Atividade biológica de extratos acetato de etila, etanólico e aquoso de timbó (Lonchocarpus floribundus) sobre carrapato bovino / Biological activity of ethylic acetate, ethanolic and aqueous extracts of timbo (Lonchocarpus floribundus) on cattle tick

Ethylic acetate, ethanolic and aqueous roots extracts of Lonchocarpus floribundus were used to evaluate their biological activity on cattle tick Rhipicephalus (Boophilus) microplus. Adult ticks were collected in artificially infested cattle, separated into groups of ten individuals, weighed and immersed separately in the extracts of L. Floribundus roots at concentrations of 5, 25, 50, 75 and 100 mg mL-1. For biological evaluation 14-21-day-old larvae were used, which were immersed in the extracts at concentrations of 1, 5, 10, 15 and 20 mg mL-1. After treatment, each group was placed in a Petri dish and maintained at 27 ± 1 ºC and 80 ± 5% relative humidity. The extracts evaluated were not effective to induce mortality of over 50%-engorged female. The ethylic acetate and ethanolic extracts induced 100% mortality of larvae. The ethanolic extract was more toxic (median lethal concentration, LC50, of 2.1 mg mL-1) than the ethylic acetate extract (LC50 = 4.1 mg mL-1). For the ethanolic extract it was estimated a median inhibitory concentration (IC50) of 3.0 mg mL-1 and it was more toxic than the other extracts on this parameter. Among the three extracts evaluated, the ethylic acetate and ethanolic extracts showed the highest potential for the control of reproduction of R. (B.) microplus, reaching 100% at concentration of 5 mg mL-1. The L. Floribundus root extracts showed biological activity on cattle tick.

Os extratos acetato de etila, etanólico e aquoso de raízes de Lonchocarpus floribundus foram utilizados, a fim de avaliar a atividade biológica sobre carrapato bovino. Carrapatos adultos foram coletados em bovinos infestados artificialmente, separados em grupos de dez indivíduos, pesados e imersos, separadamente, nos extratos de raízes de L. Floribundus, nas concentrações de 5, 25, 50, 75 e 100 mg mL-1. Para a avaliação em larvas, foram utilizados indivíduos de 14 a 21 dias, os quais foram imersos nos extratos nas concentrações de 1, 5, 10, 15 e 20 mg mL-1. Após o tratamento, cada grupo foi colocado em placa de Petri e incubado a 27 ± 1 ºC e umidade relativa de 80 ± 5%. Os extratos avaliados não foram eficazes para induzir, acima de 50%, a mortalidade de fêmeas ingurgitadas. Os extratos acetato de etila e etanólico induziram 100% de mortalidade de larvas. Entretanto, quanto aos valores de concentração letal mediana (CL50), o extrato etanólico (CL50 = 2,1 mg mL-1) foi mais tóxico que o extrato acetato de etila (CL50 = 4,1 mg mL-1). O extrato etanólico estimou concentração inibitória mediana (CI50) de 3,0 mg mL-1 e foi mais tóxico que os demais extratos quanto a este parâmetro de avaliação. Entre os três extratos avaliados, os extratos acetato de etila e etanólico apresentaram os melhores resultados quanto ao controle de reprodução de R. (B.) microplus, atingindo 100% na concentração de 5 mg mL-1. Os extratos de raízes de L. Floribundus apresentaram atividade biológica sobre carrapato bovino.

Acaricidal activity of Palicourea marcgravii, a species from the Amazon forest, on cattle tick Rhipicephalus (Boophilus) microplus.

Leaves of Palicourea marcgravii were extracted successively with hexane, ethyl acetate and ethanol in order to evaluate their acaricidal activity on larvae and adult stages of the cattle tick Rhipicephalus (Boophilus) microplus. The ethyl acetate extract showed the highest bioactivity of the tested extracts, which contained 0.12% monofluoroacetic acid. On engorged female, the ethyl acetate extract showed a lethal concentration 50% - LC(50)=30.08 mg ml(-1), inhibitory concentration 50% - IC(50)=5.79 mg ml(-1) and lethal time 50% - LT(50)=4.72 days; 100% reproduction was controlled at concentrations of 50 mg ml(-1) and on larvae the ethyl acetate extract showed a LC(50)=2.46 mg ml(-1). No alkaloids were detected in any of the extracts. This is the first report on the acaricidal activity of P. marcgravii extracts against R. microplus as well as the acaricidal properties of a plant species containing monofluoroacetic acid.

Toxicity of Piper aduncum L. (Piperales: Piperaceae) from the Amazon forest for the cattle tick Rhipicephalus (Boophilus) microplus (Acari: Ixodidae).

The mortality of 14-21-day-old Rhipicephalus (Boophilus) microplus larvae, and the mortality and fertility of groups of engorged adult females exposed to different concentrations of hexane, ethyl acetate and ethanol extracts of spiked pepper (Piper aduncum) were evaluated, using a completely randomized design with five treatment groups, two control groups, and two replicates for the larvae and five replicates for the adult females. Similar methodology was used to investigate the toxicity of the essential oil hydro-distillate (94.84% dillapiole) obtained from the P. aduncum crude hexane extract. The LC(50) of the hexane extract was 9.30 mg ml(-1) for larvae and the reproduction reduction ranged from 12.48% to 54.22%, while 0.1mg/ml(-1) of the essential oil induced 100% mortality in larvae. Literature reports on natural products active against R. microplus were listed and compared with the results presented here. These results indicate that P. aduncum extracts, and particularly its essential oil, are potential alternative control agents for R. microplus.