Effect of Extraction Methods on Botanical Insecticide Activity

摘要

Supercritical fluid extraction (SFE) was used for isolation of volatile components from savory (Satureja hortensis L.) and thyme (Thymus vulgaris L.). Three types of extracts were prepared using the benefit of variable solvent power of supercritical carbon dioxide under different experimental conditions. Composition and product activities of the CO_2 extracts were compared with hydrodistillation (HD) and Soxhlet extraction. The composition of volatile compounds in the isolates was determined by gas chromatography, and the toxicity and antifeedant effects of the extracts on larvae of Colorado potato beetle (Leptinotarsa decemlineata) were evaluated. Strong insecticidal effects of all isolates against larvae were observed, but significant differences between the particular isolates and plants were found. The most effective isolates were the essentials oils which showed the lowest LD50. The efficiency of extracts of S. hortensis (SFE2 and SFE3) was comparable with that of hydrodistilate and higher than the efficiency of other extracts, while their extraction yield was by 73% higher than the yield of hydrodistillate.