Comparative repellency of 38 essential oils against mosquito bites

Abstract

The mosquito repellent activity of 38 essential oils from plants at three concentrations was screened against the mosquito Aedes aegypti under laboratory conditions using human subjects. On a volunteer's forearm, 0.1 mL of oil was applied per 30 cm2 of exposed skin. When the tested oils were applied at a 10% or 50% concentration, none of them prevented mosquito bites for as long as 2 h, but the undiluted oils of Cymbopogon nardus (citronella), Pogostemon cablin (patchuli), Syzygium aromaticum (clove) and Zanthoxylum limonella (Thai name: makaen) were the most effective and provided 2 h of complete repellency. From these initial results, three concentrations (10%, 50% and undiluted) of citronella, patchouli, clove and makaen were selected for repellency tests against Culex quinquefasciatus and Anopheles dirus. As expected, the undiluted oil showed the highest protection in each case. Clove oil gave the longest duration of 100% repellency (2-4 h) against all three species of mosquito.

Applications of molecular modeling in the design of new insect repellents targeting the odorant binding protein of Anopheles gambiae

“…Among the compounds with potential repellency, eugenyl acetate presented the best affinity to AgOBP 1 , even better than the DEET, the compound with the best repellency results reported in the literature. 16 Eugenol also looked promissing, considering that it presented the best results among the attractive compounds studied.…”

“…Products containing the clove oil in concentrations of 10 or 20% plus 10% of makaen (Limonella zanthoxylum) presented repellence against Aedes aegypti and Culex quinquefasciatus. 16 There is still no proposed mechanism to explain the repelency observed for the components of the indian clove oil but our group believes that these molecules are also able to bind to the AgOBP 1 binding site in the same way as DEET. So, docking and molecular dynamics (MD) techniques were employed to study the interactions between DEET and AgOBP 1 and to compare them to the interactions of this OBP with attractive molecules such as lactic acid, 1-octen-3-ol and indole 11 and the majoritary components of the indian clove oil: eugenol, eugenyl acetate, α-humulene and β-caryophyllene 3,17-21 ( Figure 1).…”

Repellent and mosquitocidal effects of leaf extracts of Clausena anisata against the Aedes aegypti mosquito (Diptera: Culicidae)

“…Undiluted citronella oil gives 100% protection from host-seeking mosquitoes for about two hours only and loses its activity thereafter (Trongtokit et al 2005). Another study reports of 20% citronella oil giving 75.7% protection against A. aegypti for 2 hours (Amer and Mehlhorn 2006).…”

Composição e fungitoxicidade do óleo essencial de capim citronela em função da adubação orgânica

“…Os óleos essenciais produzidos por C. nardus e C. citratus apresentam alto teor de geraniol e citronelal (Barbosa et al, 2008). O citronelal é utilizado como material básico para a síntese de importantes compostos químicos, denominados iononas, que são precursores e sintéticos para a obtenção de vitamina A. Esse óleo apresenta atividade repelente a insetos e ação fungicida e bactericida, além de ser utilizado na fabricação de perfumes e cosméticos (Trongtokit et al, 2005;Wong et al, 2005;Reis et al, 2006). O objetivo deste trabalho foi avaliar a influência da adubação orgânica sobre o teor e a composição do óleo essencial do capim citronela (Cymbopogon nardus), bem como a fungitoxicidade desse óleo ao crescimento micelial dos fungos Didymella bryoniae, Colletotrichum gloeosporioides e Amphobotrys ricini.…”