Siparuna gesnerioides and Siparuna guianensis Essential Oils in Aedes aegypti Control: Phytoanalysis, Molecular Insights for Larvicidal Activity and Selectivity to Non-Target Organisms

Synthetic insecticides are widely used against mosquitoes, but misuse has led to environmental and health concerns. Plant-derived alternatives, such as essential oils, seem to offer a safer option, minimizing these problems without compromising efficacy. In this study, we evaluated the essential oil from <i>Siparuna gesnerioides</i> (Kunth) A.DC., a Neotropical plant, for its effectiveness in controlling <i>Aedes</i> (<i>Stegomyia</i>) <i>aegypti</i> (Linnaeus) larvae, a major vector of human diseases. We first assessed the phytochemistry of the essential oil and used in silico approaches to predict potential physiological targets of its larvicidal activities. Selectivity assays were conducted with <i>Belostoma anurum</i> (Herrich-Schäffer), a non-target predatory water bug. The major constituents of <i>S. gesnerioides</i> essential oil were γ-elemene (45.8%) and germacrene D (43.8%). This essential oil effectively killed larvae from both susceptible and resistant mosquito strains (LC₅₀ = 0.070 μg/mL). However, such concentrations killed more than 80% of <i>B. anurum</i> nymphs. Molecular modeling suggested that the essential oil major components (γ-elemene and germacrene D) interact stably with mosquito acetylcholinesterases (AChEs), indicating a potential mechanism of action. Our results reinforce the potential of <i>Siparuna</i> essential oils in mosquito control. Nevertheless, the non-selective impact on mosquito predators, as seen with <i>S. gesnerioides</i>, highlights the need for caution in field applications.