52.70 mg GAE/g) and flavonoids (74.20-100.60 mg QE/g), which correlate with its appreciable antioxidant potential in β-carotene peroxidation (IC50 value: 12.50-27.10 μg/mL), DPPH(•) radical-scavenging (IC50 value: 0.20-0.40 mg/mL), Fe(3+ )reducing (EC50 value: 0.10-0.14 mg/mL) and Fe(2+ )chelating (IC50 value: 0.20-0.60 mg/mL) assays. These extracts were effective in inhibiting cancer cell growth (IC50 value: 62.0-63.25 μg/mL). Besides, the ethyl acetate extract inhibited phospholipase A2 activity (IC50 value: 2.97 mg/mL) and reduced the paw oedema in mice (from 0.38 ± 0.01 to 0.24 ± 0.01 cm), 4 h post-carrageenan challenge. Conclusion These data suggest that D. simplex may be useful as a candidate in the treatment of inflammation and the colon cancer. more...

Jujube (Ziziphus lotus L.) fruit has multiple functional properties and represents an interesting source of bioactive compounds. The purpose of this study was to improve the functionality and the sensory properties of sponge cake enriched with Z. lotus fruit. The polyphenols and flavonoids levels in the sponge cake and its antioxidant potential increased with the addition of 0-10 g of jujube powder/100 g of wheat flour. The crumb color parameters, L* and b*, decreased with the addition of jujube powder, whereas the a* value increased. In the texture analysis, addition of jujube powder resulted in an increase of the hardness and chewiness, but the springiness was reduced. The sensory evaluation showed that supplementation of jujube powder did not manifest any undesirable organoleptic response and showed satisfactory consumer acceptability. Overall, the addition at 5% jujube powder showed the finest sensory properties of the sponge cake. more...

Allium roseum leaves were subjected to thin layer convective drying at three temperatures (40, 50 and 60C) and two air velocities (1.0 and 1.5 m/s). The effects of the drying conditions on drying characteristics, color, phenolic compounds and antioxidant properties of A. roseum leaves were assessed. Convective drying induces a considerable moisture removal from fresh leaves (more than 96%) and requires 7 and 28 h at 60 and 40C, respectively. Fresh A. roseum leaves have a water activity higher than 0.9, which had been reduced after drying to a value of about 0.5. Drying resulted in color modifications and drastic declines in total polyphenol content (between 60 and 69%), total flavonoid content (between 17 and 29%) and radical-scavenging capacity (between 72 and 88%). Drying temperature showed a significant effect on drying rate, moisture loss, water activity, total polyphenol content, total flavonoid content and radical-scavenging activity of A. roseum leaves. Practical Applications Allium roseum, also known as rosy garlic, and called in Tunisia “Lazoul,” is a spontaneous plant that grows in the southern part of the country during the rainy years. Local indigenous communities traditionally use Lazoul leaves as a condiment in various meals. The specific taste attributed to these leaves is highly appreciated, but moreover their therapeutic properties, due to antibacterial, antifungal and antioxidant activities, are now well known. However, the short vegetative presence of Lazoul limits its availability and renders it rare. Traditional food prepared with fresh A. roseum leaves tend to disappear, and thus, preparation of such foods, which has been inherited from one generation to the other within a traditional knowledge, is now threatened. Drying may be a solution for A. roseum preservation throughout the year. Moreover, bringing small-scale technologies to local people may revitalize biodiversity and protect traditional food from disappearance. more...

Allium roseum L., a North African endemic species, is a rich source of many important nutrients and bioactive compounds responsible for many promising beneficial health physiological effects. The influence of sulfur fertilization (S fertilization) on the flavor, total polyphenols, and carbohydrates content in A. roseum was studied, using three sulfur concentrations (0.01, 1.50 and 4.50 mmol L−1) under controlled conditions. S fertilization showed a significant increase in the allicin concentration of A. roseum bulbs with an average of 0.859–2.285 g kg−1 FW for bulbs grown at 0.01 and 1.50 mmol L−1 SO42−, respectively. The same trend was observed for total polyphenol content. On the contrary, the highest level of S decreased the content of reduced carbohydrates. These results provide evidence that the concentrations of allicin and polyphenols in A. roseum are increased by S fertilization, potentially amplifying its beneficial impacts on health. more...

International audience; Use of plant extracts, alone or combined to the current chemotherapy as chemosensitizers, has emerged as a promising strategy to overcome tumor drug resistance. Here, we investigated the anticancer activity of Allium roseum L. extracts, a wild edible species in North Africa, on human Chronic Myeloid Leukemia (CML) K562 cells. The dehydrated aqueous extract (DAE) disturbed the cell cycle progression and induced the apoptosis of K562 cells. Chemical analysis of DAE showed a diversity of organosulfur compounds S-alk(en)yl-cysteine sulfoxides (RCSO) and high amount of allicin, suggesting that such molecule may be behind its antitumor effect. DAE was efficient in inhibiting K562 cell viability. DAE inhibitory effect was associated with the dephosphorylation of the BCR-ABL kinase and interfered with ERK1/2, Akt, and STAT5 pathways. Furthermore, we found that DAE-induced inactivation of Akt kinase led to the activation of its target FOXO3 transcription factor, enhancing the expression of FOXO3-regulated proapoptotic effectors, Bim and Bax, and cell cycle inhibitor p27. Finally, we found that DAE reduced the secretion of vascular endothelial growth factor. Overall, our data suggest that A. roseum extract has great potential as a nontoxic cheap and effective alternative to conventional chemotherapy more...

