Larvicidal activity of the methanolic extract of <i>Warburgia ugandensis</i> seed oil on <i>Aedes aegypti</i>

Abstract

Mosquito is a vector implicated with Vector-borne diseases such as malaria (Anopheles’ species) dengue (Aedes species) and west Nile  fever (Culex species). Kenya experiences mosquito-borne disease outbreaks with the recent ones being the dengue virus and  chikungunya disease outbreak that occurred along the coast of Kenya. Medicinal plants such as Warburgia ugandensis that possess  larvicidal activity, have major importance in the control of mosquito. This study investigated the larvicidal activity and phytochemical  screening of the methanolic extract from the seed’s oil of Warburgia ugandensis. Quasiexperimental research design was used as the  study design. The plant was identified and authenticated by a taxonomist. Mature fruits of Warburgia ugandensis were obtained from the  school of pharmacy’s botanical garden and seeds separated and washed. Seeds were air dried, and crushed. Half of the GSP was  used to extract seed oil while the other half was subjected to various phytochemical screening. Larvicidal activity of the plant extracts was evaluated according to the World Health Organization guidelines for laboratory and field testing of mosquito larvicides. The activity of the methanol plant extract was evaluated at 25, 50, 100, and 125 ppm to determine the LC₅₀ value. Permethrin was used as a positive control.  About 8.06% of the seed oil was extracted. The seed oil and the leaves had a characteristic odour, a bitter taste and pale yellow in  color. Alkaloids, fixed oils, tannins and phyto-sterols were abundantly present in the seed. Proteins and carbohydrates were  moderately present while saponins were slightly present. Bioassays on mosquito larvae indicated larvicidal activity of methanolic seed oil  extract of Warburgia ugandensis against Aedes aegypti at concentrations of 25, 50, 100, and 200 ppm. Seed oil of Warbugia ugandensis contains phytochemicals that possesses larvicidal activity against Aedes aegypti mosquito species.