Estudo químico e biológico de Piper capitarianum (Piperaceae) para o controle de Aedes aegypti e Aedes albopictus (Culicidae)

Abstract

The Aedes aegypti and Aedes albopictus mosquitoes are important vectors in the transmission of dengue, chikungunya and Zika in Brazil and other countries. Due to increasing resistance to chemical insecticides among vector populations, environmentally sound vector management strategies are receiving increasing attention. Thus, the present study aimed to evaluate the chemical composition of essential oils and extracts of Piper capitarianum, as well as their insecticidal potential, for the control of A. aegypti and A. albopictus. The plant species was collected at EMBRAPA where they were removed from leaves, branches and inflorescences for oil extraction and preparation of extracts. Essential oils were analyzed by GC-MS and the extracts were analyzed by TLC and NMR. The nanoemulsions were prepared by the phase inversion method, containing distilled water (aqueous phase), essential oil, and the surfactants (oil phase) mixed under ultrasonic agitation at 100 rpm for 10 min. Eggs of A. aegypti and A. albopictus were obtained from the Laboratory of Malaria and Dengue at INPA, maintained until reaching the third larval instar, when they were used in bioassays. The data obtained were analyzed using the POLO PC® program to calculate the respective CL50 and CL90. In essential oils, trans-caryophyllene, humulene and linalool were identified as the main substances. The most active extract was subjected to bioassay- guided fractionation which resulted in the isolation of flavone and chalcone with biological activity. The results of this study showed the larvicidal and adulticidal activity of oils, nanoemulsions and extracts of P. capitarianum, indicating morphological changes in the intestine and siphon observed by optical and electronic microscopy. Therefore, oils and extracts obtained from P. capitarianum can be considered as a promising source for the development of new insecticides for the control of vector insects.