Larvicidal activities of some plants essential oils of the Cameroonian flora against Anopheles gambiae S.L., major vector of malaria in the city of Douala

Abstract

The present study aims to investigate the larvicidal activity of essential oils of the rhizomes of Zingiber officinalis, the leaves of Tithonia diversifolia and Bidens pilosa on the mature and immature larvae of Anopheles gambiae s.l. The chemical composition of the essential oils was determined by Gas Chromatography (GC) and Gas Chromatography and Mass Spectrometry (GC/MS) coupling. The larvicidal activities of essential oils against An. gambiae s.l. was monitored in the laboratory using the world health organisation protocol. Chemical analysis has shown that all these oils are dominated by monoterpene α-pinene was the major compound found in the essential oils of the leaves of T. diversifolia (69.53%) and B. pilosa (64.43%); while geranial was the majority compound found in the essential oil of Z. officinalis (35.40%). Larvicidal tests showed that the essential oil of the leaves of T. diversifolia was the most effective (LC50 = 70.18 ppm and 92.49 ppm respectively for larvae of immature and mature stages after 24 hours of exposure). From the above, the essential oil of the leaves of T. diversifolia can be recommended for the development of natural biocides against malaria vectors.