Estudo do potencial larvicida do extrato aquoso das sementes de Bauhinia cheilantha (Bong.) Steud contra vetores de arboviroses

Abstract

The increasing incidence of arboviruses, diseases caused by viruses transmitted by arthropods such as dengue, Zika, and Chikungunya, spread by vector mosquitoes including Aedes aegypti and Aedes albopictus, has intensified the search for new vector control strategies. Given the limitations of chemical insecticides, such as environmental impact, effects on non-target organisms, and the emergence of resistant vectors, botanical extracts stand out as promising sources of bioinsecticidal molecules with greater biodegradability, lower cost, and environmental safety. In this context, the present study investigated the larvicidal potential of the aqueous extract from the seeds of Bauhinia cheilantha, a legume popularly known as mororó, found in the Brazilian Northeast, as a candidate bioinsecticide for the control of A. aegypti and A. albopictus larvae. The seeds were ground into a fine powder (sieved through a 40-mesh screen), homogenized in distilled water (1:10), and subjected to aqueous extraction (80 °C) for 3 hours. The resulting extract, named EAM, was lyophilized and subsequently analyzed for larvicidal activity, total soluble protein content, and dry weight. Fourth-instar larvae of A. aegypti and A. albopictus were exposed to different extract concentrations in quintuplicate bioassays, with mortality assessed after 24 and 48 hours. Lethal concentrations (CL50 and CL90) were calculated using Probit analysis, and morphological analyses were conducted to identify structural changes in the larvae. The results demonstrated that the extract exhibits larvicidal activity, with low lethal concentrations ranging from 0.14 to 0.91 mg/mL, and induced abdominal shortening in the larvae. These findings reinforce the potential of B. cheilantha seed aqueous extract (EAM) for the development of sustainable bioinsecticides for vector control, with the possibility of large-scale production. Further studies are welcome to complement this research and expand knowledge on its composition, mechanisms of action, and application in different mosquito life cycle stages.