O jambu (Acmella oleracea) e sua ação acaricida: estudo dos efeitos sobre a morfofisiologia dos sistemas reprodutores masculino e feminino de Amblyomma cajennense (Fabricius, 1787) (Acari: Ixodidae) a ele expostos
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Data
2019-05-27
Autores
Anholeto, Luís Adriano [UNESP]
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Universidade Estadual Paulista (Unesp)
Resumo
Os resultados obtidos no presente estudo tanto para as fêmeas, quanto para os machos de carrapatos Amblyomma cajennense confirmaram que o extrato etanólico bruto obtido a partir das flores, folhas e caule de Acmella oleracea tem potencial acaricida, informação esta que poderá futuramente ser utilizada na estratégia de controle desses ectoparasitas. Ficou aqui estabelecido a concentração letal de 50% (CL50) de 17,6335 mg/mL para as fêmeas semi-ingurgitadas, enquanto para os machos alimentados da mesma espécie esta foi de 29,4534 mg/mL. Quando expostos às concentrações de 6,2; 12,5 e 25 mg/mL do extrato etanólico de A. oleracea, os machos apresentaram danos morfológicos e ultraestruturais no seu sistema reprodutor, sobretudo nas células secretoras do complexo de glândulas acessórias. Para as fêmeas, quando estas foram expostas às concentrações de 3,1; 6,2 e 12,5 mg/mL, também foram observadas alterações no sistema reprodutor, que ocorreram principalmente nos ovócitos em estágios iniciais de desenvolvimento (I e II). Além disso, foram obtidos dados sobre a ação do análogo alcino do espilantol, que demonstraram que o mesmo foi capaz de reduzir a viabilidade e alterar a morfologia de duas linhagens celulares obtidas de embriões de Rhipicephalus microplus: BME/CTVM6, derivadas de carrapatos resistentes a organofosforados, organoclorados e amitraz, e BME/CTVM2, derivadas de carrapatos susceptíveis a acaricidas. Quando se estudou a ação da mesma molécula nas células BME/CTVM6 infectadas com Ehrlichia minasensis, verificou-se que houve redução de quase dois terços na porcentagem de células infectadas após a exposição ao produto. Os dados obtidos no presente estudo, sinalizaram que o uso do análogo alcino do espilantol também poderá ser uma estratégia promissora para uso no controle de carrapatos, bem como do controle de patógenos por eles transmitidos.
The results obtained in the present study confirmed that the crude ethanolic extract obtained from the flowers, leaves and stem of Acmella oleracea has acaricidal potential against males and females of Amblyomma cajennense ticks. The lethal concentration of 50% (LC50) was stablished: 17.6335 mg/mL for semi-engorged females and 29.4534 mg/mL for males. The males of A. cajennense ticks when exposed to concentrations of 6.2; 12.5 and 25 mg/mL of the A. oleracea ethanolic extract presented severe morphological and ultrastructural damages in reproductive system, especially in the secretory cells of the accessory gland complex. In the case of females, when they were exposed to concentrations of 3.1; 6.2 and 12.5 mg/mL alterations in their reproductive system was observed. The alterations were mainly in oocytes in the early stages of development (I and II). The data obtained with the use of the alkyne analogue of spilanthol showed that it was able to reduce the viability and change the morphology of two tick cell lines obtained from Rhipicephalus microplus: BME/CTVM6 derived from ticks resistant to organophosphates, organochlorines and amitraz, and BME/CTVM2, derived from acaricide-susceptible ticks. When studying the action of the same product on BME/CTVM6 cells infected with Ehrlichia minasensis, there was a clear reduction in percentage of infected cells of nearly two-thirds following spilanthol analogue treatment. In conclusion, the results clearly demonstrated that the use of the spilanthol alkyne analogue could be a promising strategy to control ticks.
The results obtained in the present study confirmed that the crude ethanolic extract obtained from the flowers, leaves and stem of Acmella oleracea has acaricidal potential against males and females of Amblyomma cajennense ticks. The lethal concentration of 50% (LC50) was stablished: 17.6335 mg/mL for semi-engorged females and 29.4534 mg/mL for males. The males of A. cajennense ticks when exposed to concentrations of 6.2; 12.5 and 25 mg/mL of the A. oleracea ethanolic extract presented severe morphological and ultrastructural damages in reproductive system, especially in the secretory cells of the accessory gland complex. In the case of females, when they were exposed to concentrations of 3.1; 6.2 and 12.5 mg/mL alterations in their reproductive system was observed. The alterations were mainly in oocytes in the early stages of development (I and II). The data obtained with the use of the alkyne analogue of spilanthol showed that it was able to reduce the viability and change the morphology of two tick cell lines obtained from Rhipicephalus microplus: BME/CTVM6 derived from ticks resistant to organophosphates, organochlorines and amitraz, and BME/CTVM2, derived from acaricide-susceptible ticks. When studying the action of the same product on BME/CTVM6 cells infected with Ehrlichia minasensis, there was a clear reduction in percentage of infected cells of nearly two-thirds following spilanthol analogue treatment. In conclusion, the results clearly demonstrated that the use of the spilanthol alkyne analogue could be a promising strategy to control ticks.
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Palavras-chave
Morfologia, Carrapato, Toxicologia, Histologia, Técnicas de cultura de células, Carrapatos, Controle químico natural, Toxicidade, Espilantol, Linhagens celulares de carrapatos, Ticks, Natural chemical control, Toxicity, Spilanthol, Tick cell lines