Repellent effect of some essential oil from Ivorian ethnomedicinal plant against malaria vector, Anopheles gambiae (Giles, 1902)

Abstract

To address the resistance developed by mosquitoes to pyrethroids in sub-Saharan Africa in general and by Anopheles gambiae in Cote d'Ivoire in particular, it has become urgent to seek insecticides with novel modes of action. Plant extracts such as essential oils, which generally contain a high proportion of bioactive molecules with insecticidal properties, could be a promising avenue. One alternative to control is to find natural repellents to complement the use of impregnated mosquito nets as recommended by WHO to reduce contact between humans and the malaria vectors. This study was undertaken to identify the active compounds of some essential oils and to study their repellent effect against adults of An. gambiae under laboratory conditions. Their effects were compared to that of DEET used as a positive control. The most promising extracts were those from Cymbopogon citratus, Cymbopogon nardus and Lippia multiflora. The repellent effect varies from one EO to another and the behavioural response of adults was significantly influenced by the concentration of plant extracts. The most abundant compounds were acyclic or monocyclic mono terpenes. The use of plant repellent essential oils for the formulation of an anti-mosquito product for the control of the malaria vector as an alternative control method can thus be considered.