First report on the chemical composition and the free radical scavenging and antimicrobial activities of the essential oil of Ononis aurasiaca, an endemic plant of Algeria.

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.