Avaliação da atividade larvicida de extratos e óleo essencial de Piper capitarianum Yunck , 1966 (Piperaceae) sobre Aedes aegypti Linnaeus, 1762 e Anopheles sp (Culicidae) em laboratório

Abstract

Mosquitoes are responsible for serious problems of global public health. The Aedes aegypti and Anopheles are important vectors in the transmission of dengue and malaria in Brazil. As there is no vaccine available, the main way to reduce dengue indices and malaria is controlling the proliferation of the insect vector that is based on vector control through the application of chemical insecticides that allow contamination of the environment and resistance selection in populations of mosquitoes as a result of intense application. The use of plant extracts has been gaining attention as an alternative in vector control, especially in the Amazon environment, since the plant employees have chemical compounds with larvicidal activity and insecticide. This study aimed to carry out phytochemical prospecting and evaluation of larvicidal activity of essential extracts and oil P. capitarianum for controlling A. aegypti and Anopheles sp. under laboratory conditions. A. aegypti eggs were collected in two neighborhoods of Manaus, and the larvae of Anopheles were obtained in the breeding of Puraquequera neighborhood. Bioassays were prepared with the extracts, oil and distilled water at the following concentrations: 500, 250, 100, 50, 25 mg / ml, positive control (temephos) and negative control (DMSO, H2O and Tween), tested at Rockefeller A. aegypti and Anopheles which were evaluated by observing the mortality of larvae at 24, 48 and 72 hours of exposure. The hexane extracts, methanolic and aqueous were prepared by Soxhlet system, infusion method and the essential oil was extracted by hydrodistillation and analyzed by GC-MS. The extracts were submitted to phytochemical screening, which was analyzed by thin layer chromatography (TLC), using specific developers. The phytochemical study of the extracts revealed the presence of chemical classes anthraquinones, flavonoids, terpenes, alkaloids and steroids. In the essential oil were identified as major constituents, the β-caryophyllene (34.08%), β-myrcene (13.77%) and α-humulene (13.32%), respectively. Hexane and methanolic extracts of the flowers and essential oil of P. capitarianum showed larvicidal activity in the two higher concentrations (500 and 250 mg / mL), with 100% mortality of A. aegypti and Anopheles sp, After 72 hours exposure, It is proving to be a viable alternative for the control of vectors.