Allium is the largest and the most important representative genus of the Alliaceae family. For many centuries, several Allium species have been used as vegetables and spices, and as folk medicines for curing various diseases. Besides the well-known garlic and onion, other species are either, widely cultivated for culinary use, such as leek, scallion, shallot and chive, or found as wild endemic species grown spontaneously. more...

This study deals with the chemical characterization of a medicinal and an aromatic plant of the Tunisian flora: Allium roseum var. odoratissimum, and aimed to identify new bioactive natural compounds in its flower essential oil. These compounds were extracted by hydrodistillation and were analyzed by GC and GC/MS, using an apolar column. The most important compounds characterized were organo-sulphurous (46%), including methyl 2-propenyl trisulfide, di-2-propenyl trisulfide, di-1-propenyl disulfide, di-2-propenyl disulfide, dimethyl trisulfide, methyl 2-propenyl disulfide, and di-1-propenyl trisulfide, found as 10.75, 9.07, 5.81, 4.98, 3.90, 3.30, and 2.53%, respectively. Moreover, heneicosane and pentacosane were identified for the first time at relatively high rates (8.18 and 4.49%, respectively) in the Allium roseum essential oil. This essential oil composition exhibited newly identified sulphurous compounds at relatively high rates (46.53%) when compared with what was found while using polar column. more...

Allium roseum L. var. odoratissimum, a North African endemic species, grows in the Southeast of Tunisia and is used as a vegetable, spice or herbal remedy in traditional medicine. This study deals with the phytochemical analyses and antimicrobial activity screening of A. roseum leaves. Aqueous extracts (maceration, digestion, decoction and infusion) and organic extracts (petroleum ether, dichloromethane, methanol and ethanol) were screened for their phytochemical antibacterial activity. Phytochemical screening of A. roseum showed the presence of antimicrobial active compounds such as saponins, tannins, flavonoids, coumarins, steroids, cardiotonic glycosides, free quinone and iridoids. The dichloromethane, petroleum ether and ethanolic extracts of A. roseum exhibited a wide spectrum of antimicrobial activities against Staphylococcus aureus, Staphylococcus epidermidis, Micrococcus luteus, Escherichia coli and Pseudomonas aeruginosa. Such results may establish a good support to the use of this plant in herbal medicine and a base for the development of new drugs and phytomedicine. PRACTICAL APPLICATIONS Allium roseum var. odoratissimum (Desf.) Coss is widely used as a vegetable, spice and herbal remedy. Besides its culinary use, A. roseum is also used in folk medicine for the treatment of headaches, rheumatism, respiratory tract infection and low appetite. In this article, we validate the use of this species through the chemical constituents (saponins, tannins, flavonoids, coumarins, steroids, cardiotonic glycosides, free quinones and iridoids), which are responsible for the pharmacological properties mentioned earlier, particularly the antibacterial activity. For example, A. roseum exhibits a wide spectrum of antimicrobial activities against Staphylococcus aureus, Staphylococcus epidermidis, Micrococcus luteus, Escherichia coli and Pseudomonas aeruginosa. more...

Total polyphenolic contents (TPC), antioxidant and antibacterial activities of bulb, leaf and flower extracts of the North African endemic plant Allium roseum were studied using three different solvents. Flower and leaf TPCs were found significantly higher than that of bulb with the highest values in methanolic extracts reaching 736.65 ± 88.67 and 749.54 ± 129.15 mg catechol equivalent/100 g of dry material, respectively. The same trend was observed for antioxidant potentials using DPPH. and ABTS.+ scavenging methods. Moreover, the A. roseum phenolic extracts strongly inhibited the growth of a range of microorganisms. Multivariate analysis showed that the extraction solvent and the plant material significantly affected the quantity and bioactivity of the phenolics. Almost all extracts exhibited antioxidant and antibacterial activity; however, the highest values were found in the methanolic extracts of leaves and flowers. These results provide the basis for the use of this edible spontaneous species for fu... more...

This study deals with the valorisation of medicinal and aromatic Allium to find new bioactive natural products. The phytochemical analyses of A. roseum and A. ampeloprasum powders and their aqueous and organic extracts are achieved. The results show that these species are characterized by the presence, among their components, of three precursors of organosulphurous volatile compounds. They are methiin, isoalliine and alliine in A. roseum and isoalliin and methiin in A. ampeloprasum. These differences in their flavours can correlated with the vicinity of A. roseum with garlic and A. ampeloprasum with onion. Phytochemical screening of Allium roseum shows the presence of active agents such as saponins, tannins, flavonoids, coumarins, steroids, cardiac glycosides, free quinone and iridoids. more...

