Essential oil composition of eugenia langsdorffii O. Berg.: Relationships between some terpenoids and toxicity against tetranychus urticae

Abstract

Leaf and fruit essential oils of Eugenia langsdorffii were analyzed by GC-FID (gas chromatography with flame ionization detection) and GC-MS (gas chromatography with mass spectrometric detection), featuring a high percentage of sesquiterpenes. epi-Longipinanol (13.6 ± 0.1%) and γ-eudesmol (12.3 ± 0.2%) were the principal components of the leaf oil, whereas 10-epi-γ-eudesmol (35.7 ± 0.3%) and 1,10-di-epi-cubennol (15.6 ± 0.3%) were the major constituents of the fruit oil. A comparative study to assess fumigant and residual contact toxicities of the oils was conducted. The leaf oil (lethal concentration average, LC50 = 1.7 μL L -1 of air) was 1.7 times more toxic than the fruit oil and 1.8 times less toxic by residual contact. The positive control (eugenol) was much more toxic in the fumigation bioassay than Eugenia langsdorffii oils. Nevertheless, the residual contact effect of the fruit oil (LC50 = 12.25 μL mL-1) was just 6.7 times smaller than that of eugenol. The role of terpenoids in the acaricidal property of the E. langsdorffii essential oils was also discussed. © 2012 Sociedade Brasileira de Química.