Phytochemical screening, acaricidal activity, and in silico analysis of Commiphora swynnertonii extracts against Rhipicephalus decoloratus and Rhipicephalus microplus

Ticks remain major constraints to livestock production due to increasing resistance to conventional acaricides, necessitating alternative plant-based control strategies. This study evaluated the chemical composition, acaricidal activity, and potential mechanisms of Commiphora swynnertonii stem bark and exudate extracts against Rhipicephalus decoloratus and Rhipicephalus microplus . Phytochemical profiling was conducted using Gas Chromatography Mass Spectrometry (GC–MS), while acaricidal activity was assessed through larval and adult immersion bioassays. Molecular mechanisms were explored using homology modelling and molecular docking targeting acetylcholinesterase (AChE). GC–MS analysis identified 96 phytochemicals, predominantly terpenoids, steroids, and other lipophilic compounds. The extracts exhibited significant concentration and time dependent mortality (p < 0.05), with dichloromethane stem bark extracts showing the highest efficacy. In larvae, LC 50 andLC 90 values were 2.78 and 20.21 mg/mL for R. decoloratus and 5.54 and 38.60 mg/mL for R. microplus respectively. In adults, LC 50 and LC 90 values were 6.62 and 44.31 mg/mL and 8.80 and 45.47 mg/mL, respectively. Homology modelling of AChE was performed using Anopheles gambiae templates due to the absence of resolved tick structures. Molecular docking revealed strong binding affinities of several phytochemicals toward AChE, often exceeding the reference acaricide chlorfenvinphos. Notably, 3,17-dioxo-11-α-hydroxyandrostane-1,4-diene (−10.1 kcal/mol) and 2-furanmethanol, tetrahydro-α,α,5-trimethyl-5-(4-methyl-3-cyclohexen-1-yl) (−9.7 kcal/mol) showed the strongest interactions. Overall, these findings provide insights into the mechanism of AChE inhibition and highlight C. swynnertonii as a promising source of botanical acaricides for tick control.