The mosquitoes Aedes aegypti and Aedes albopictus are vectors of arboviruses that cause dengue, zika and chikungunya. Bioactive compounds from plants are environmentally sustainable alternatives to control these vectors and thus the arboviruses transmitted by them. The present study evaluated the larvicidal activity of an acetogenin-rich fraction (ACERF) and its main constituent annonacin obtained from Annona muricata seeds on Ae. aegypti and Ae. albopictus. The larvicidal assays were performed using different concentrations to calculate the LC50 and LC90 values observed 24 h after exposure to the treatment. Annonacin was more active against Ae. aegypti (LC50 2.65 μg·mL−1) in comparison with Ae. albopictus (LC50 8.34 μg·mL−1). In contrast, the acetogenin-rich fraction was more active against Ae. albopictus (LC50 3.41 μg·mL−1) than Ae. aegypti (LC50 12.41 μg·mL−1). ACERF and annonacin treated larvae of Ae. aegypti and Ae. albopictus showed significant differences in the inhibition of their metabolic enzymes when compared to untreated larvae. The results demonstrate the relevant larvicidal action of the acetogenin-rich fraction and annonacin showing the potential to develop new products for the control of Ae. aegypti and Ae. albopictus.

Insect resistance and environmental pollution are among the drawbacks of continuous use of synthetic insecticides against the vectors of dengue, Aedes aegypti and Aedes albopictus. The objective of this study was to analyze the composition of the essential oil of Lippia grata Schauer collected from plants, in three periods of the year, to compare the larvicidal activity and enzymatic inhibition of the dengue vectors. The oilsanalyzed by gas chromatography coupled to mass spectrometry (GC-MS), presented thymol and 1,8-cineole, as the main constituents, in all three periods. This composition was different from that found in previous studies of the species from different places, thus, suggesting a new chemotype of Lippia grata. Larvicidal tests were performed at concentrations of 100, 75, 50, 25, and 12.5 μg.mL−1 and the essential oil from the rainy season showed the best results, with LC50 of 22.79 μg.mL−1 and 35.36 μg.mL−1 against Ae. aegypti and Ae. albopictus, respectively; this result was better than other reports. In the rainy period, however, there was a greater variety of components, which led to a better larvicidal effect, possibly due to synergistic action with minor constituents. Total proteins, amylases, and acetylcholinesterase of both species were inhibited by the oils.

RESUMO As propriedades terapêuticas de fungos endofíticos conduzem à pesquisa dos princípios ativos de várias espécies. O objetivo deste trabalho foi obter extratos orgânicos de fungos endofícos obtidos da planta J. curcas bem como de outros fungos da coleção da EMBRAPA Agroindustria Tropical e avaliar sua bioatividade como anticâncer, antioxidante e anticolinesterasica. Para tanto, as sementes de J. curcas foram incubadas por três dias a 25°C em placas de Petri descartáveis contendo agardextrose-batata, das quais foram isoladas cepas de Aspergillus nidulans. Da micoteca da EMBRAPA selecionados foram duas cepas do gênero Dichotomophthora. A atividade citotóxica foi avaliada em céluas de tumores HCT-116, PC-3 e SF-295 mas somente o extrato de uma Dichotomophthora sp. apresentou atividade contra HCT-116 e PC-3. Quanto a atividade antioxidante os três fungos apresentaram metabólitos antioxidantes contra o radical DPPH, sendo as cepas de A. nidulans com extratos mais promissores. Os extratos das duas cepas de Dichotomophthora foram os mais promissores na de inibição da enzima AChE. Portanto os fungos estudados apresentam propriedades biológias que indicam o seu potencial para estudos mais aprofundados de isolamento e caracterização de seus compostos bioativos.