The acaricide action of jambu (Acmella oleracea): study of the effects on morphophysiology of male and female reproductive systems of Amblyomma cajennense (Fabricius , 1787 ) ( Acari: Ixodidae ) ticks

Author(s)

Luís Adriano Anholeto

• Document type: Doctoral Thesis
• Press: Rio Claro. 2019-06-11.
• Institution: Universidade Estadual Paulista (Unesp). Instituto de Biociências. Rio Claro
• Defense date: 2019-05-27
• Advisor: Maria Izabel Souza Camargo; Patrícia Rosa de Oliveira

Abstract

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. (AU)

• FAPESP's process: 15/01496-5 - The acaricide action of Jambu (Acmella oleracea): I. Study of the effects on morphophysiology of male and female reproductive systems of Amblyomma cajennense (Fabricius, 1787) (Acari: Ixodidae)
• Grantee: Luís Adriano Anholeto
• Support Opportunities: Scholarships in Brazil - Doctorate