Occurrence, origin and potential ecological risk of dissolved polycyclic aromatic hydrocarbons and organochlorines in surface waters of the Gulf of Gabès (Tunisia, Southern Mediterranean Sea).

We investigated the occurrence, origin, and potential ecological risk of dissolved polycyclic aromatic hydrocarbons (PAHs), polychlorinated biphenyl (PCBs) and organochlorine pesticides (OCPs) in 27 surface water samples collected from a highly anthropized and industrialized area in the Gulf of Gabès (Tunisia, Southern Mediterranean Sea) in October-November 2017. The results demonstrated a wide range of concentrations (ng L-1) with the following decreasing order: Æ©16 PAHs (17.6-71.2) > Æ©20 PCBs (2.9-33.7) > Æ©6 DDTs (1.1-12.1) > Æ©4 HCHs (1.1-14.8). Selected diagnostic ratios indicated a mixture of both pyrolytic and petrogenic sources of PAHs, with a predominance of petrogenic sources. PCB compositions showed distinct contamination signatures for tetra- to hepta-chlorinated PCBs, characteristic of contamination by commercial (Aroclor) PCB mixtures. The dominant OCP congeners were γ-HCH, 2,4'-DDD and 2,4'-DDE, reflecting past use of Lindane and DDTs in the study area. Agricultural, industrial and domestic activities, as well as atmospheric transport are identified as potential sources of PAHs, PCBs and OCPs in surface waters of the Gulf of Gabès. Toxic equivalents (TEQs) suggested a low carcinogenic potential for PAHs in seawater samples (mean of 0.14 ng TEQ L-1). Evaluation of risk coefficients revealed low risk for PAHs and PCBs, and moderate to severe risk for OCPs.

Effects of Juniperus phoenicea Hydroalcoholic Extract on Inflammatory Mediators and Oxidative Stress Markers in Carrageenan-Induced Paw Oedema in Mice.

Juniperus phoenicea (J. phoenicea) is a wild tree belonging to the Cupressaceae family, commonly used for the treatment of several disorders. This study aimed to evaluate the potential protective effects of J. phoenicea hydroethanolic extract (EtOH-H2OE) against oxidation, acute inflammation, and pain in mice models. For the purpose, chemical compounds of J. phoenicea EtOH-H2OE were also analyzed by GC-MS. The J. phoenicea EtOH-H2OE showed a potent antioxidant activity in vitro, thanks to its richness in phenolic and flavonoid compounds. Mice treated with EtOH-H2OE (100 mg/kg BW) showed reduced paw oedema formation and decreased malondialdehyde (MDA) content. The evaluation of antioxidant enzyme activities in paw oedema tissue after five hours of carrageenan induction showed a significant increase (P < 0.05). Inflammatory biomarkers explorations of J. phoenicea EtOH-H2OE-treated mice showed a restoration of the studied parameters to near-normal values. Furthermore, EtOH-H2OE of J. phoenicea produced a significant reduction of the number of abdominal writhes (P < 0.05) in a dose-dependent way. Phytochemical analysis of the J. phoenicea EtOH-H2OE by GC-MS showed the presence of hexadecanoic and stearic acids known as anti-inflammatory and analgesic compounds. Our investigation provided evidence that J. phoenicea EtOH-H2OE can effectively reduce the inflammation and pain in mice models.

Antioxidant, Hepatoprotective, and Antidepression Effects of Rumex tingitanus Extracts and Identification of a Novel Bioactive Compound.

Over the last few decades, Rumex species have been recognized as a promising source of new compounds with numerous pharmacological activities. Therefore, the antioxidant activity of Rumex tingitanus (R. tingitanus) leaves extracts was evaluated in vitro and then confirmed in vivo as well as the antidepressant-like and toxicological effects of the extracts. The ethyl acetate fraction (Rt EtOAcF) followed by hydroalcoholic extract (Rt EtOH-H2O) showed a remarkable in vitro antioxidant activity. The hydroalcoholic extract (Rt EtOH-H2O) showed significant hepatoprotective activity against carbon tetrachloride- (CCl4-) induced liver toxicity which is seen from inhibition of the malondialdehyde (MDA) accumulation and enhancement of the liver antioxidant enzymes activities. The Rt EtOH-H2O and Rt EtOAcF extracts were able to reduce the immobility time in mice and then elicited a significant antidepressant-like effect. The ethyl acetate fraction (Rt EtOAcF) was purified and resulted in the identification of a new antioxidant component called 4'-p-acetylcoumaroyl luteolin. The Rt EtOAcF and the 4'-p-acetylcoumaroyl luteolin revealed a strong antioxidant activity using DPPH test with IC50 of 11.7 ± 0.2 and 20.74 ± 0.6 µg/ml, respectively, and AAI of 3.39 and 1.92 better than that of BHT, used as control.

