Objective: To evaluate the essential oil composition and the antibacterial activity of an\ud Algerian endemic plant, Launaea lanifera Pau (L. lanifera), grown in arid steppe regions.\ud Methods: L. lanifera essential oil was isolated from aerial parts by steam distillation and\ud its chemical composition was evaluated by gas chromatography-flame ionization detector\ud and gas chromatography with electron impact mass spectrometry. Furthermore, its\ud in vitro antibacterial activity against four bacterial strains was tested following the agar\ud disk diffusion method.\ud Results: This species had a very low essential oil yield (0.005%). Twenty-four (92.6%)\ud individual components were identified. The main constituents were hexahydrofarnesyl\ud acetone (31.6%), (E)-b-ionone (8.5%), (E)-b-damascenone (7.0%), 2-methyltetradecane\ud (3.8%), n-heptadecane (3.8%), limonene (2.8%) and b-caryophyllene (2.8%). No noteworthy\ud antimicrobial activity was observed on the tested bacteria, neither Gram negative\ud nor Gram positive.\ud Conclusions: This is the first report on the volatile constituents and antibacterial activity\ud of L. lanifera. The studied essential oil does not possess significant activity against the\ud tested microorganisms

This study represents the first investigation of the chemical composition and the antioxidant and antimicrobial activities of Ononis aurasiaca Förther & Podlech, a plant species endemic to the Aures Mountains of Algeria. The essential oil of the plant aerial parts was analysed using GC-MS. The in vitro antioxidant activity was evaluated using three methods. A total of 44 compounds were identified. The major constituents were dodecanal, hexahydrofarnesylacetone, 2-tridecanone, phytol, 1-heneicosene, and n-heneicosane. The oil displayed significant activity in the β-carotene bleaching assay, moderate scavenging activity against DPPH radicals and a low ability to reduce iron ions. Antibacterial tests conducted on four strains revealed effectiveness primarily against Gram-positive strains, specifically Staphylococcus aureus ATCC 25923 and ATCC 43300, while showing limited impact on Gram-negative strains, Pseudomonas aeruginosa ATCC 27853 and Escherichia coli ATCC 25922. Antifungal activity tests involving two moulds revealed a stronger inhibition against Scedosporium apiospermum compared to Aspergillus niger.

This study is the first to explore the essential oil of Ononis angustissima Lam. subsp. filifolia Murb., a subspecies growing in the Algerian northeastern Sahara. The chemical composition was evaluated by GC/GC-EIMS. Antioxidant activity was evaluated using two methods. Thirty-four (91.6%) individual components were identified. The main constituents were linalool (12.6%), hexahydrofarnesylacetone (8.4%), β-eudesmol (6.6%), α-cadinol (6.4%) and T-cadinol (6.1%). The findings provide a chemical basis for understanding relationships between North African subspecies, supporting botanical and genetic classification. The oil exhibited moderate scavenging activity against DPPH radicals (IC₅₀ = 102.30 µg/ml) and high activity in the β-carotene bleaching assay (91.346%). Antimicrobial tests revealed effectiveness against Gram-positive bacteria (Staphylococcus aureus ATCC 25923 and ATCC 43300), limited impact on Gram-negative bacteria (Pseudomonas aeruginosa ATCC 27853 and Escherichia coli ATCC 25922), and good inhibition against Aspergillus niger and Scedosporium apiospermum. A notable larvicidal activity was observed against Date Moth, particularly on L2 larvae.

Background: Over the past decade, most antibiotic research programs have focused on finding new compounds with antimicrobial activity. This study aims to investigate the chemical composition and antibacterial activity of the essential oil (EO) extracted from ripe berries of Algerian Juniperus thurifera var. aurasiaca. Methods: The chemical composition of J. thurifera EO extracted by hydrodistillation was analyzed by using the GC-MS technique. Antibacterial activity of EO alone and in combination with three conventional antibiotics was assessed by using disc diffusion method against four bacterial strains. Results: Thirty-five components were identified, representing ~87 % of the oil. The main components were m-mentha-6,8-diene (15.43 %), β-pinene (10.59 %), elemol (8.31 %) and terpinene-4-ol (7.44 %). The essential oil showed strong antibacterial activity against S. aureus and E. coli, but no activity against P. aeruginosa and B. subtilis. Synergistic effects were observed because of the combined application of EO with gentamicin against all strains tested, and with amoxicillin against B. subtilis. Furthermore, the combination of EO/cefazolin demonstrated an additive effect against B. subtilis. In contrast, the combination of EO with amoxicillin and céfazoline revealed antagonistic effects against S. aureus, E. coli, and P. aeruginosa. Conclusion: This is the first report on the chemical composition and antibacterial activity of Algerian juniper berries’ essential oil. The results indicate that the studied EO may be a promising source of antibacterial compounds that could be useful for pharmaceutical applications especially in combination with conventional antibiotics.