No abstract

Two Algerian origin oils of Mentha rotundifolia (L.) H ud. were analyzed by means of GC and GC/M S. Piperitenone oxide (23.5-38.6%) and cis-piperitone oxide (28.1-30.5%) were the two main constituents of the oils analyzed.

The aim of the present study was to determine the chemical composition and evaluate the acaricidal activity of Thymus algeriensis essential oil (TAEO) against Varroa destructor. This ectoparasitic mite is a pest of the honey bee Apis mellifera. The essential oil from the aerial parts of T. algeriensis, obtained by hydrodistillation, was obtained in a yield of 2.8± 0.2%, w/w. The TAEO was analyzed by GC and GC/MS. Thirty-four compounds were identified, representing 99.3% of the oil. The main constituents were carvacrol (48.4%), γ-terpinene (14.9%), p-cymene (14.7%), and thymol (5.6%). Four lots were constituted at the level of an apiary in order to study the dynamics of the Varroa destructor and its host, Apis mellifera. After diagnosis by the biological method "install of diapers", the lots were treated at different doses of TAEO (0.1, 0.3 and 0.5%). TAEO was sprayed on top of the hives. The results show that TAEO at 0.5% resulted in a decrease in the rate of infestation of Varroa destructor, causing a mortality rate of 32.6% without negative effect on the nesting of the queen. The essential oil of T. algeriensis could be used as a bioacaricidal agent.

Myrtus communis L. essential oils were obtained by hydrodistillation, and the yields were 0.3% (w/w) and 0.1% for leaves and berries, respectively. Using gas chromatography (GC) and gas chromatography/mass spectometry (GC/MS), 25 components were identified in berry oil representing 89.5% of the oil composition. Linalool was the major compound in berry oil (36.2%) followed by estragole (18.4%) and 1,8-cineole (11.4%). Leaf oil was composed of 28 compounds representing 95.4% of the total composition of the oil. a-pinene was the major constituent of leaf oil at a concentration of (46.9%), followed by 1,8-cineole (25.2%). The two Algerian oils were characterized by the lack of myrtenyl acetate.

Myrtus communis L. leaf essential oils from Algeria were analyzed by gas chromatography (GC) and gas chromatography/mass spectrometry (GC/MS). A total of thirty-four components were identified accounting for 95% of the oil. The main compounds were limonene (23.4%), linalool (15.4%), geranyl acetate (10.9%), α-pinene (10.7%), linalyl acetate (8.2%) and 1,8-cineole (6.6%).The antimicrobial evaluation showed that myrtle oil exhibited good antibacterial activity against Staphylococcus aureus, Proteus mirabilis and Kleibsiella pneumonia, but differed according to the strains. Conversely, it was not active against Pseudomonas aeruginosa.