Natural Mosquito Repellent Compounds from Asian weaver ant Oecophylla smaragdina

Abstract Insect repellents play a crucial role in preventing vector-borne diseases and protecting crops from insect pests. However most commercial repellents are synthetic and pose environmental and health risks. In the continual process of search for insect-based repellents of natural origin, ant species have emerged as promising candidates due to their bioactive chemical secretions. Oecophylla smaragdina , known for its aggressive territorial behavior, secretes compounds through specialized glands. Gas Chromatography-Mass Spectrometry (GC-MS) analysis of abdominal glandular secretions of major workers of O. smaragdina identified several volatile compounds with different properties, from which compounds like Naphthalene; 2-ethyl-1-dodecanol, Dodecanol,3,7,11-trimethyl, 2,4-Di-tert-butylphenol known for their insect repellent properties were chosen. These compounds were further screened using molecular docking against mosquito odorant-binding proteins (OBP1, OBP4, OBP22, OBP47), which are crucial for host detection. Among the tested compounds, 2,4-Di-tert-butylphenol exhibited the strongest binding affinity across all three OBPs, with the highest docking score observed for OBP1 (-8.9 kcal/mol). Naphthalene also showed notable binding, especially with OBP1 (-8.1 kcal/mol), followed by OBP 47 (-7.4 kcal/mol). OBP1 and OBP47 interacted with both ligands, suggesting their broader binding potential. Overall, 2,4-Di-tert-butylphenol and Naphthalene demonstrated the most promising binding profile, indicating its potential role in olfactory communication in Oecophylla smaragdina . The study highlights the effectiveness of O. smaragdina glandular secretions as a source of eco-friendly, biologically derived repellents, supporting the development of sustainable alternatives to harmful synthetic chemicals.