Toxicity, Chemical Composition and Molecular Docking of Sweet Orange and Lemon Cypress Essential Oils Tested against Tribolium castaneum (Coleoptera: Tenebrionidae)

Saad, Nora A.; Rady, Magda H.; Darwish, Ahmed A.; Heikal, Ibrahim H.; El-Deeb, Sara E.; Yones, Mona S.; Farag, Shaimaa M.

doi:10.21608/ejchem.2025.368550.11461

Toxicity, Chemical Composition and Molecular Docking of Sweet Orange and Lemon Cypress Essential Oils Tested against Tribolium castaneum (Coleoptera: Tenebrionidae)

Articles in Press

Document Type : Original Article

Authors

¹ Department Of Plant Protection , Central Laboratory Of Organic Agriculture , Agriculture Research Centre

² Department of Entomology , Faculty of Science, Ain shams University

³ Department of Plant Protection , Faculty of Agriculture , Benha University , Qalyubia , Egypt

⁴ Agriculture Applications Department, National authority for remote sensing and space sciences (NARSS), Cairo, Egypt

10.21608/ejchem.2025.368550.11461

Abstract

The red flour beetle, Tribolium castaneum (Herbst) (Coleoptera: Tenebrionidae) is one of the most destructive pests attacking stored grains all over the world. The problems related with using synthetic chemical insecticides to control such insect have strongly promoted the need for application alternative safe compounds such as plant essential oils (EOs). This study aimed to assess the contact and fumigant toxicity of two EOs extracted from sweet orange fruit peels and lemon cypress leaves against the adult stage of T. castaneum. Both EOs were found to be effective against T. castaneum adult. Probit analysis revealed that, sweet orange EO was more effective than lemon cypress in contact and fumigation bioassays. Gas Chromatography and Mass Spectrometry analysis (GC-MS) showed that, sweet orange oil mainly consisted of D-limonene (97.38%) while, sabinene (19.14%) and 3-Cyclohexen-1-ol,4-methyl-1-(1-methylethyl)-(cas) (12.17%) were the major constituents of lemon cypress EO. The expected interaction between the main compounds of the two tested oils and acetyl choline esterase (AChE) enzyme of T. castaneum were proved by computational docking programs. Major identified compounds showed varying levels of binding affinities to AChE, where; (R)-1-isopropyl-4-methylcyclohex-3-en-1-ol (BE= -6.27 kcal/ mol) and sabinene (BE= -5.63 kcal/ mol) in lemon cypress EO had the highest and lowest binding affinity, respectively. This study suggested that these major compounds combined with each other in both oils could be responsible for the insecticidal and AChE inhibitory potentials of both EOs.

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