Electrophysiological and behavioral characterization of bioactive compounds of the Thymus vulgaris, Cymbopogon winterianus, Cuminum cyminum and Cinnamomum zeylanicum essential oils against XXXX and prospects for their use as bednet treatments.

@entity1 @entity137 @entity199 @entity3125 @entity312 @entity313
BACKGROUND: Laboratory and field studies showed that repellent, irritant and toxic actions of common public health insecticides reduce @entity1 -vector contact and thereby interrupt disease transmission. One of the more effective strategies to reduce disease risk involves the use of long-lasting treated bednets. However, development of insecticide resistance in mosquito populations makes it imperative to find alternatives to these insecticides. Our previous study identified four essential oils as alternatives to @entity312 : Thymus vulgaris, Cymbopogon winterianus, Cuminum cyminum, Cinnamomum zeylanicum. The objectives of this study were to identify active compounds of these essential oils, to characterize their biological activity, and to examine their potential as a treatment for bednets. METHODS: We evaluated the electrophysiological, behavioural (repellency, irritancy) and toxic effects of the major compounds of these oils against @entity313 'Kisumu'. RESULTS: @entity3125 elicited the strongest responses and @entity199 the weakest responses in electroantennogram (EAG) trials. However, EAG responses did not correlate consistently with results of behavioral assays. In behavioral and @entity137 studies, several of the single compounds did exhibit repellency, irritancy or @entity137 in An. gambiae; however, the activity of essential oils did not always correlate with activity expected from the major components. On the contrary, the biological activity of essential oils appeared complex, suggesting interactions between individual compounds and the insect under study. Data also indicated that the three effects appeared independent, suggesting that repellency mechanism(s) may differ from mechanisms of irritancy and @entity137 . CONCLUSIONS: Based on the bioassays reported here, some of the compounds merit consideration as alternative bednet treatments.
