Toxicity of Mexican native plant extracts against larvae of Aedes aegypti(Diptera: Culicidae)

Objective: To evaluate five indigenous Mexican plants [Hippocratea excelsa, Hippocratea celastroides, Argemone mexicana(A. mexicana), Tagetes lucida, and Pseudosmodingium perniciosum(P. perniciosum)] toxicity against the fourth instar larvae of the dengue primary vector, Aedes aegypti(A. aegypti).Methods: Each plant part was treated successively with hexane, ethyl acetate, acetone, and methanol to extract potential active components of the plants against the dengue vector.Results: There was a range of toxicity at 24 or 48 h post-exposure for the different plant parts and organic solvent used(LC50 values ranged between 20 and 890 μg/mL). Extracts from seeds of A. mexicana(hexane washing with methanol and acetone) and stem-bark of P. perniciosum(hexane) showed highest toxicity to Ae. aegypti larvae at 48 h post-exposure(LC50 values were80, 50, and 20 μg/mL, respectively), thus making them potential candidates as biolarvicides.Efforts are on-going to characterize the bioactive components of the extracts, through chromatography, for their use as biological tools for the control of the primary dengue vector.Conclusions: A. mexicana and P. perniciosum are good candidates to combat the dengue vector, Ae. aegypti, as they were highly toxic to the larvae.