Effect of essential oils on native and recombinant acetylcholinesterases of Rhipicephalus microplus

Authors: DOS SANTOS, EVERTON - Universidade Federal Do Maranhao; DOS SANTOS BEZERRA, WALLYSON - Universidade Federal Do Maranhao; Temeyer, Kevin; Perez De Leon, Adalberto - Beto; COSTA-JUIOR, LIVIO - Universidade Federal Do Maranhao; DOS SANTOS SOARES, ALEXANDRA - Universidade Federal Do Maranhao

Submitted to: Brazilian Journal of Veterinary Parasitology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 2/28/2021
Publication Date: 5/28/2021
Citation: Dos Santos, E.G., Dos Santos Bezerra, W.A., Temeyer, K.B., Perez De Leon, A.A., Costa-Juior, L.M., Dos Santos Soares, A.M. 2021. Effect of essential oils on native and recombinant acetylcholinesterase of Rhipicephalus microplus. Brazilian Journal of Veterinary Parasitology. 30. Article e002221. https://doi.org/10.1590/S1984-29612021024.
DOI: https://doi.org/10.1590/S1984-29612021024

Interpretive Summary: The Southern Cattle Tick, Rhipicephalus microplus, is a serious pest and vector of fatal disease to cattle. Tick control has become increasingly difficult due to development of resistance to most chemical pesticides, highlighting the need for development of alternative tick control technologies. In addition, chemical pesticides often exhibit toxicity to other organisms and residues persist in the environment. Essential oils extracted from plants present one potential alternative to chemical pesticides. The present study aimed to evaluate the action of essential oils from five plant species on the activity of tick acetylcholinesterase (AChE) as a possible mechanism of action affecting ticks. The effect of the essential oils on enzyme activity was verified using an acetylcholinesterase inhibition test. Essential oils of Eucalyptus globulus, Citrus aurantifolia, Citrus aurantium var. dulcis that inhibited tick AChE extracted from tick larvae. Mentha piperita oil also inhibited tick AChE, but there was significant inhibition only at the highest concentration tested. The essential oil of Cymbopogon winterianus did not inhibit tick AChE but might be useful against ticks resistant to pesticides that target AChE. Additional studies are needed on the use and chemical components of essential oils as candidates for development of new acaricides.

Technical Abstract: This study reports the action of essential oils (EO) from five plants on the activity of native and recombinant acetylcholinesterases (AChE) from Rhipicephalus microplus. Enzyme activity of native susceptible AChE extract (S.AChE), native resistant AChE extract (R.AChE), and recombinant enzyme (rBmAChE1) was determined. An acetylcholinesterase inhibition test was used to verify the effect of the EO on enzyme activity. EO from Eucalyptus globulus, Citrus aurantifolia, Citrus aurantium var.dulcis inhibited the activity of S.AChE and R.AChE. Oils from the two Citrus species inhibited S.AChE and R.AChE in a similar way while showing greater inhibition on R.AChE. The oil from E. globulus inhibited native AChE, but no difference was observed between the S.AChE and R.AChE; however, 71% inhibition for the rBmAChE1 was recorded. Mentha piperita oil also inhibited S.AChE and R.AChE, but there was significant inhibition at the highest concentration tested. Cymbopogon winterianus oil did not inhibit AChE. Further studies are warranted with the oils from the two Citrus species that inhibited R.AChE because of the problem with R. microplus resistant to organophosphates, which target AChE. C. winterianus oil can be used against R. microplus populations that are resistant to organophosphates because its acaricidal properties act by mechanism(s) other than AChE inhibition.