Khaled Boufares - Department of Agricultures, Faculty of Science of Nature and Life Sciences, Ibn Khaldoun University, Tiaret Algeria.
Abdelkrim Hassani - Laboratory Agro-biotechnology and of nutrition in semi-arid zones (LANZA). Ibn Khaldoun University, Tiaret BP ۷۸ ۱۴۰۰۰, Algeria.
Aicha Somia Alem - Department of Agricultures, Faculty of Science of Nature and Life Sciences, Ibn Khaldoun University, Tiaret Algeria.

The objective of this work is to determine the chemical composition of essential oils of four Cupressaceae species and to bring out some of their antimicrobial activities. For this purpose, the extraction of essential oils was carried out by hydrodistillation and the obtained oils varied from ۰.۴% to ۰.۹۱%, with a better yield for Cupressus sempervirens equal to ۰.۹۱%. The chromatographic analyses revealed that the chemical composition of Juniperus phoenicea, Juniperus oxycedrus and C. sempervirens is largely dominated by monoterpenes at rates higher than ۳۴% with majority of α-pinene like component. In addition, the results of the antibacterial activity showed a significant inhibitory effect of essential oils, particularly those of J. phoenicea was found to be the most active with values of Minimum Inhibitory Concentration (MIC) equal to ۵۰μg/ml. Moreover, the mycelial growth inhibition confirms that essential oils of J. phoenicea and J. oxycedrus are most effective, with values of MIC equal to ۱۰۰۰μg/ml for both. These antimicrobial properties would be due to the richness of these essences in bioactive compounds such as the terpenoids, polyphenols and alkaloids known for their implication in the plants self-defense. Consequently, the inhibitory effect of these essential oils on the microbial development suggests prospects for their application as natural and safe alternatives to synthetic compounds for plant protection.

Biorational pesticides, Chromatography, Hydrodistillation, Pseudomonas, Fusarium