Chemical Composition and Acaricidal Activity of the Essential Oils of Some Plant Species ofLamiaceaeandMyrtaceaeagainst the Vector of Tropical Bovine Theileriosis:Hyalomma scupense(syn.Hyalomma detritum)

Abstract

The present study aimed to investigate the acaricidal properties of six essential oils. They were extracted from some plant species (Lamiaceae and Myrtaceae) using the technique of hydrodistillation with the Clevenger apparatus. The chemical compositions of the essential oils under study were determined by gas chromatography–mass spectrometer (GC-MS). An Adult Immersion Test (AIT) and a Larval Immersion Test (LIT) were used to evaluate the acaricidal activity of these essential oils against the adults and larvae of Hyalomma scupense. GC-MS analysis showed the major constituents of each essential oil: 25.49% of α-thujone (lavender); 46.82% of carvacrol (oregano); 78.78% of carvacrol (thyme); 40.27% of 1,8-cineole (blue gum); 17.45% of p-cymene (river red gum); and 26.96% of 1,8-cineole (rosemary). The biotests on the essential oils revealed that they inhibit the reproduction of H. scupense engorged females at a rate of 100 % with doses of 0.781 μl/ml of rosemary, 1.562 μl/ml of thyme, 3.125 μl/ml of lavender and oregano, and 6.250 μl/ml of blue gum and river red gum. After a treatment that lasted for 24 hours, essential oils showed a larvicidal activity with respective values of lethal concentrations (LC): LC50, LC90, and LC95 (0.058, 0.358, and 0.600 μl/ml for thyme; 0.108, 0.495, and 0.761 μl/ml for rosemary; 0.131, 0.982, and 1.740 μl/ml for oregano; 0.155, 2.387, and 5.183 μl/ml for blue gum; 0.207, 1.653, and 2.978 μl/ml for river red gum; and 0.253, 2.212, and 4.092 μl/ml for lavender). This is the first report on the acaricidal activity of these essential oils against H. scupense. The results obtained showed that the essential oils with chemotype carvacrol, 1,8-cineole, α-thujone, and p-cymene are highly acaricidal, and they can be used for ticks control. However, further studies on their toxicity in nontarget organisms are required.

A review on Hyalomma species infestations on human and animals and progress on management strategies

“…(Tarragon) Diethyl ether (DE), ethyl acetate (EA), hexane, and ethanol extracts of aerial parts H. dromedarii Against larvae LC 50 = 0.0952 μg/μl (DE), 0.0636 μg/μl (EA), 0.0437 μg/μl (hexane) and 0.252 μg/μl (ethanol) Abdel-Shafy et al., 2007 Azadirachta indica (Meliaceae) NeemAzal F (Commercial product prepared from seed) H. excavatum Significant decrease in eggs hatching rate; LC 50 = 1.0 % (newly hatched larvae), 0.5 % (unfed larvae) and unfed adults (1.6–3.2 %) Abdel-Shafy and Zayed, 2002 A. indica A Juss (Meliaceae) Neem oil and azadirachtin essential oil formulation H. dromedarii Significant effect on larva feeding, molting of nymph and molt ability at 2.5 μg/mL azadirachtin; Against adult contact LC50 is > 40.7 μg cm −2 and against larvae dipping LC 50 = 5.0 μg/mL Al-Rajhy et al., 2003 Calotropis procera (Asclepiadaceae) A cardiac glycosidal (cardenolide) extract H. dromedarii Against larvae contact LC 50 = 9.63 μg/cm 2 and dipping LC 50 = 1.096 μg/mL Al-Rajhy et al., 2003 Cymbopogon winterianus Ethanolic extracts of leaves H. anatolicum Against larvae LC 50 (leaves extracts) = 0.14 % Singh et al., 2014 Digitalis purpurea L. (Scrophulariaceae) A cardiac glycosidal (digitoxin) extract H. dromedarii Against larvae contact LC 50 = 4.08 μg/cm 2 and dipping LC 50 = 0.410 μg/mL. Al-Rajhy et al., 2003 Eucalyptus camaldulensis Dehnh (river red gum) Essential oil from leaves and flowering tops through hydrodistillation H. scupense 100 % inhibition of reproduction of female at 6.250 μl/ml; Against larvae LC 50 = 0.207 μl/ml, LC 90 = 1.653 μl/ml and LC 95 = 2.978 μl/ml) Djebir et al. (2019) E. globulus Labill (blue gum) Essential oil from leaves and flowering tops through hydrodistillation H. scupense 100 % inhibition of the reproduction in female at 6.250 μl/ml; Against larvae LC 50 = 0.155 μl...…”

