Phytochemistry, anti-tick, repellency and anti-cholinesterase activities of Cupressus sempervirens L. and Mentha pulegium L. combinations against Hyalomma scupense (Acari: Ixodidae)

Abstract

The adulticidal, larvicidal, and repellent effects of Cupressus sempervirens, Mentha pulegium, and their combination (C. sempervirens and M. pulegium) against Hyalomma scupense were investigated, as well as their putative mode of action. The evaluation on H. scupense was performed with the adult immersion test at concentrations ranging from 2.5–20 mg/mL and the larval packet test from 0.625 to 20 mg/mlL. The same concentrations were used for combined oils. Essential oils were obtained using hydrodistillation and then analyzed using GC–MS. The following major components were identified: α-pinene (56.89 %) and δ-3-Carene (15.61 %) for C. sempervirens, while pulegone (70.50 %) and cis-Menthone (18.26 %) for M. pulegium. At 20 mg/mL concentration, C. sempervirens had (94.40 %) acaricide action and inhibited the egg from hatching, however at 10 mg/mL, it had 100 % larvicidal activity. Adulticidal and larvicidal activities of M. pulegium oil reached to 87.19 % and 81.02 % respectively, at 20 mg/mL concentration. The highest acaricidal property against H. scupense was exhibited by combination oils with minimum LC50 values of 1.76 mg/mL on adultes and 0.60 mg/mL on larvae. The repellent activities were 100, 95.80 and 100 %, at the 20 mg/mL concentration used in 6 h, for C. sempervirens, M. pulegium and mixture oil respectively. Our findings revealed that the mixture of C. sempervirens and M. pulegium, at the ratio 1:1 (v: v) of each oil, showed high synergistic effect (SF > 1) and the use of combination oil (C. sempervirens 50 %: M. pulegium 50 %) is more toxic against H.scupense. Furthermore, the volatile oils examined revealed significant inhibition of H.scupense acetylcholinesterase activity AChE.Based on the findings of the present framework, these essential oils have the potential to be applied as substitute for synthetic acaricides in the management of H.scupense bovine ticks.