Mint species (Lamiaceae family) have been used as traditional remedies for the treatment of several diseases. In this work, we aimed to characterize the biological activities of the total phenolic and flavonoid contents of Mentha pulegium L. extracts collected from two different regions of Tunisia. The highest amounts of total phenols (74.45 ± 0.01 mg GAE/g DW), flavonoids (28.87 ± 0.02 mg RE/g DW), and condensed tannins (4.35 ± 0.02 mg CE/g DW) were found in the Bizerte locality. Methanolic leaf extracts were subjected to HPLC-UV analysis in order to identify and quantify the phenolic composition. This technique allowed us to identify seven phenolic compounds: two phenolic acids and five flavonoid compounds, such as eriocitrin, hesperidin, narirutin, luteolin, and isorhoifolin, which were found in both extracts with significant differences between samples collected from the different regions (p < 0.05). Furthermore, our results showed that the methanolic extract from leaves collected from Bizerte had the highest antioxidant activities (DPPH IC₅₀ value of 16.31 μg/mL and 570.08 μmol Fe²⁺/g, respectively). Both extracts showed high radical-scavenging activity as well as significant antimicrobial activity against eight tested bacteria. The highest antimicrobial activities were observed against Gram-positive bacteria with inhibition zone diameters and MIC values ranging between 19 and 32 mm and 40 and 160 µg/mL, respectively. Interestingly, at 10 μg/mL, the extract had a significant effect on cell proliferation of U87 human glioblastoma cells. These findings open perspectives for the use of Mentha pulegium L. extract in green pharmacy, alternative/complementary medicine, and natural preventive therapies for the development of effective antioxidant, antibacterial, and/or antitumoral drugs.

The present study aims to study the chemical composition of the essential oils from needles of three pine species: Pinus halepensis Mill., P. pinaster Aiton. and P. pinea L., and the evaluation of their in vitro anti-radical and antibacterial properties. GC-MS analysis showed that the essential oils were characterized by the abundance of monoterpene hydrocarbons (61.55-86.72 %). α-pinene, β-pinene, α-terpinolene, α-fenchene, and β-caryophyllene were the most plentiful components in P. halepensis. Limonene, α-pinene, and β-caryophyllene were particularly abundant in P. pinea and P. pinaster essential oils. The strongest DPPH-radical scavenging activity (IC₅₀ = 73.03 μg/mL) was observed for the limonene-rich essential oils of P. pinea. The three essential oils were effective against the Gram+ bacteria Bacillus subtilis and Listeria monocytogenes and the Gram- bacteria Salmonella enterica and Escherichia coli. These results suggest that P. halepensis, P. pinaster, and P. pinea could constitute a consolidated source of natural bioactive ingredients with anti-radical and antimicrobial properties.

In this study, the chemical composition and biological activities of the essential oil (EO) extracts (from leaves and cones) of the Tunisian Thuja occidentalis were evaluated. The composition of the leaf EO extract was more complex than that of the cones. The major components of the leaf EO extract were α-Pinene (34.4%), cedrol (13.17%), and β-Phellandrene (8.04%), while the composition of the cone EO extract was characterized by the predominance of α-Pinene (58.55%) and 3-Carene (24.08%). All EO extracts showed much better antioxidant activity than Trolox against 2, 2′-diphenyl-1-picryl hydrazyl (DPPH) radical scavenging, but EOs extracted from leaves exhibited the highest total antioxidant activity. All EOs showed strong antibacterial and antifungal activities against nine tested foodborne microorganisms (Bacillus cereus American Type Culture Collection (ATCC) 1247, Listeria monocytogenes ATCC 7644, Staphylococcus aureus ATCC 29213, Aeromonas hydrophila EI, Escherichia coli ATCC 8739, Pseudomonas aeruginosa ATCC 27853, Salmonella typhimurium NCTC 6017, Aspergillus flavus (foodborne isolate), and Aspergillus niger CTM 10099. The highest antimicrobial activities by disk diffusion assay were recorded for the EOs extracted from leaves, while no difference in potency was marked between leaf and cone EO extracts by the agar dilution method. The most potent antimicrobial activity was recorded among fungi. This study confirms the strong antimicrobial and antioxidant potential of EO extracts from the Tunisian T. occidentalis (from the Sidi Bou Said site), highlighting its potential as a natural preservative against foodborne pathogens, particularly against E. coli and S. typhimurium.

