Larvicidal, adulticidal and oviposition-deterrent activities of essential oil from leaves of Algrizea minor Sobral, Faria & Proença (Myrtaceae) against Aedes aegypti L. (Diptera, Culicidae) Rockefeller strain

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The global arbovirus epidemic poses a significant public health problem. Aedes aegypti L. is the primary vector of viruses that cause dengue, yellow fever, Zika, and Chikungunya. Vector control strategies rely primarily on synthetic insecticides, but the resistance development and their non-selective toxicity raise serious concerns, prompting the search for natural alternatives. Therefore, this study reports the insecticidal and enzyme- and oviposition-modulating activities of Algrizea minor Sobral, Faria & Proença leaf essential oil (AmEO) against Ae. aegypti (Rockefeller strain). AmEO was extracted by hydrodistillation and analyzed for chemical composition by gas chromatography coupled with mass spectrometry (GC–MS) and for insecticidal activity on larvae and adults. The effects of AmEO on larval trypsin, amylase and acetylcholinesterase (AChE) activities were also determined. Finally, the oviposition-modulatory effects of AmEO were evaluated. Chemical characterization identified 22 compounds, highlighting β-eudesmol (20.93%), α-eudesmol (19.08%), β-pinene (18.49%), elemol (7.12%) and (E)-caryophyllene (6.39%) as the main components. AmEO (40–90 ppm) exhibited dose- and time-dependent larvicidal activity. In vitro enzymatic assays revealed that AmEO did not affect trypsin and α-amylase activities, but stimulated AChE activity, differing from the typical AChE inhibition described in most essential oil-related studies. AmEO showed adulticidal activity starting 30 min after exposure and caused 100% mortality at all evaluated concentrations (5–25 ppm) after 24 h. Treatments with AmEO (20 and 100 ppm) significantly inhibited oviposition compared to the control after 16 h. These findings highlight the potential of AmEO as a natural insecticide, capable of affecting Ae. aegypti survival at distinct stages and inhibit oviposition. • This study reports the effects of the leaf essential oil from Algrizea minor (AmEO) against Aedes aegypti. • AmEO showed as major compound β-eudesmol, α-eudesmol, β-pinene, elemol and (E)-caryophyllene. • AmEO showed larvicidal activity and was able to stimulate acetylcholinesterase activity. • AmEO induced 100% mortality of adults at all concentrations assessed (5–25 ppm) after 24 h. • AmEO showed oviposition-deterrent activity.

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