Chemical composition of Tagetes patula essential oil and its bioactivity against Aedes aegypti

Mosquitoes are vectors for many pathogens that cause human diseases like dengue fever, yellow fever and malaria. Currently, research at the National Center for Natural Products Research, University of Mississippi is focused on identification and development of natural products as repellents. In an effort to discover new plant based products, leaf essential oil from Tagetes patula L. (Asteraceae) was screened for biting deterrent activity against yellow fever mosquito, Aedes aegypti. Tagetes patula essential oil showed good biting deterrent activity against female Ae. aegypti. The leaf essential oil was analyzed by GC-FID and GC-MS and the main constituents were characterized as caryophyllene oxide 18.4%, β-caryophyllene 18.0%, spathulenol 9.1%, neophytadiene isomer-I 4.7%, heneicosane 3.8%. Bioassay-guided fractionation of T. patula leaf oil was further performed by using high performance flash chromatography system into 25 sub-fractions which were pooled together according to their TLC and GC-MS profile to give a total of four fractions (Fr I-IV). Out of these four fractions Fr III and Fr IV showed biting deterrent activity similar to DEET (N, N-diethyl-m-methylbenzamide). In this study, GC-FID and GC-MS systems were used to identify the active components in Fr III and Fr IV. Data on the biting deterrent activity of these fractions and pure compounds against Ae. aegypti will be presented.