Composition of Cyclotrichium niveum Essential Oil: Enantiomeric Separation of Pulegone and Repellent Activity Against the Lone Star Tick, and Yellow Fever Mosquito
Ticks and mosquitoes transmit pathogens that can cause serious and sometimes fatal diseases to humans and other animals. Chemical repellents are an important personal protection tool to protect humans and livestock from arthropod bites. Our research programs focuses on the discovery of naturally occurring insecticides and repellents that can be used to further reduce disease transmission risk to animals. The most widely used topical repellent is a synthetic compound, DEET (N,N-diethyl-m-toluamide). However, concerns over the safety of DEET lead to some user acceptability issues among repellent users. Consequently, there has been an increase in focus on alternative repellents from the natural sources. As part of our efforts to identify natural repellents, we investigated the essential oil of Cyclotrichium niveum (Boiss.) Manden. (Labiatae) as a repellent against the lone star tick, Amblyomma americanum nymphs, and against adult yellow fever mosquitoes, Aedes aegypti. Cyclotrichium niveum essential oil showed good repellent activity against both species and pulegone was more effective against A. americanum and Ae. aegypti. The enantiomeric distribution of (R)-(+)-pulegone was determined by using Rt-βDEXse fused silica chiral capillary column using multidimensional GC-MS system. Acknowledgements: This study was supported by USDA, ARS grant No. 56 – 6402 – 1-612 and Deployed War-Fighter Protection (DWFP) Research Program and the U.S. Department of Defense through the Armed Forces Pest Management Board (AFPMB).