Repellent activity of Piper macedoi Yunck volatile oil against Aedes aegypti
Phytochemistry, mosquitoes, essential oil, insecticide
Abstract: In Brazil, the increase in arboviral epidemics has been perpetuated as a serious public health problem. Diseases such as dengue, the reemergence of Yellow Fever, Chikungunya and Zika are associated with high rates of infestation by the Aedes aegypti mosquito. As a way of adding to the prevention of these diseases along with current vector control measures, encouraging the use of repellents by the population, especially based on natural products, can be of great value. The genus Piper with species native to the Atlantic Forest, such as Piper macedoi and Piper aduncum, showed promising results regarding insecticidal activity. Thus, the objective of the present study was to evaluate the repellent activity of the volatile oil of P. macedoi against Aedes aegypti mosquitoes and to carry out a systematic review on Piperaceae species tested as insecticides and repellents against A. aegypti. Essential oils were obtained from fresh leaves using the hydrodistillation method in a Clevenger-type apparatus, at the Interdisciplinary Laboratory II, UFSB -CPF. Virus-free Aedes aegypti eggs were donated by the Federal Institute's breeding center in Norte de Minas. The repellency test was approved by the Research Ethics Committee. The essential oil was tested in 04 healthy volunteers, submitted to anamnesis and with absence of dermatological diseases and other significant comorbidities. The evaluation was carried out after applying the formulations with the essential oil dilutions in the hand and forearm of the volunteers exposed to mosquitoes, created in a cage under control for the bioassays. Different concentrations of oils diluted in base cream was tested: 0.25%; 1.25%; 2.50%; 3.75%, 5.0%; an industrial repellent positive control with DEET; and as a negative control, on the other hand/forearm, the application of nonionized base cream. The evaluation was carried out by counting the number of mosquito landings for 03 minutes without a break. The oil presented a very interesting result. In the systematic review, 16 articles were selected for data analysis, with 3 articles studying more than one species of Piperaceae, totaling 19 studies of the family. All species studied were from the genus Piper: P. aduncum, P. betle, P. capitarianum, P. corcovadensi, P. longum, P. nigrum, P. retrofractum and Piper sarmentosum. New studies evaluated the repellent activity of volatile oils against Aedes in human volunteers and evaluated the insecticidal/adulticidal activity. Piper aduncum was the most prevalent species.