title: Chemical composition and acaricidal activity of essential oil from Lippia sidoides on larvae of Dermacentor nitens (Acari: Ixodidae) and larvae and engorged females of Rhipicephalus microplus (Acari: Ixodidae).
abstract: The aim of this work was to identify the compounds and to investigate the acaricidal activity of the essential oil from the leaves of Lippia sidoides on Rhipicephalus microplus and Dermacentor nitens. The oil was obtained by hydrodistillation and analyzed by gas chromatography (GC/FID) and gas chromatography/mass spectrometry. In total, 15 compounds comprising 99.97 % of the total peak area were identified. The main constituent of the essential oil was thymol (67.60 %). The acaricidal activity was assessed by the modified larval packet test, with oil concentrations of 2.5, 5.0, 10.0, 15.0, and 20.0 μl/ml, and by the female immersion test with concentrations of 10.0, 20.0, 40.0, 60.0, and 80.0 μl/ml. The mortality of the R. microplus and D. nitens larvae was greater than 95 % starting at concentrations of 10.0 and 20.0 μl/ml, respectively. In the test with the engorged females, the L. sidoides essential oil starting at a concentration of 40.0 μl/ml caused a significant reduction (p < 0.05) in the values of the egg mass weight and egg production index. The viability of the eggs was affected in all the treated groups, with significantly lower hatching rates (p < 0.05) in relation to the control group. The control percentages at concentrations of 10.0, 20.0, and 30.0 μl/ml were 54, 57, and 72 %, and reached 100 % at the highest two concentrations (60.0 and 80.0 μl/ml). Therefore, it can be concluded that the essential oil from the leaves of L. sidoides has acaricidal activity on R. microplus and D. nitens.
authors.affiliation: Departamento de Química, Instituto de Ciências Exatas, Universidade Federal Rural do Rio de Janeiro, 23890-000 Seropédica, RJ, Brazil.
authors.forename: Geovany Amorim
authors.initials: GA
authors.lastname: Gomes
authors.forename: Caio Márcio de Oliveira
authors.initials: CM
authors.lastname: Monteiro
authors.forename: Tatiane de Oliveira Souza
authors.initials: Tde O
authors.lastname: Senra
authors.forename: Viviane
authors.initials: V
authors.lastname: Zeringota
authors.forename: Fernanda
authors.initials: F
authors.lastname: Calmon
authors.forename: Renata da Silva
authors.initials: Rda S
authors.lastname: Matos
authors.forename: Erik
authors.initials: E
authors.lastname: Daemon
authors.forename: Roberto Wagner da Silva
authors.initials: RW
authors.lastname: Gois
authors.forename: Gilvandete Maria Pinheiro
authors.initials: GM
authors.lastname: Santiago
authors.forename: Mario Geraldo
authors.initials: MG
authors.lastname: de Carvalho
mesh_terms: D056810:Acaricides / Q000737:chemistry* / Q000302:isolation & purification / Q000494:pharmacology*; D000818:Animals; D001681:Biological Assay; D003870:Dermacentor / Q000187:drug effects*; D005260:Female; D008401:Gas Chromatography-Mass Spectrometry; D007814:Larva / Q000187:drug effects; D032411:Lippia / Q000737:chemistry*; D009822:Oils, Volatile / Q000737:chemistry* / Q000302:isolation & purification / Q000494:pharmacology*; D018515:Plant Leaves / Q000737:chemistry; D048494:Rhipicephalus / Q000187:drug effects*; D016019:Survival Analysis; D015053:Zygote / Q000187:drug effects
chemical_list: D056810:Acaricides; D009822:Oils, Volatile