Larvicidal effects and phytochemical evaluation of essential oils of Trachyspermum ammi and Ziziphora clinopodioides against larvae Anopheles stephensi

Introduction: The main purpose of this research was to evaluate larvicidal effects of two native medicinal plants in Iran including seeds of Ajwain (Trachyspermum ammi) and leaves and shoots of Blue Mint Bush (Ziziphora clinopodioides) against larvae of Anopheles stephensi. Their phytochemical compounds of essential oils were also determined using GC-MS method.Methods: The plants were collected from various regions of the country in the spring of ۲۰۱۳, and the aqueous essential oils were prepared using a Clevenger apparatus. The standard WHO method for anti-larval experiments against third and fourth instar larvae of A. stephensi was employed at the Biometric Laboratory next to the Culicidae Insectarium at the School of Public Health of Tehran University of Medical Sciences.Results: The LC۵۰s (lethal concentrations to kill ۵۰%) and LC۹۰s of the essential oils were ۱۴.۲۶ and ۳۹.۵۴ ppm T. ammi and ۱۸.۶۱ and ۴۸.۵۱ ppm for Z. clinopodioides. Phytochemical analysis of the essential oils of the tested plants revealed that thymol for T. ammi and pulegone for Z. clinopodioides had the highest percentage which were ۷۱.۹۸۹ and ۴۸.۶۰۹, respectively.Conclusion: Considering the results of this research, the effective compounds in these essential oils that had larvicidal properties might be used against malaria vectors.