“… Al-Rajhy et al., 2003 Eucalyptus camaldulensis Dehnh (river red gum) Essential oil from leaves and flowering tops through hydrodistillation H. scupense 100 % inhibition of reproduction of female at 6.250 μl/ml; Against larvae LC 50 = 0.207 μl/ml, LC 90 = 1.653 μl/ml and LC 95 = 2.978 μl/ml) Djebir et al. (2019) E. globulus Labill (blue gum) Essential oil from leaves and flowering tops through hydrodistillation H. scupense 100 % inhibition of the reproduction in female at 6.250 μl/ml; Against larvae LC 50 = 0.155 μl/ml, LC 90 = 2.387 μl/ml and LC 95 = 5.183 μl/ml Djebir et al. (2019) E. globoidea dichloromethane extract of plant H. rufipes Significant repellent effects against adults (30–40 % of extract up to 120 min) Magano et al.…”

“…(2014) Haplophyllum tuberculatum (Rutaceae) Essential oils from aerial parts H. dromedarii Against larvae LC 50 = 0.5 % Abdel-Shafy et al. (2007) Lavandula stoechas L. (lavender) Essential oil from leaves and flowering tops through hydrodistillation H. scupense 100 % inhibition of reproduction at 3.125 μl/ml; Against larvae LC 50 = 0.253 μl/ml, LC 90 = 2.212 μl/ml, and LC 95 = 4.092 μl/ml Djebir et al. (2019) Mesembryanthemus forsskale (Aizoaceae) Diethyl ether (DE), ethyl acetate (EA), hexane, and ethanol extracts of aerial parts H. dromedarii Against larvae LC 50 = 0.611 μg/μl (DE), 1.646 μg/μl (EA), 0.294 μg/μl (hexane) and 0.380 μg/μl (ethanol).…”

“… Abdel-Shafy et al. (2007) Rosmarinus officinalis L. (rosemary) Essential oil from leaves and flowering tops through hydrodistillation H. scupense 100 % inhibition of reproduction at 0.781 μl/ml; Against larvae LC 50 = 0.108 μl/ml, LC 90 = 0.495 μl/ml, and LC 95 = 0.761 μl/ml Djebir et al. (2019) Saturejathymbra L. (Lamiaceae) Volatile essential oil collected from arial part of plant at flowering stage through hydrodistillation H. marginatum 100 % adult tick mortality in 3 h at 40 μl/L Cetin et al.…”

“…(2008) Tagetes minuta L. (Asteraceae) Essential oil from aerial parts and flowers H. rufipes Repellent EC 50 for male ticks = 0.072 mL/mL and for female = 0.070 mL/mL; Significant number of nymphs (60%) delayed in moulting Nchu et al. (2012) Thymus capitatus L. (thyme) Essential oil from leaves and flowering tops through hydrodistillation H. scupense 100 % inhibit the reproduction in femaleat 1.562 μl/ml; Against larvae LC 50 = 0.058 μl/ml, LC 90 = 0.358 μl/ml, and LC 95 = 0.600 μl/ml Djebir et al. (2019) Vitex negundo Ethanolic extracts of leaves and roots H. anatolicum Against larvae LC 50 (root extract) = 1.27 % and (leaves extract) = 0.011 % Singh et al.…”