| Abstract: | The aim of this study was to assess the activity of aqueous (AE) and ethanolic extracts (EE) and pilocarpine
hydrochloride, which were extracted and isolated from Pilocarpus microphyllus (Jaborandi), respectively, on Rhipicephalus (Boophilus) microplus. High performance liquid chromatography (HPLC) was performed to quantify these compounds. Larval packet and adult immersion tests were conducted with different concentrations. Five AE and EE concentrations, ranging from 6.2 to 100.0 mg mL–1, and six concentrations of pilocarpine hydrochloride, ranging from 0.7 to 24.0 mg mL–1, were tested. The lethal concentration (LC50) of each extract for larvae and engorged females was calculated through Probit analysis. The concentration of pilocarpine hydrochloride obtained from the EE and the AE was 1.3 and 0.3% (m/m), respectively. Pilocarpine hydrochloride presented the highest acaricidal activity on larvae (LC50 2.6 mg mL–1) and engorged females (LC50 11.8 mg mL–1) of R.(B.) microplus, followed by the EE which presented LC50 of 56.4 and 15.9 mg mL–1, for larvae and engorged females, respectively. Such results indicate that pilocarpine hydrochloride has acaricidal activity, and may be the primary compound responsible for this activity by P. microphyllus EE.
O objetivo desse estudo foi avaliar a atividade dos extratos aquoso (AE) e etanólico (EE) e do cloridrato de pilocarpina,
que foram, respectivamente, extraídos e isolado de Pilocarpus microphyllus (Jaborandi), sobre Rhipicephalus (Boophilus)
microplus. Cromatografia líquida de alta eficiência foi realizada para quantificação dos compostos. Testes de pacote de
larvas e de imersão de adultos foram realizados com diferentes concentrações. Cinco concentrações do AE e EE variando
de 6,2 a 100,0 mg mL–1 e seis concentrações do cloridrato de pilocarpina variando de 0,7 a 24,0 mg mL–1 foram testadas.
A concentração letal (CL50) de cada extrato para larvas e fêmeas ingurgitadas foi estimada por meio da análise Probit.
A concentração de cloridrato de pilocarpina obtida do EE e AE foi de 1,3 e 0,3% (m/m), respectivamente. O cloridrato
de pilocarpina apresentou a maior atividade carrapaticida sobre larvas (CL50 2,6 mg mL–1) e fêmeas ingurgitadas
(CL50 11,8 mg mL–1) de R. (B.) microplus, seguido do EE que apresentou CL50 de 56,4 e 15,9 mg mL–1, para larvas
e fêmeas ingurgitadas, respectivamente. Tais resultados indicam que o cloridrato de pilocarpina apresenta atividade
carrapaticida e pode ser o principal responsável pela atividade acaricida do EE de P. microphyllus.
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