Phytochemical and acaricidal analysis of lavender (Lavandula angustifolia) and sage (Salvia officinalis) essentials oils against Rhipicephalus microplus ticks: An in vitro and in vivo study

Abstract

Based on earlier reports on acaricidal and repellent properties of Lavandula angustifolia and Salvia officinalis plants against various ectoparasites, including tick species, the present study was carried out using these essential oils (EOs) to explore the possibility of developing a potent herbal anti-tick formulation to manage cattle tick Rhipicephalus microplus. The EOs were evaluated against different life stages of ticks to provide a complete solution for tick control. The oils were also subjected to GC-MS analysis for their phytochemical constituents, which revealed a total of 125 compounds in lavender oil, predominantly consisting of alpha-pinene (10.24 %), D-limonene (7.50 %), 1,3,6-octatriene, 3,7-dimethyl-(Z) (6.48 %) and linalool (6.43 %), while sage oil contained 92 compounds, with linalool and linalyl acetate with an area percentage of 11.03 % and 9.83 % being the most abundant. All the treated engorged ticks were killed at 5 and 10 % EOs of L. angustifolia and S. officinalis with a significant reduction in oviposition in different concentrations. Both EOs were also effective against 83-100 % larvae at a 5 % dose in larval immersion test. Additionally, the study also examined the hatching inhibition of R. microplus eggs treated with both essential oils and achieved 100 % hatching inhibition at 5 % concentration. The repellency index (RI) indicated effective repellent activity with L. angustifolia having 0.0 ± 0.0 and S. officinalis 0.6 ± 0.15 at RI 10 %. Hematological and biochemical parameters showed no significant changes and no skin irritation in topically treated animals, suggesting the oils' safety for livestock use. The in vivo efficacy of both EOs was over 80 % after 72 h under patch treatment of naturally infested cattle. This research highlights the potential of lavender and sage essential oils as viable alternatives to develop an eco-friendly solution for tick management.

Keywords: Acaricide; Botanicals; Cattle; Ectoparasite; Phytochemistry; Plants; Repellent.