Artemisia absinthium -borne compounds as novel larvicides: effectiveness against six mosquito vectors and acute toxicity on non-target aquatic organisms

Abstract

The eco-friendly control of mosquito vectors is a crucial challenge of public health importance. Here we evaluated the larvicidal potential of Artemisia absinthium essential oil (EO) and its three major chemical constituents against six mosquito vectors: Anopheles stephensi, Anopheles subpictus, Aedes aegypti, Aedes albopictus, Culex quinquefasciatus, and Culex tritaeniorhynchus. The EO was obtained by leaf hydro-distillation. Its chemical composition was analyzed using gas chromatography-mass spectrometry. Major components were (E)-β-farnesene (31.6 %), (Z)-en-yn-dicycloether (11.12 %), and (Z)-β-ocimene (27.8 %). The EO was toxic effect against larval populations of An. stephensi, An. subpictus, Ae. aegypti, Ae. albopictus, Cx. quinquefasciatus, and Cx. tritaeniorhynchus, with LC₅₀ values of 41.85, 52.02, 46.33, 57.57, 50.57, and 62.16 μg/ml. (E)-β-farnesene, (Z)-en-yn-dicycloether, and (Z)-β-ocimene were highly effective on An. stephensi (LC₅₀ = 8.13, 16.24 and 25.84 μg/ml) followed by An. subpictus (LC₅₀ = 10.18, 20.99, and 30.86 μg/ml), Ae. aegypti (LC₅₀ = 8.83,17.66, and 28.35 μg/ml), Ae. albopictus (LC₅₀ = 11.38,23.47, and 33.72 μg/ml), Cx. quinquefasciatus (LC₅₀ = 9.66, 19.76, and 31.52 μg/ml), and Cx. tritaeniorhynchus (LC₅₀ = 12.51,25.88, and 37.13 μg/ml). Notably, the EO and its major compounds were safer to the non-target organisms Chironomous circumdatus, Anisops bouvieri and Gambusia affinis, with LC₅₀ values ranging from 207.22 to 4385 μg/ml. Overall, our results highlight that (E)-β-farnesene, (Z)-en-yn-dicycloether, and (Z)-β-ocimene from the A. absinthium EO represent promising eco-friendly larvicides against six key mosquito vectors with moderate toxicity against non-target organisms.

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