Eucalyptus marginata L. has a significant value in traditional medicine and recently has been shown to possess many pharmacological properties in vitro. The main goal of the present study was to optimize the extraction parameters of phenolic compounds from Eucalyptus marginata L. leaves using the extraction technique assisted by ultrasound in comparison with maceration using response surface methodology as a predicted tool. Therefore, total phenolic and flavonoid contents have been optimized, taking into account four variables: extraction time, temperature, liquid-to-solid ratio, and ethanol concentration. The optimum ultrasound-assisted extraction method for total phenolic and total flavonoid contents was obtained by ensuring the following parameters: t=49.9min, T=74.9°C, liquid-to-solid ratio=39.5ml/g, and ethanol=58.48. The optimum extract has been subjected to LC-ESI-MS analysis. This technique allowed us to identify ten phenolic compounds: four phenolic acids mainly gallic acid (27.77±0.06µg/g DW) and protocatechuic acid (37.66±0.04µg/g DW) and six flavonoid compounds such as quercetrin (150.78±0.02µg/g DW) and hyperoside (39.19±0.03µg/g DW). These green and efficient procedures should be a promising option to guide industrial design for the production of phenolic-rich plant extracts.

This study aimed to evaluate Pinus halepensis Mill. seeds oil as well as methanolic‐aqueous extract on fatty acid and phenolic's composition as well as antioxidant activities with regard to the cones drying methods: convection and sun methods. The highest amounts of total phenols (14.63 ± 0.05 mg GAE/g DW), flavonoids (3.3 ± 0.02 mg QE/g DW), and condensed tannins (0.36 ± 0.05 mg CE/g DW) were showed in the seeds obtained by sun‐dried method. Methanolic‐aqueous seeds extracts were subjected to LC‐ESI‐MS analysis in order to identify and quantify the phenolic composition. This technique allowed us to identify eleven phenolic compounds: two phenolic acids and nine flavonoid compounds such as cirsiliol, catechin (+), luteolin, and luteolin‐7‐O‐glucoside, which were present in the two studied samples while apigenin, naringenin, and cirsilineol were only identified in the extract obtained from sun‐drying method seeds. The chemical components of the oils were analyzed using GC, and significant differences were found between the two studied seeds oil (p < .05). Furthermore, the antioxidant activities were investigated using DPPH and ABTS.⁺ assays. The results showed that the methanolic‐aqueous extract from seeds dried by sun method had the highest antioxidant activities (0.08 and 0.05 mg/ml, respectively). This study could provide useful information for industry to produce potentially bioactive plant extract.

The characterization of the drought stress responses of plants is essential to understand the interactions of these effects with key life processes, such as growth and reproduction. The capability of plants to respond to abiotic stress is associated with their plasticity as well as the adaptableness of plant traits to fluctuating bioclimatic conditions. In this study, the response of Pinus halepensis seedlings to the different water irrigation regimes was assessed based on various ecophysiological, biochemical, and metabolic traits. This approach aims to identify different traits capable of predicting the ability of formerly uncharacterized seedlings to cope with drought stress. The obtained results revealed that drought stress affects the vital metabolic processes in Aleppo pine plants, such as transpiration, photosynthesis, and respiration at their early development stage. These variations were accompanied by changes in chlorophyll pigment contents and an accumulation of organic solutes (sugar and proline). Both drought stress levels induced an increase over the control of the amounts of total secondary metabolites and essential oil contents. These findings are of particular interest in the comprehension of seedlings response to drought stress which provides valuable background knowledge for the success of reforestation programs based on this woody species.