Seasonal Variation in Essential Oils Composition and the Biological and Pharmaceutical Protective Effects of Mentha longifolia Leaves Grown in Tunisia.

This research assessed the seasonal variation of the chemical composition and antibacterial and anticholinesterase activities of essential oils extracted from M. longifolia leaves. The leaves organic fractions were also investigated for their biological activities and pharmacological functions. The essential oil highest yield was recorded in the spring season. Pulegone (26.92%), 1.8 cineole (21.3 %), and L-menthone (10.66 %) were determined as its major compounds in the winter season. In the spring oil, the main components were pulegone (38.2 %) and oleic and palmitic acids (23.79 % and 15. 26 %, respectively). Oxygenated monoterpenes were predominant in the two analyzed samples. The tested oils and organic extracts exhibited promising antibacterial effects against all of the tested bacterial strains. Thanks to its richness in phenolic and flavonoid compounds, the ethyl acetate fraction (Ml EtOAcF) displayed the most active DPPH scavenging ability (IC50 =12.64 µg/ml) and an interesting ß-carotene bleaching inhibition (IC50 =34.75 µg/ml) making it a potential candidate for anti-inflammatory evaluation on rats. This evaluation evidenced that M. longifolia pretreated rats showed a marked decrease in paw oedema and inflammatory cells. Additionally, a remarkable acetylcholinesterase inhibitory activity of the Ml EtOAcF (IC50 = 12.3µg/ml) and essential oils were also observed suggesting their neuroprotective property against Alzheimer's disease. Moreover, it was found that its activity level was season dependent. Our investigation, therefore, clearly revealed the medicinal characteristics of M. longifolia leave indicating their potential uses for natural remedies.

Exploring the Urtica dioica Leaves Hemostatic and Wound-Healing Potential.

The present paper investigated the efficiency of Urtica dioica (U. dioica) on hemostatic and wound healing activities. U. dioica leaf extracts were evaluated for their antibacterial and antioxidant effects as well as their flavonoid and polyphenol content. The hydroethanolic extract (EtOH-H2OE), showing the most potent antibacterial and antioxidant activities in vitro, thanks to its flavonoid and polyphenol richness, was selected for hemostatic and wound healing evaluation. Twenty-four rats completing full-thickness wounds were split into four groups. The wounds were topically treated with saline solution, glycerol, "CICAFLORA," and U. dioica EtOH-H2OE (50 µL/mm2) until day 11. The wound healing effect was assessed by macroscopic, histological, and biochemical parameters. Rats treated with EtOH-H2OE showed fast wound closure (92.39%) compared to the control animals (60.91%) on the 11th day of wounding (P < 0.01). Histopathological and biochemical explorations showed full epidermal regeneration and an improvement of the hydroxyproline content in the U. dioica EtOH-H2OE treated rats. Analysis of fatty acids and sterols by GC-MS showed the presence of unsaturated fatty acids and a high concentration of lupeol known for their involvement in reepithelialization. These results prove the efficiency of U. dioica EtOH-H2OE in wound healing and supported its traditional use.

Lipopeptides from a novel Bacillus methylotrophicus 39b strain suppress Agrobacterium crown gall tumours on tomato plants.

BACKGROUND: This study aims to characterise the antibacterial activity of a novel Bacillus methylotrophicus strain named 39b against tumourigenic Agrobacterium tumefaciens C58 and B6 strains. It also aims to identify the compound that is responsible for its activity and to evaluate its efficiency to control crown gall disease in tomato plants. RESULTS: B. methylotrophicus strain 39b was found to stop the growth of phytopathogenic A. tumefaciens strains in in vitro experiments. Lipopeptides - surfactins, iturins and fengycins - were detected under various isoforms by mass spectrometry analysis of the methanolic extract. The active principle acting against Agrobacterium strains was isolated from TLC plates and identified by mass spectrometry as surfactin. The strain was effective in reducing the weight and the number of galls induced by A. tumefaciens strains on tomato plants. Total inhibition of gall formation was observed using the antibacterial compounds. CONCLUSION: B. methylotrophicus strain 39b exhibited antibacterial activity against phytopathogenic A. tumefaciens C58 and B6 both in vitro and in vivo. Lipopeptides are the main compounds that confer the biocontrol ability. This strain has the potential to be developed as a biological control agent for crown gall disease. © 2016 Society of Chemical Industry.

