RESUMO
Objective: To evaluate the insecticide, larvicidal and repellent activity of the essential oils from Callistemon viminalis, Melaleuca leucadendron, and Hyptis suaveolens against Chrysodeixis chalcites and to compare it with neem oil (Azadirachta indica). Methods: The essential oils of the leaves of these aromatiques plants were extracted by steam distillation and contacts tests were carried out. Results: Essential oils in ethanol from Callistemon viminalis showed a higher biological activity than the neem with 100% larval mortality at the concentration of 2 μg/mL for 6 h, 100% and 90% in ethanol from Melaleuca leucadendron and Hyptis suaveolens, respectively at the concentration of 4 μg/mL for 24 h. By inhalation, the essential oils from Melaleuca leucadendron and of Hyptis suaveolens were more effective with mortality rates of larvae 100% and 50% respectively at 2 μg/L air applied after 24 h. Nevertheless, the neem has shown to be a repulsive plant and anti-nutritional plant. A significant difference in the percentages of consumption between leaves treated with neem oil and the control samples was observed (Newman-Keuls test) except for Melaleuca leucadendron. Conclusions: The results of the study highlight remarkable biocide, properties of tested extracts, which provides important opportunities for the development of biopesticides.
RESUMO
Berries and branches essential oil of Juniperus phoenicea were obtained by electromagnetic induction heating assisted extraction and by hydrodistillation with a yield varied from (1.2 ± 0.3 to 2.4 ± 0.7%) and from (0.6 ± 0.1% to 1.1 ± 0.1%), respectively. forty eight compounds were identified representing (97.2 – 99.7%) of the oil. α-Pinene (40.3 – 67.8%) and δ-3-carene (13.5 – 26.8%) were the main compounds in berries and branches essential oils. Antioxidant activity was evaluated by three means: inhibition of 2, 2-diphenyl-1-picryl hydrazyl (DPPH) free radical, reducing power and β-Carotene/linoleic acid bleaching. The antioxidant activity of essential oils showed IC₅₀ ranging from 67.6 ± 1.02 µg/mL to 131.5 ± 0.8 µg/mL for berries and from 98 ± 1.25 µg/mL to 166.8 ± 0.29 µg/mL for the branches. Berries oil show more potent antioxidant activity compared to branches. This result is supported by the three methods investigated in this work.