GC(FID) and GC–MS Composition and Mosquito-Repellent Activity of the Leaf Essential Oil of Citrus limon L. (Rutaceae) from Côte d’Ivoire

Objectives: This study aimed to characterize the chemical composition of the essential oil (EO) from the leaves of Citrus limon L. and to evaluate its repellent activity against Anopheles gambiae. Methods: The EO was obtained by hydrodistillation with a yield of 0.70% and analyzed by gas chromatography with flame ionization detection (GC–FID) and gas chromatography–mass spectrometry (GC–MS). Repellency tests, conducted according to the WHO standard protocol, involved the application of ointments at 5% and 10% on guinea pigs exposed to adult mosquitoes. Findings: The EO was obtained with a yield of 0.70%. A total of 22 constituents were identified, representing 93.45% of the oil, dominated by limonene (45.36%), monoterpenes (87.23 %), and a smaller fraction of sesquiterpenes (3.67%). At 10%, it offers a Complete Protection Time (CPT = 100 %) of 4 hours compared to 3 hours 30 minutes for the natural reference substance (C. citratus) against adult female Anopheles mosquitoes (14 days). Novelty: Considering its extractive value and long-lasting repellent properties (100 % for 4 hours and 98.12 % for 7 hours), Citrus limon L. should be recommended for the development of natural, biodegradable, long-lasting alternative repellents for skin application. Keywords: Citrus limon L., Essential oil, GC–MS, Limonene, Repellent activity, Anopheles gambiae