Amyris and Siam-wood Essential Oils: Insect Activity of Sesquiterpenes

Abstract

Recent investigations on the sesquiterpene-rich Amyris (Amyris balsamifera L.) and Siam-wood (Fokienia hodginsii L.) essential oils revealed significant arthropod repellency and toxicity responses. Amyris essential oil and one of its major components, elemol, were evaluated in laboratory bioassays and identified as effective mosquito repellents, specifically characterized by high levels of contact and minimal spatial repellency. Mosquito responses to catnip (Nepeta cataria L.) essential oil are characterized with high spatial activity, but lack significant contact repellency. Sampling within the staticair bioassay chamber with solid-phase microextraction provided measurements of the relative concentration and distribution of volatiles. These results supported the differences observed in repellency between essential oil treatments. Essential oil mixtures containing both spatial (catnip) and contact (Amyris) repellents were made and showed high levels of residual control via both modes of action. Siam-wood essential oil scored high in both spatial and contact efficacy against mosquitoes. Observations during this study included signs of toxicity. Two of the primary components of Siam-wood essential oil were tested for 24-hour house fly (Musca domestica L.) topical mortality. Transnerolidol and fokienol were found to possess similar insecticidal activity (topical LD50 values ranged from 0.17-0.21 µmol/fly). Amyris essential oil was selected for additional testing with brown dog ticks (Rhipicephalus sanguineusLatreille) in a 'barrier' repellency assay. Individuals were observed repeatedly avoiding and moving away from surfaces treated with Amyris essential oil. RightsWorks produced by employees of the U.S. Government as part of their official duties are not copyrighted within the U.S. The content of this document is not copyrighted. Recent investigations on the sesquiterpene-rich Amyris (Amyris balsamifera L.) and Siam-wood (Fokienia hodginsii L.) essential oils revealed significant arthropod repellency and toxicity responses. Amyris essential oil and one of its major components, elemol, were evaluated in laboratory bioassays and identified as effective mosquito repellents, specifically characterized by high levels of contact and minimal spatial repellency. Mosquito responses to catnip (Nepeta cataria L.) essential oil are characterized with high spatial activity, but lack significant contact repellency. Sampling within the staticair bioassay chamber with solid-phase microextraction provided measurements of the relative concentration and distribution of volatiles.These results supported the differences observed in repellency between essential oil treatments. Essential oil mixtures containing both spatial (catnip) and contact (Amyris) repellents were made and showed high levels of residual control via both modes of action. Siam-wood essential oil scored high in both spatial and contact efficacy against mosquitoes. Observations during this study included signs of toxicity. Two of the primary components of Siam...

Evaluation of Drimys winteri (Canelo) Essential Oil as Insecticide against Acanthoscelides obtectus (Coleoptera: Bruchidae) and Aegorhinus superciliosus (Coleoptera: Curculionidae)

“…Here, the CEO is characterized by the presence of 6 main compounds and the insecticidal activity in some of them was reported. The sesquiterpene elemol was reported for its toxicity against Drosophila melanogaster (Meigen) (Diptera: Drosophilidae) [ 66 ] and as a repellent against Aedes aegypti (L.) (Diptera: Culicidae) [ 67 , 68 ]. In addition, recent studies have shown that different EOs having elemol in their composition were repellent, fumigant and toxic against Tribolium castaneum (Herbst) (Coleoptera: Tenebrionidae) [ 69 ], insecticidal against Drosophila suzukii (Matsumura) (Diptera: Drosophilidae) [ 70 ] and Sitophilus granarius (L.) (Coleoptera: Curculionidae) [ 71 ] and inhibited the development of C. maculatus [ 72 ].…”

Essential Oils’ Chemical Characterization and Investigation of Some Biological Activities: A Critical Review

“…Moreover, it is well known that monoterpenes in the essential oils have phytotoxic effects that may cause anatomical and physiological changes in plant seedlings leading to accumulation of lipid globules in the cytoplasm, reduction in some organelles such as mitochondria, possibly due to inhibition of DNA synthesis or disruption of membranes surrounding mitochondria and nuclei [ 110 , 111 ]. Since the continued use of synthetic herbicides may threaten sustainable agricultural production and result in serious ecological and environmental problems, essential oils with allelopatic properties could be exploited as in alternative strategies leading to the development of biodegradable and non-toxic compounds [ 112 ].…”

Mosquito repellents: a review of chemical structure diversity and olfaction

“…Evidence of optimization and formulation of these plant essential oils can be seen in the current scientific and patent literature, including synergistic effects identified by EcoSMART Technologies (US Patent 7,238,726). The structural activity of other terpenes still remains an area for development of new repellents, in particular the sesquiterpenes 106, 107…”