Vol. 6, Issue 4, Part A (2019)

Author(s): Nanga WM, Saotoing P and Nukenine NE

Abstract: Malaria disease is a serious public health problem in tropical regions and the use of botanical insecticides and repellent products can provide practical means of preventing this disease. Adulticidal and repellent effects of methanol extracts and essential oils of the leaves of Hyptis suaveolens and Lippia adoensis were evaluated on Anopheles gambiae. Adulticidal activity was tested using 1000 to 125 mg/bottle of methanol extracts and from 100 to 12.5 mg/bottle of essential oils following CDC method. Repellency test was performed with cream formulation containing 15% of both plants extracts or essential oils each and applied at 2, 4 and 8 mg/cm² for each extract and 1, 2 and 4 mg/cm² for each essential oil on dorsal hand of volunteers according to WHO (1996) method. In result, up to 93.33% mortality of An. gambiae was registered with methanol extracts and essential oils tested at 1000 and 100 mg/bottle, respectively. The LC₅₀ values recorded after 24 h post exposure were 139.6 and 178.3 mg/bottle for extracts, 3.22 and 6.15 mg/bottle for essential oils of H. suaveolens and L. adoensis, respectively. Total protection for up to 120 min without receiving bites was recorded with creams formulation applied at dose of 8.0 mg/cm2. With essential oil cream formulation of both plant applied at 4.0 mg/cm², no bites were received for at least 150 min. In results, methanol extracts and essential oils extracted from the leaves of these plants have the potential to be used as a natural source insecticide and repellent plant to control An. gambiae.

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