Ação inseticida in vitro do óleo essencial de Lippia gracilisSchauer sobre Damalinia Bovicola ovis (Schrank, 1781) / In vitro action of Lippia gracilis Schauer essential oil on Damalinia Bovicola ovis (Schrank, 1781)

O objetivo deste trabalho é avaliar a eficácia inseticida in vitro do óleo essencial de Lippia gracilis sobre Bovicolaovis. Os espécimes (n = 900) de B.ovis foram coletados de ovinos naturalmente infestados, distribuídos aleatoriamente em grupos, e submetidos aos diferentes tratamentos: (G1) 1.000 a 15,6 mg/ml óleo essencial de Lippia gracilis; (G2) Tween 80 a 3% (controle negativo), e: (G3) Amitraz 1,25 g/mL (controle positivo). Realizou-se 4 réplicas (25 piolhos por réplica) para cada tratamento. A viabilidade dos piolhos foi avaliada nos tempos de 1, 3, 6, 24, 48 e 72 h. Os dados foram expressos em eficácia média ± desvio padrão (SPSS versão 23.0) e diferenças estatísticas dos grupos experimentais foram obtidas por Kruskal-Wallis e Friedman. Para obtenção da CI50e CI90 foi realizada Regressão de Probit, com nível de significância de p< 0,05. O óleo essencial de L. gracilis nas concentrações de 100 a 62,5 mg/mL apresentaram eficácia de 100%, 1 h pós-exposição. Os valores de CI50 e CI90 foram 18,1 mg/mL e 44,9 mg/mL, respectivamente. Dessa forma, concluímos que o óleo essencial de L. gracilis apresentou eficácia sobre B.ovis in vitro.

The objective of this work is to evaluate the in vitro insecticidal efficacy of the essential oil of Lippia gracilis against Bovicolaovis. The specimens (n = 900) of B.ovis were collected from naturally infested sheep, randomly distributed in groups, and subjected to different treatments: (G1) 1,000 to 15.6 mg/ml essential oil of Lippia gracilis; (G2) 3% Tween 80 (negative control), and: (G3) Amitraz 1.25 g/mL (positive control). 4 replicates (25 lice per replica) were performed for each treatment. Louse viability was assessed at 1, 3, 6, 24, 48 and 72 h. The data were expressed as mean efficacy ± standard deviation (SPSS version 23.0) and statistical differences in the experimental groups were obtained by Kruskal-Wallis and Friedman. Probit regression was performed to obtain the IC50 and CI90, with a significance level of p <0.05. The essential oil of L. gracilis at concentrations of 100 to 62.5 mg/mL showed 100% efficacy, 1 h post-exposure. The IC50 and CI90 values were 18.1 mg/mL and 44.9 mg/mL, respectively. Thus, we conclude that L. gracilis essential oil is effective on B. ovis.

Ação inseticida in vitro do óleo essencial de Lippia gracilis Schauer sobre Damalinia Bovicola ovis (Schrank, 1781) / In vitro action of Lippia gracilis Schauer essential oil on Damalinia Bovicola ovis (Schrank, 1781)

O objetivo deste trabalho é avaliar a eficácia inseticida in vitro do óleo essencial de Lippia gracilis sobre Bovicolaovis. Os espécimes (n = 900) de B.ovis foram coletados de ovinos naturalmente infestados, distribuídos aleatoriamente em grupos, e submetidos aos diferentes tratamentos: (G1) 1.000 a 15,6 mg/ml óleo essencial de Lippia gracilis; (G2) Tween 80 a 3% (controle negativo), e: (G3) Amitraz 1,25 g/mL (controle positivo). Realizou-se 4 réplicas (25 piolhos por réplica) para cada tratamento. A viabilidade dos piolhos foi avaliada nos tempos de 1, 3, 6, 24, 48 e 72 h. Os dados foram expressos em eficácia média ± desvio padrão (SPSS versão 23.0) e diferenças estatísticas dos grupos experimentais foram obtidas por Kruskal-Wallis e Friedman. Para obtenção da CI50e CI90 foi realizada Regressão de Probit, com nível de significância de p< 0,05. O óleo essencial de L. gracilis nas concentrações de 100 a 62,5 mg/mL apresentaram eficácia de 100%, 1 h pós-exposição. Os valores de CI50 e CI90 foram 18,1 mg/mL e 44,9 mg/mL, respectivamente. Dessa forma, concluímos que o óleo essencial de L. gracilis apresentou eficácia sobre B.ovis in vitro.

The objective of this work is to evaluate the in vitro insecticidal efficacy of the essential oil of Lippia gracilis against Bovicolaovis. The specimens (n = 900) of B.ovis were collected from naturally infested sheep, randomly distributed in groups, and subjected to different treatments: (G1) 1,000 to 15.6 mg/ml essential oil of Lippia gracilis; (G2) 3% Tween 80 (negative control), and: (G3) Amitraz 1.25 g/mL (positive control). 4 replicates (25 lice per replica) were performed for each treatment. Louse viability was assessed at 1, 3, 6, 24, 48 and 72 h. The data were expressed as mean efficacy ± standard deviation (SPSS version 23.0) and statistical differences in the experimental groups were obtained by Kruskal-Wallis and Friedman. Probit regression was performed to obtain the IC50 and CI90, with a significance level of p <0.05. The essential oil of L. gracilis at concentrations of 100 to 62.5 mg/mL showed 100% efficacy, 1 h post-exposure. The IC50 and CI90 values were 18.1 mg/mL and 44.9 mg/mL, respectively. Thus, we conclude that L. gracilis essential oil is effective on B. ovis.

Chemical composition and antigenotoxic properties of Lippia alba essential oils

The present work evaluated the chemical composition and the DNA protective effect of the essential oils (EOs) from Lippia alba against bleomycin-induced genotoxicity. EO constituents were determined by Gas Chromatography/Mass Spectrometric (GC-MS) analysis. The major compounds encountered being citral (33 percent geranial and 25 percent neral), geraniol (7 percent) and trans-β-caryophyllene (7 percent) for L. alba specimen COL512077, and carvone (38 percent), limonene (33 percent) and bicyclosesquiphellandrene (8 percent) for the other, COL512078. The genotoxicity and antigenotoxicity of EO and the compounds citral, carvone and limonene, were assayed using the SOS Chromotest in Escherichia coli. The EOs were not genotoxic in the SOS chromotest, but one of the major compound (limonene) showed genotoxicity at doses between 97 and 1549 mM. Both EOs protected bacterial cells against bleomycin-induced genotoxicity. Antigenotoxicity in the two L. alba chemotypes was related to the major compounds, citral and carvone, respectively. The results were discussed in relation to the chemopreventive potential of L. alba EOs and its major compounds.