Effect of regional disparities and solvent variations on the phenolic composition, antioxidant activity, and antibacterial efficacy of Cupressus sempervirens extracts.

The ethyl acetate, ethanol, methanol, and water extracts of cypress from three Tunisian regions (Bizerte, Ben Arous, and Nabeul) were reported for their phenolic content, antioxidant, and antibacterial activities. Cypress extract had an important antiradical and antibacterial potential which was strongly related to the organoleptic quality of the extract which appeared strongly region dependent. The highest contents of polyphenols were obtained in the methanol extract at the region of Bizerte (315.75 mg GAE/g DW). Cupressuflavone was the major compound with high proportions in methanol extract of Bizerte (68%). Amentoflavone also constituted an important flavonoid compound presented in higher proportion in the ethyl acetate extract of Ben Arous (21.2%). For Gram-positive bacteria strains, Staphylococcus aureus was sensitive to the ethanol extract of Nabeul with IZ = 40 mm. This study suggests cypress as potential natural source of antioxidants and antibacterial agents.

Screening of antimicrobial and insecticidal properties of essential oils extracted from three Tunisian aromatic and medicinal plants.

The essential oils (EOs) of Coriandrum sativum, Carum carvi and Artemisia herba-alba have been screened for their insecticidal activity against Tribolium castaneum, Sitophilus oryzae and Lasioderma serricorne and for their antimicrobial activity against Gram (+), Gram (-) bacteria and against yeast strain. Artemisia herba-alba EO showed good insecticidal activity with 24-h against L. serricorne (LC50 = 29.7) and against T. castaneum (66.1 µg/mL) and antibacterial potentials against Staphyloccocus aureus (MIC = 0.125 mg/mL). The antimicrobial activities of C. carvi EO, rich in D-carvone (72.4%) and D-limonene (23.8%) were particularly remarkable, with LC50 of 27.9 µg/mL against L. serricorne. Similarly, coriander EO, with linalool (64.6%) as the major compound was selected for its antimicrobial activities (Candida albicans, MIC = 1 mg/mL). These findings demonstrated that the tested EOs could be used as a natural source of insecticidal and antimicrobial activity, which may have a variety of uses in the food and pharmaceutical sectors.

Phenolic constitutents, antioxidant and repellent activities of coriander (Coriandrum sativum L.) fruits using different solvent extracts.

The organic solvent extracts (hexane, chloroform, acetone, methanol and water) of coriander fruits were reported for their antioxidant and repellent activities. The methanol and acetone extracts revealed the highest antiradical activity as compared to the other solvent extracts. HPLC analysis revealed that phenolic acids were the major compounds in chloroform and acetone extracts, whereas flavonoids in methanol and water extracts. The methanol extract of coriander fruits exhibited the highest repellent effect against coleopteran insects. Additionally, the hexane extract of coriander fruits also exhibited potent repellent and toxic activities against rice weevil. It appeared that coriander fruit extract obtained with the apolar solvent had more repellent potential against Sitophilus oryzae as compared to Tribolium castaneum. For Lasioderma serricorne, the methanol extract of coriander fruits reduced in a very significant way the adults followed by the chloroform and hexane extracts.