Tunisian Native Mentha pulegium L. Extracts: Phytochemical Composition and Biological Activities.

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.

Identification and quantification of phenolic and fatty acid profiles in Pinus halepensis mill. seeds by LC-ESI-MS and GC: Effect of drying methods on chemical composition.

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.

Phenolic content, antioxidant capacity and antimicrobial activity of leaf extracts from Pistacia atlantica.

The aim of this study was to investigate the secondary metabolites related to Pistacia atlantica Desf as well as their biological activities. Results show that using ethanol as a solvent exhibited the highest content of total phenolics and flavonoids (68.23 mg GAE g-1 of DW and 44 mg RE g-1 of DW), followed by aqueous one (20.07 mg GAE g-1 of DW and 15 mg RE g-1 of DW). Good correlation (Data not shown) was obtained between the DPPH radical-scavenging activities and total phenolics contents. Many similarities were observed between the results of the DPPH (IC50 = 32 and 200 µg mL-1) and ABTS (IC50 = 42 and 300 µg mL-1) assays. All tested extracts contained phenolic compounds exhibited an antimicrobial effect against Gram-positive and Gram-negative bacteria. Further, researches for identification and purification of phenolic compounds are required.

Fatty acids composition of Tunisian Ziziphus lotus L. (Desf.) fruits and variation in biological activities between leaf and fruit extracts.

This study was conceived to evaluate the essential fatty acids, secondary metabolites, antiradical and antimicrobial activities of unexploited Tunisian Ziziphus lotus L. The obtained results indicated that the major components of fatty acids were oleic acid (88.12%) and elaidic acid (7.88%). Leaves contained higher amount of total phenols, flavonoids and tannins than fruits, although both methanolic extracts had significant antioxidant activities. Significant correlations were observed between the total phenol or flavonoid contents in methanolic extracts and antioxidant activity estimated by using both 2,2'-diphenyl-1-picrylhydrazyl and 2,2'-azino-bis-3-ethylbenzothiazoline-6-sulfonic radical-scavenging methods. In addition, both methanolic extracts exhibited strong antibacterial and antifungal activities. The inhibition zone diameters and the minimal inhibition concentration values were in the range of 10-17 mm and 3.1-50 mg/mL, respectively.