Larvicidal evaluation of three Mentha species essential oils and their isolated major components against the West Nile virus mosquito

Abstract

Summary The larvicidal activity of essential oils derived from three diff erent Mentha species (Lamiaceae) as well as their major aroma p-menthane type components were evaluated against Culex pipiens (Diptera: Culicidae). Therefore, pulegone, piperitenone, piperitone, carvone, menthone and menthol were isolated using column chromatography. The LC 50 values revealed that M. pulegium and M. piperita oils were the most toxic (46.97 and 40.28 mgl-1 respectively) and pulegone was the most eff ective (27.23 mgl-1 ) among the major ingredients. The activity of all essential oils is in agreement with the proportion/toxicity rate of their individual major components, apart from the case of M. piperita where the LC 50 values of its major ingredients menthone and menthol stand higher than 100 mgl -1 . For the isolated molecules, studies on structure activity relationships revealed that the location of C-C double bond and the presence of the isopropylidene group might be key factors. Additional keywords: Culex pipiens, essential oil, larvicidal activity, major components isolation, Mentha species