title: Activity of essential oil of Lippia triplinervis Gardner (Verbenaceae) on Rhipicephalus microplus (Acari: Ixodidae).
abstract: The objective of this work was to characterize and investigate the acaricidal activity of the essential oil of the aerial parts of Lippia triplinervis at different concentrations on unengorged larvae and engorged females of Rhipicephalus microplus. The essential oil yielded 2.21 % (w/w to dry matter) and was composed mainly of carvacrol (31.9 %), thymol (30.6 %), and p-cymene (12.3 %). Two tests were performed to assess the acaricidal activity: the modified larval packet test, with concentrations of 2.5, 5.0, 10.0, 15.0, and 20.0 mg/mL and the female immersion test, with concentrations of 10.0, 20.0, 30.0, 40.0, and 50.0 mg/mL. There were ten repetitions for each concentration, and for each test, a control group was formed in which the ticks were treated with Tween 80 (20 mg/mL). The experimental groups were kept in a climate-controlled chamber (27 ± 1 °C and RH >80 %). The mortality of the larvae was above 95 % in all the groups tested and reached 100 % as of the 5.0 mg/mL concentration, while the control group exhibited 0 % mortality. In the female immersion test, there was a significant decline (p < 0.05) in the egg mass weight, egg production index, and hatching percentage starting at the concentration of 30.0, 40.0, and 20.0 mg/mL, respectively, and the control percentage at the concentrations of 40.0 and 50.0 mg/mL were above 90 and 95 %. The L. triplinervis oil as thus an alternative source of the monoterpenes thymol, carvacrol, and p-cymene, and its toxicity on R. microplus larvae and females makes it promising possibility for control of this tick.
authors.affiliation: Grupo de Química Supramolecular e Biomimética, Departamento de Química, Universidade Federal de Viçosa, Campus Universitário, Avenida PH Rolfs, s/n, Viçosa, Minas Gerais, Brazil 36570-000.
authors.forename: Tiago Coelho de Assis
authors.initials: TC
authors.lastname: Lage
authors.forename: Ricardo Marques
authors.initials: RM
authors.lastname: Montanari
authors.forename: Sergio Antonio
authors.initials: SA
authors.lastname: Fernandes
authors.forename: Caio Márcio
authors.initials: CM
authors.lastname: de Oliveira Monteiro
authors.forename: Tatiane
authors.initials: T
authors.lastname: de Oliveira Souza Senra
authors.forename: Viviane
authors.initials: V
authors.lastname: Zeringota
authors.forename: Fernanda
authors.initials: F
authors.lastname: Calmon
authors.forename: Renata
authors.initials: R
authors.lastname: da Silva Matos
authors.forename: Erik
authors.initials: E
authors.lastname: Daemon
mesh_terms: D056810:Acaricides / Q000737:chemistry / Q000302:isolation & purification / Q000494:pharmacology*; D000818:Animals; D000081007:Cymenes; D005260:Female; D007814:Larva / Q000187:drug effects; D032411:Lippia / Q000737:chemistry*; D039821:Monoterpenes / Q000302:isolation & purification / Q000494:pharmacology; D009822:Oils, Volatile / Q000737:chemistry / Q000302:isolation & purification / Q000494:pharmacology*; D048494:Rhipicephalus / Q000187:drug effects*; D016019:Survival Analysis; D013943:Thymol / Q000302:isolation & purification / Q000494:pharmacology
chemical_list: D056810:Acaricides; D000081007:Cymenes; D039821:Monoterpenes; D009822:Oils, Volatile; C007210:4-cymene; D013943:Thymol; C073316:carvacrol