The larvicidal activities of extracts of three hardwood species (Hymenaea stigonorcapa, Anadenanthera colubrina and Bowdichia virgilioides) against 4th instar larvae of Aedes aegypti were evaluated using WHO guidelines. Extracts of H. stignocarpa and A. colubrina showed weak activity. The highest larvicidal effect was obtained with the cyclohexane extract of the heartwood of B. virgilioides, which caused 100% mortality at concentrations at 50 and 100 µg/mL. Fraction toluene/EtOAc (8:2) from this extract showed larvicidal activity (LC₅₀ = 34.90 ± 1.27 µg/mL). A mixture of two compounds identified as medicarpin and maackiain exhibited a very good larvicidal activity (sub-fraction 2, LC₅₀ = 17.5 ± 1.87 µg/mL) and maackiain showed to be a strong larvicidal compound (LC₅₀ = 21.95 ± 1.34 µg/mL). This result can be of value in the search for new natural larvicidal compounds from other hardwood plant extracts and presents the first report of B. virgilioides being used to control a mosquito vector.
Keywords: Aedes aegypti; Bowdichia virgilioides; Hardwood; Maackiain; Medicarpin.
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