Plantas medicinais usadas por indígenas potiguara na Paraíba: prospecção para o controle biológico do Aedes aegypti (Diptera: Culicidae)

Abstract

The Potiguara ethnic group has a diversified traditional knowledge for the treatment of diseases, being a therapeutic alternative used since remote times. In addition to being used for medicinal purposes, plants have other applications in the biological control of vectors, such as Aedes aegypti, a mosquito that requires great attention since it propagates several arboviruses, having adaptive capacity and resistance to insecticides. Biopesticides have been shown to be efficient in biological containment, in addition to causing minimal environmental impacts when compared to traditionally chemical insecticides. The aim of this study was to survey the traditional knowledge of the Potiguara indigenous people about medicinal plants used in the São Francisco and Tramataia villages. The sampling method was Snowball. Possible “in vitro” insecticidal effects of plant extracts on Aedes aegypti larvae were investigated. The extractive methods used were maceration, turbolisis and ultrasound at ethanol concentrations at 30, 50 and 70%. 75 species belonging to 40 botanical families were indicated, the most cited were Fabaceae and Lamiaceae. They are used in the treatment of 49 types of diseases, distributed in 15 categories according to the Brazilian Center for Disease Classification. The most used parts of the plants were the leaf and the bark. Alpinia zerumbet obtained the maximum value of relative importance (RI = 2.00), Stryphnodendron adstringens was the most cited species with the highest use value (VU = 0.63) and Avicennia schaueriana (RI = 1.00; VU = 0.12) was indicated for use as an antidote in cases of intoxication due to accidental ingestion of tetrodotoxin. It was also verified that the species Phyllanthus niruri showed a predisposition for the release of bioactive components in solutions with more aqueous characteristics than ethanolic ones, being the only one to present larvicidal toxic activity in all the methods used, causing necrosis of the larval tissues. The most effective lethal concentrations LC50 and LC90 (μg/ml) were obtained in treatments with 50% hydroethanolic extractions. The extract that showed the best mortality rate on Aedes aegypti was the Ultrasson with 30% ethanol extraction, offering potential for larvicide application against the vector.