Larvicidal Effects of <i>Cymbopogon commutatus</i> Essential Oil and Its Based Nanoformulations on <i>Culex pipiens</i> : Chemical Profiling and Physicochemical Characterization

Cymbopogon commutatus has been used as an ingredient in the manufacturing of soap and mosquito repellent. Herein, the chemical profiling of the C. commutatus aerial parts essential oil (CCEO) was constructed on the basis of the multiplex of GC-MS and nuclear magnetic resonance (NMR). Four nanoformulations-EO nanoemulsions (CCEO@NE), chitosan-coated (CSNPs@NE), silver nanoparticle-loaded (AgNPs@NE), and iron oxide-loaded (Fe₂O₃NPs@NE)-were formulated. The larvicidal effects of CCEO, its major component, and its nanoformulations were evaluated on Culex pipiens. Twenty-seven components (99.77%)-including monoterpenes (78.36%) and sesquiterpenes (21.41%)-were tentatively identified, including geraniol (67.49%) and geranyl acetate (3.52%) as predominant constituents. Geraniol was isolated and confirmed via NMR spectroscopic analysis. The nanoformulations exhibited diverse characteristics, with particle sizes spanning from 81.28 ± 6.17 nm (CCEO@NE) to 128.67 ± 6.96 nm (Fe₂O₃NPs@NE) and encapsulation efficiencies ranging from 72.57% ± 4.05% (Fe₂O₃NPs@NE) to 83.73% ± 6.69% (CCEO@NE). Zeta potentials ranged from -21.38 ± 5.18 mV (AgNPs@NE) to +14.39 ± 2.19 mV (CSNPs@NE), indicating variations in surface charge stability. CCEO and geraniol showed the highest larvicidal effects, recording LC₅₀ of 263.96 and 226.41 ppm, respectively, after 48 h of exposure. Nanoformulations showed latent effects and inhibitory activity in pupation and fly emergence. Consequently, CCEO and its nanoformulations may present good alternatives for controlling C. pipiens.