Mosquito Repellents of Natural Origins from Aromatic Plant-Derived Essential Oils: A Narrative Review

Abstract

Dengue, Zika, and chikungunya arboviral diseases pose serious threats to global public health, primarily transmitted by Aedes aegypti and Aedes albopictus. The conventional use of chemical insecticides to control these vectors is becoming increasingly ineffective due to rising insecticide resistance and environmental concerns. In response, essential oils (EOs) derived from aromatic plants have garnered growing interest as natural, eco-friendly alternatives, owing to their volatile bioactive compounds with broad-spectrum repellent and insecticidal properties. This review provides a critical overview of EO-based mosquito repellents, focusing on their botanical origins, chemical compositions, bioactivity profiles, and mechanisms of action. Notably, compounds such as monoterpenes (e.g., citronellal, thymol, and carvacrol) and sesquiterpenes (e.g., β-caryophyllene), particularly from plant families like Lamiaceae, Asteraceae, and Myrtaceae, have demonstrated significant repellent activity, sometimes comparable to synthetic agents like N,N-diethyl-meta-toluamide (DEET) under laboratory conditions. However, the high volatility of these compounds limits their long-term efficacy. To address this, advanced formulation technologies, including nanoemulsions, lipid-based carriers, polymeric microcapsules, and cyclodextrin complexes, have been developed to enhance EO stability and prolong their release profiles. Furthermore, emerging insights into their molecular mechanisms, such as inhibition of transient receptor potential ankyrin 1 (TRPA1), modulation of odorant-binding receptors, and disruption of olfactory signalling, shed new light on their repellent potential. Despite encouraging laboratory outcomes, further efforts in formulation standardisation, regulatory assessment, and field validation are essential to position EOs as viable, sustainable alternatives to synthetic repellents.