This study was conceived to examine the antimicrobial and antioxidant activities of four essential oil types extracted by hydrodistillation from the aerial parts of Artemisia herba-alba cultivated in southern Tunisia. The chemical composition was investigated using both capillary GC and GC/MS techniques. β-thujone, α-thujone, α-thujone/β-thujone and 1,8-cineole/camphor/α-thujone/β-thujone were respectively, the major components of these oil types. The antimicrobial activity of different oils was tested using the diffusion method and by determining the inhibition zone. The results showed that all examined oil types had great potential of antimicrobial activity against strains. In addition, antioxidant capacity was assessed by different in vitro tests and weak activity was found for these A. herba-alba oils. more...

This study deals with the valorisation of medicinal and aromatic plants of the Tunisian flora, in order to find new bioactive natural products. The essential oil constituents from the flowers of Allium roseum var. odoratissimum, a North African endemic species growing in the south-east of Tunisia, were extracted by hydrodistillation and analysed by GC–MS. The most important compounds were sulphurous compounds (2,4-dimethylthiophene, 2-propenyl methyl disulfide, 1-propenyl methyl disulfide, dimethyl trisulfide, and 3-methyl-thiopropionaldehyde or methional). After an exhaustive literature review dealing with other varieties of the same species, it seems that the variety odoratissimum is the only taxon characterized by trisulfide and methional contents. Methional is of particular importance because it is found at high concentration (17%). The antibacterial activity of seven extracts was evaluated by the diffusion method and by determining the inhibition zone. All extracts exhibited an antibacterial activity at different levels against strains reported as the causal agents of food-borne diseases. Results suggest the potential use of the plant as condiment and preservative in the food industry. more...

The present study deals with the valorization of an edible spontaneous plant of the Tunisian arid areas: Allium roseum. This plant is traditionally used for therapeutic and culinary uses. Thin-layer drying behavior of Allium roseum leaves was investigated at 40, 50 and 60 °C drying air temperatures and 1 and l.5 m/s air velocity, in a convective dryer. The increase in air temperature significantly affected the moisture loss and reduced the drying time while air velocity was an insignificant factor during drying of Allium roseum leaves. Five models selected from the literature were found to satisfactorily describe drying kinetics of Allium roseum leaves for all tested drying conditions. Drying data were analyzed to obtain moisture diffusivity values. During the falling rate-drying period, moisture transfer from Allium roseum leaves was described by applying the Fick's diffusion model. Moisture diffusivity varied from 2.55 × 10(-12) to 8.83 × 10(-12) m(2)/s and increased with air temperature. Activation energy during convective drying was calculated using an exponential expression based on Arrhenius equation and ranged between 46.80 and 52.68 kJ/mol. All sulfur compounds detected in the fresh leaves were detected in the dried leaves. Convective air drying preserved the sulfur compounds potential formation. more...

Melanin performs a crucial role in protecting the skin against harmful ultraviolet light. However, hyperpigmentation may lead to aesthetic problems and disorders such as solar lentigines (SL), melasma, postinflammatory hyperpigmentation and even melanoma. Arthrophytum scoparium grows in the desert in the North African region, and given this type of environment, A. scoparium exhibits adaptations for storing water and produces useful bioactive factors. In this study, the effect of A. scoparium ethanol extract (ASEE) on melanogenesis regulation in B16 murine melanoma cells was investigated. Cells treated with 0.017% (w/v) ASEE showed a significant inhibition of melanin biosynthesis in a time-dependent manner without cytotoxicity. To clarify the mechanism behind the ASEE-treated melanogenesis regulation, the expressions of tyrosinase enzyme and melanogenesis-related genes were determined. Results showed that the expression of tyrosinase enzyme was significantly decreased and Tyr, Trp-1, Mitf and Mc1R mRNA expressions were significantly down-regulated. LC-ESI-TOF-MS analysis of the extract identified the presence of six phenolic compounds: coumaric acid, cinnamic acid, chrysoeriol, cyanidin, catechol and caffeoylquinic acid. The melanogenesis inhibitory effect of ASEE may therefore be attributed to its catechol and tetrahydroisoquinoline derivative content. We report here that ASEE can inhibit melanogenesis in a time-dependent manner by decreasing the tyrosinase protein and Tyr, Trp-1, Mitf and Mc1R mRNA expressions. This is the first report on the antimelanogenesis effect of A. scoparium and on its potential as a whitening agent. more...

Extracts of aerial parts and roots of wild Astragalus gombiformis Pomel were tested for their antibacterial, antioxidant, and insecticidal activities and contents of phenolic compounds. Antibacterial activity was tested by the paper disk agar diffusion method and determination of the minimal inhibitor concentration. Among the tested extracts, three extracts (methanol, chloroform, and ethyl acetate) from aerial parts and two extracts (water, methanol) from roots exhibited diameters of inhibition zone equal or above 12 mm (at 150 μg/ disk) and minimal inhibitor concentrations ranging between 233 and 1250 μg/ml. Spectrophotometric and HPLC analyses showed that contents of both total polyphenols and flavonoids, as well as antioxidant activity were higher in the methanolic extract of aerial parts as compared to roots. No insecticidal activity of the extracts of the aerial parts was found against Culex pipiens. more...