Atividade repelente e carrapaticida de compostos derivados do óleo de coco contra Amblyomma sculptum

• Autor(a) principal: Santos, Mayara Macêdo Barrozo
• Data de Publicação: 2021
• Tipo de documento: Dissertação
• Idioma: por
• Título da fonte: Repositório Institucional da UFG
• Texto Completo: http://repositorio.bc.ufg.br/tede/handle/tede/11329
• topic: Ácidos graxos; Bioensaios in vitro; Carrapato-estrela; Fitoterapia; Repelência; Fatty acids; In vitro bioassays; Star tick; Herbal medicine; Repellency; CIENCIAS AGRARIAS::MEDICINA VETERINARIA::MEDICINA VETERINARIA PREVENTIVA::SAUDE ANIMAL (PROGRAMAS SANITARIOS)

Amblyomma sculptum can parasitize several mammals, including humans, and is the main vector of the Rickettsia rickettsii bacterium in Brazil, the etiological agent of Brazilian spotted fever. Several studies have been carried out with products of plant origin to control ticks. In addition, the use of repellents is an important tool to prevent infestations. The present study aimed to evaluate the repellency of unfed nymphs of A. sculptum against substances derived from coconut oil (C12 dodecanoic acid methyl ester; C10 decanoic acid methyl ester; and coconut free fatty acid in lavender oil formulation) and catnip oil (Nepeta cataria); through modified Petri dish bioassays and, to evaluate the tick activity of these substances by means of the larval packet test. For the Petri dish test, a semicircle of filter paper containing the substance to be tested at a concentration of 10% diluted in ethanol and another semicircle containing the solvent (ethanol), were placed inside the dish; six non-fed nymphs were placed in the center of each plate and their location was assessed at 1, 3, 5, 10, 15 and 30 minutes and at 24, 48, 72, 96 and 168 hours after the start of the test. For the larval packet test, the substances were used in five concentrations (2.5; 5; 10; 15 and 20 mg / mL) on non-fed larvae of A. sculptum to assess mortality after 24 hours of treatment. As a result, all substances showed repellency, with the fatty acid free of coconut oil conferring repellency for 7 days, while N. cataria oil and C10 methyl ester showed repellency for 4 and 3 days, respectively. The concentration of the C12 methyl ester, effective against more than 93% of the tested larvae, was 15 mg / mL and the concentration, of that same substance, of 20mg / mL conferred 100% mortality. Thus, our results indicate that compounds derived from coconut oil have a repellent and tick effect on immature stages of A. sculptum and can be formulated to protect humans and other animals from infestation, as well as against pathogens transmitted by this species of tick.