Assessment of the Larvicidal Potential of the Leaf Extracts of Hyptis suaveolens Poit against Culex Mosquitoes

The larvicidal potential of the ethanolic and aqueous leaf extracts of Hyptis suaveolens Poit on the 4 th larval instar of laboratory-reared Culex spp at varying concentrations of 0.1ml, 0.2ml, 0.3ml, 0.4ml and 0.5ml for specified periods of 24hrs, 48hrs and 72hrs was evaluated in this study. Qualitative phytochemcial screening of the leaf extracts identified bioactive components like alkaloid, saponin, phenol, anthraquinone and flavonoid. The LC 50 and LC 90 values obtained indicate that the ethanolic leaf extracts of Hyptis spp had the greatest toxicity on the test organisms within 24hrs of exposure at median LC 50 value of 0.497 as against the LC 50 value of 0.637 by its aqueous extract. The relative median potency estimates indicate that within 24 hrs, the ethanolic Hyptis spp was 0.185 times more potent on the test organism than aqueous Hyptis spp. The result of this research, therefore, gives credence to the efficacy of botanicals like Hyptis suaveolens Poit as an eco-friendly alternative in Culex mosquito control. It is, therefore, recommended that quantitative phytochemical screening, application of column chromatography as well as thin layer chromatography be carried out on the extracts to isolate and purify phytochemicals with larvicidal potentiality.

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