Olive (Olea europaea) leaf extract induces apoptosis and monocyte/macrophage differentiation in human chronic myelogenous leukemia K562 cells: insight into the underlying mechanism.

Differentiation therapy is an attractive approach aiming at reversing malignancy and reactivating endogenous differentiation programs in cancer cells. Olive leaf extract, known for its antioxidant activity, has been demonstrated to induce apoptosis in several cancer cells. However, its differentiation inducing properties and the mechanisms involved are still poorly understood. In this study, we investigated the effect of Chemlali Olive Leaf Extract (COLE) for its potential differentiation inducing effect on multipotent leukemia K562 cells. Results showed that COLE inhibits K562 cells proliferation and arrests the cell cycle at G0/G1, and then at G2/M phase over treatment time. Further analysis revealed that COLE induces apoptosis and differentiation of K562 cells toward the monocyte lineage. Microarray analysis was conducted to investigate the underlying mechanism of COLE differentiation inducing effect. The differentially expressed genes such as IFI16, EGR1, NFYA, FOXP1, CXCL2, CXCL3, and CXCL8 confirmed the commitment of K562 cells to the monocyte/macrophage lineage. Thus our results provide evidence that, in addition to apoptosis, induction of differentiation is one of the possible therapeutic effects of olive leaf in cancer cells.

Chemical composition and antimicrobial and allelopathic activity of Tunisian Conyza sumatrensis (Retz.) E.WALKER essential oils.

Conyza sumatrensis (Retz.) E.WALKER (Asteraceae) is a spontaneous annual herb, fairly widespread throughout Tunisia, which has rarely been studied or valued in any sector. Essential oils were obtained by hydrodistillation of different parts (flower heads, leaves, stems, and roots) of C. sumatrensis plants, which were collected in autumn (November 2007) at the flowering stage in the area of Monastir, Tunisia. In total, 98 compounds, representing 88.1-99.3% of the oil composition, were identified by GC-FID and GC/MS analyses. The root essential oil was distinguished by its high content in acetylenes (matricaria ester, 4; 74.3%), while those from flower heads and leaves were dominated by oxygenated sesquiterpenes (61.1 and 50.3%, resp.). The oils of C. sumatrensis from Tunisia belonged to a matricaria ester/caryophyllene oxide chemotype. All the oils were evaluated for antibacterial, antifungal, and allelopathic activities. The results indicate that the leaf oil exhibited significant in vitro antibacterial activity against Enterococcus faecalis, Staphylococcus aureus, and Proteus mirabilis and that the C. sumatrensis oils isolated from the aerial parts presented high mycelia-growth inhibition of Candida albicans and the filamentous fungi tested. Moreover, the essential oils of the different plant parts inhibited the shoot and root growth of Raphanus sativus (radish) seedlings. Indeed, the inhibition of the hypocotyl growth varied from 28.6 to 90.1% and that of the radicle from 42.3 to 96.2%.

Pleiotropic effects of the wheat dehydrin DHN-5 on stress responses in Arabidopsis.

We have previously reported that transgenic Arabidopsis plants overexpressing the wheat dehydrin DHN-5 show enhanced tolerance to osmotic stresses. In order to understand the mechanisms through which DHN-5 exerts this effect, we performed transcriptome profiling using the Affymetrix ATH1 microarray. Our data show an altered expression of 77 genes involved mainly in transcriptional regulation, cellular metabolism, stress tolerance and signaling. Among the up-regulated genes, we identified those which are known to be stress-related genes. Several late embryogenesis abundant (LEA) genes, ABA/stress-related genes (such as RD29B) and those involved in pathogen responses (PR genes) are among the most up-regulated genes. In addition, the MDHAR gene involved in the ascorbate biosynthetic pathway was also up-regulated. This up-regulation was correlated with higher ascorbate content in two dehydrin transgenic lines. In agreement with this result and as ascorbate is known to be an antioxidant, we found that both transgenic lines show enhanced tolerance to oxidative stress caused by H2O2. On the other hand, multiple types of transcription factors constitute the largest group of the down-regulated genes. Moreover, three members of the jasmonate-ZIM domain (JAZ) proteins which are negative regulators of jasmonate signaling were severely down-regulated. Interestingly, the dehydrin-overexpressing lines exhibit less sensitivity to jasmonate than wild-type plants and changes in regulation of jasmonate-responsive genes, in a manner similar to that in the jasmonate-insensitive jai3-1 mutant. Altogether, our data unravel the potential pleiotropic effects of DHN-5 on both abiotic and biotic stress responses in Arabidopsis.