Avaliação do efeito tóxico e genotóxico do óleo essencial de Piper marginatum (Jacq.) ao controle de Aedes aegypti, na Amazônia central

Abstract

Aedes aegypti, an important vector of arboviruses responsible for dengue, Zika, and chikungunya, has shown resistance to synthetic chemical insecticides, which has driven the search for effective vector control alternatives that are less harmful to the environment and to non-target organisms. Among the promising options, the use of essential oils (EOs) from plants of the Piperaceae family, especially from the Piper genus, stands out. In this context, the present study investigated the toxic and genotoxic effects of the essential oil of Piper marginatum (EOPM) on Ae. aegypti larvae and isogenic BALB/c strain mice (Mus musculus), aiming to evaluate its potential as an alternative for vector control. The EOPM was extracted by hydrodistillation, and its composition was determined by Gas Chromatography coupled to Mass Spectrometry (GC-MS), identifying 49 compounds, mainly sesquiterpenes and monoterpenes. The larvicidal bioassay on Ae. aegypti demonstrated larval mortality at all tested concentrations (50 to 90 µg/mL), with a progressive increase in mortality with rising concentration and exposure time. The Lethal Concentrations (LC10, LC50, and LC90) determined after 72 hours were 44.49, 66.61, and 88.73 µg/mL, respectively. In the genotoxicity bioassay, conducted with larvae exposed to concentrations of 15, 25, and 35 µg/mL, neuroblastic cells were analyzed, and genotoxic damage was observed, including micronuclei, in generations 1 and 2 (G1 and G2), with significant differences (p < 0.001) compared to the controls, especially the negative control (NC), although differences were also noted relative to the positive control (PC). In BALB/c mice, the acute oral toxicity test revealed no adverse effects at doses up to 2000 mg/kg/day, classifying EOPM as safe (Category C, according to OECD). In the micronucleus test, EOPM did not cause a significant increase in micronuclei in bone marrow, whereas the mutagenic agent methyl methanesulfonate (MMS), used as the PC, showed strong mutagenic activity. Cytotoxicity was dose-dependent after 24 hours, with a reduction in the frequency of polychromatic erythrocytes (PCEs) and in the polychromatic to normochromatic erythrocyte (PCE:NCE) ratio, an effect that was not maintained after 48 hours. These results indicate that EOPM exhibits larvicidal and genotoxic activity against Ae. aegypti without evidence of acute oral toxicity or mutagenicity in mammals under the tested conditions. Thus, EOPM may represent an effective and viable alternative for Ae. aegypti population control and, potentially, a safer approach from an environmental perspective for the development of bioinsecticides targeting epidemiologically relevant vectors. Further studies are needed to confirm its safety in other non-target organisms.