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.

Acaricidal Properties of the Essential Oil FromZanthoxylum caribaeumAgainstRhipicephalus microplus

“…In a previous study, 50 and 25 l/ml dilutions of essential oils of these species were analyzed using the adult immersion test and the larval immersion test, and inhibited R. microplus egg laying (Ribeiro et al 2010). In the immersion test with R. microplus females using the essential 10.0 l/ml oil of Lippia sidoides Chamisso, mortality was Ͼ95%, while essential oil concentration of 40.0 l/ml reduced egg-laying capacity (Gomes et al 2012).…”

Glandular trichome density and essential oil composition in leaves and inflorescences of Lippia origanoides Kunth (Verbenaceae) in the Brazilian Cerrado

“…TOZIN, MARCIA O.M. MARQUES and TATIANE M. RODRIGUES Gomes et al 2012, Oliveira et al 2007, RochaGuzmán et al 2007, Veras et al 2013. Different chemotypes of L. origanoides were reported in literature and p-cimene, thymol and carvacrol are the major components most commonly found (Cavalcanti et al 2010, Oliveira et al 2007.…”

Lethal and sublethal effects of essential oil of Lippia sidoides (Verbenaceae) and monoterpenes on Chagas’ disease vector Rhodnius prolixus

“…In addition, according to the literature, the percentage of thymol varies between 2.30 and 84.9% in EOLS (Botelho et al 2007, Gomes et al 2012). On the other hand, the chemical analysis of the EOLS did not detect significant percentages of carvacrol, a thymol isomer that is usually described in the literature as the most abundant component of EOLS, along with its isomer (Botelho et al 2007).…”

“…These compounds are known to exhibit biocidal properties and have been used as extracts, pure allelochemicals, or essential oils. They are economically viable and biodegradable and, in some cases, display high activity against several vector insects (Gomes et al 2012). In addition, these compounds exhibit low toxicity against mammals, with high selectivity and low phytotoxicity (Corrêa & Salgado 2011).…”

“…The species Lippia sidoides Cham, popularly known in Brazil as ‘alecrim-pimenta’, is a typical shrub commonly found in the semi-arid northeast of Brazil. Several studies have reported the broad range of L. sidoides essential oil biological activity including antimicrobial (Botelho et al 2007), acaricidal (Gomes et al 2012), and insecticidal (Lima et al 2013) effects. Commonly, the major compounds of L. sidoides essential oil are the monotherpene thymol and its isomer carvacrol (Terblanché & Kornelius 1996).…”