Toxicity, repellency, and anti-cholinesterase activities of bioactive molecules from clove buds Syzygium aromaticum L. as an ecological alternative in the search for control Hyalomma scupense (Acari: Ixodidae)

Dhouha Alimi; Azhar Hajri; Selim Jallouli; Hichem Sebai

doi:10.1016/j.heliyon.2023.e18899

Toxicity, repellency, and anti-cholinesterase activities of bioactive molecules from clove buds Syzygium aromaticum L. as an ecological alternative in the search for control Hyalomma scupense (Acari: Ixodidae)

Heliyon. 2023 Aug 5;9(8):e18899. doi: 10.1016/j.heliyon.2023.e18899. eCollection 2023 Aug.

Authors

Dhouha Alimi¹, Azhar Hajri¹, Selim Jallouli², Hichem Sebai¹

Affiliations

¹ Laboratory of Functional Physiology and Valorization of Bio-resources (LR23ES08), Higher Institute of Biotechnology of Beja, Habib Bourguiba Street, Box 382, 9000, Beja, University of Jendouba, Tunisia.
² Laboratory of Bioactive Substances, Centre of Biotechnology of Borj Cedria, Box 901 Hammam-Lif 2050, Tunisia.

Abstract

Introduction: The goal of the current study is to evaluate the acaricidal and repellent properties of the ethanolic extract, essential oil, and primary component eugenol from Syzygium aromaticum against Hyalomma scupense cattle ticks. Their potential mechanisms of action were also examined, using an in vitro assay.

Methods: Clove essential oil was extracted using hydrodistillation technique. Gas chromatography-mass spectrometry (GC-MS) was performed to identify the chemical composition of clove. To evaluate the adulticidal, ovicidal, larvicidal and repellent proprieties of clove essential oil, eugenol and ethanolic extract on H. scupense, in vitro assays were performed using the adult immersion test (AIT), the ovicidal test, the larval packet test (LPT), the filter paper test and anti-acetylcholinesterase (AChE) activity.

Results: After treatment, eugenol, the primary phytoconstituent of clove oil, which accounts for 97.66% of the whole oil, had 99.22% acaricide activity and inhibited egg hatching at a concentration of 10 mg/mL. Eugenol and clove essential oil showed potent adulticidal effect at high concentrations (10 mg/mL), achieving 100 and 93.76% mortality, respectively. The ethanolic extract exhibited moderate activity. At high concentration, the larvicidal activity of S. aromaticum oil, eugenol, and ethanolic extract were 100, 100, and 77.18%, respectively. In filter paper experiments, when tested at the concentration 5 mg/mL; eugenol showed the longest repellent effect up to 6 h. We also found that eugenol was the most active AChE inhibitor (IC₅₀ = 0.178 mg/mL). Nevertheless, additional investigations are required to confirm the accurate mechanism and the relevance of clove in practical application.

Conclusion: Overall, our research indicated that, because its effectiveness as acaricide, S. aromaticum essential oil and its phytoconstituent eugenol may offer an alternative source for the control of H. scupense cattle ticks.

Keywords: Acetylecholinesterase; Hyalomma scupense; Larvicidal; Ovicidal; Repellent; Syzygium aromaticum.