ISOLATION OF VOLATILES WITH INSECTICIDAL PROPERTIES FROM THE GENUS TAGETES (MARIGOLD)

The results of optimizing Soxhlet and Simultaneous Distillation-Extraction (SSDE) procedures for the isolation of natural insecticides from Tagetes erecta, Tagetes patula, and Tagetes minuta, members of the Compositae family, are presented. Extraction procedures were developed and validated that produced the extract with the highest degree of biocidal activity. The highest activity was obtained with extracts isolated by SSDE using methylene chloride. Initial work was carried out on a micro-SSDE. Preparative SSDE was used to provide large quantities of extracts for bioassays. Bioassays were used to govern optimization procedures using Aedes aegypti and Anopheles stephensi adults and larvae as target organisms. Tagetes minuta was determined to be the most active of the three species studied. Evaluation of activity and recovery versus extraction time was investigated. It was determined that an extraction time of ten hours resulted in the highest activity and over 90 % recovery of the oils. Finally, supercritical fluid extraction of the flowers with CO2 was compared to SSDE.