In vitro acaricidal effects of essential oils against Rhipicephalus microplus via bioinformatics targeting of...

The tick Rhipicephalus (Boophilus) microplus poses a significant threat to animal health in tropical and subtropical regions, causing substantial economic losses in the meat and dairy industries. This study evaluated the potential of 20 essential oils as acaricidal agents, combining in vitro assays and in silico analyses to predict toxicity and efficacy. In the in vitro tests, the oils were assessed for their ability to reduce tick oviposition. The best results were observed at a 6 % concentration, with Eucalyptus citriodora showing the highest reduction (96.5 %), followed by Betula lenta (88.9 %), Amyris balsamifera (71.3 %), and Cinnamomum cassia (47.1 %). At a 3 % concentration, Amyris balsamifera (67.6 %) and Betula lenta (4.6 %) also showed significant efficacy, while the 1 % concentration had a limited impact on reducing oviposition, not meeting the legal efficacy criterion (>95 %). Concurrently, in silico analyses were conducted using the SwissDock platform to predict the molecular interactions of natural compounds with specific biological targets. The results revealed the free binding energy (estimated ΔG) and the amino acid residues involved in the interactions, allowing for the comparison of the compounds' affinity with reference drugs. The data indicated that some compounds present in the essential oils demonstrated considerable target affinity, suggesting a promising mechanism of action against the tick's reproductive cycle. These findings highlight the potential of essential oils as natural alternatives for controlling Rhipicephalus (Boophilus) microplus, especially at higher concentrations. However, the efficacy at lower concentrations and the toxicity in host animals need further investigation before practical application.