Biological activities of four essential oils against <i>Anopheles gambiae</i> in Burkina Faso and their <i>in vitro</i> inhibition of acetylcholinesterase

Abstract

The control of malaria is still a challenge partly due to mosquito’s resistance to current available insecticides. The aim of this work was to evaluate the ovicidal, larvicidal and repellent activities of Lantana camara, Hyptis suaveolens, Hyptis spicigera and Ocimum canum essential oils against  Anopheles gambiae s.l.  according to the World Health Organization standard method. The in vitro acetylcholinesterase inhibition activity of these oils was also evaluated. The repellent effect using the method of “separated arms” was evaluated. Lantana camara oil was more effective on both eggs and larvae. The LD₅₀ and LD₉₀ values observed in this oil solution were respectively 53.59 and 170.89 ppm on eggs whereas LD₅₀ and LD₉₀ were 61 and 125 ppm respectively on larvae. All oils exhibited repellent activities against adult mosquitoes. The most effective repellent was the oil of Hyptis suaveolens with a 50% efficacy dose value of 67 ppm. The highest  cetylcholinesterase inhibitory activity was observed with O. canum and H. suaveolens essential oils which IC₅₀ was 0.21 and 0.55 μg/ml respectively. Results suggest that these essential oils have a potential for vector control and can be considered as a source of natural and ecofriendly substances for malaria vector control.

Keywords: Anopheles gambiae s.l., malaria, essential oil, acetylcholinesterase, insecticidal activity.