Efeitos dos isômeros α-pineno e β-pineno na morfofisiologia dos oócitos de fêmeas semi-ingurgitadas de carrapatos Rhipicephalus microplus (Acari: Ixodidae)

Abstract

Pinenes are bicyclic monoterpenes that contain two constitutional isomers, α- and β-pinene. Both have diverse biological activities, such as fungicidal, insecticidal, antimicrobial and antibacterial action, among others. Thus, the objective of this research was to evaluate the effect of sublethal concentrations of the active ingredients α- and β-pinene, diluted in 2% Tween 80, on the morphology of the ovary of semi-engorged Rhipicephalus microplus female ticks. To do this, the ticks were immersed in different concentrations of each product for five minutes. After seven days, the animals were dissected to collect the ovaries. The material was processed and included in historesin, sectioned, stained and analyzed using histopathological and semiquantitative analysis. The morphological changes observed in the oocytes of individuals treated with both compounds were: cytoplasmic vacuolization, irregular shape of the oocytes, vacuolated nucleolus (ring-shaped nucleolus), fusion of granules, irregular basal lamina, basophilic accumulations, cytoplasmic disorganization, and irregular, thick and fragmented chorion. The semi-quantitative analysis showed significant differences between the distilled water control group and the groups treated with the highest concentrations of α-pinene and the lowest of β-pinene. Therefore, the results point to the potential of α- and β-pinene as possible compounds to be used in future acaricide formulations.