title: Chemical composition, larvicidal evaluation, and adult repellency of endemic Greek Thymus essential oils against the mosquito vector of West Nile virus.
abstract: The volatile metabolites of Greek wild growing Thymus leucospermus and Thymus teucrioides subsp. candilicus were determined by gas chromatography and gas chromatography-mass spectrometry. The monoterpene hydrocarbon p-cymene (64.2%) dominated T. leucospermus oil, followed by γ-terpinene (7.9%), thymol (4.8%), and borneol (4.7%), whereas the most abundant constituents in T. teucrioides subsp. candilicus oil were p-cymene (25.5%), γ-terpinene (19.0%), thymol (18.8%), borneol (5.7%), and α-pinene (5.7%). The larvicidal and repellent activities of the analyzed essential oils were tested on Culex pipiens larvae and adults, respectively. Additionally, the main metabolite of the essential oils, p-cymene was tested against C. pipiens adults in order to define the affiliation between p-cymene and the repellent properties of the oil. The essential oils of T. leucospermus and T. teucrioides subsp. candilicus provided repellency 78.1% and 72.9%, respectively, statistically equal to the reference product icaridin. The compound p-cymene showed almost no repellent activity. The essential oil of T. leucospermus presented lower larvicidal activity (LC(50) = 34.26 mgl(-1)) against C. pipiens third-fourth instar larvae while T. teucrioides subsp. candilicus was the most active with an estimated LC(50) value of 23.17 mgl(-1).
authors.affiliation: Department of Pharmacognosy and Chemistry of Natural Products, School of Pharmacy, University of Athens, Panepistimioupoli Zographou, 157 71 Athens, Greece.
authors.forename: Danae
authors.initials: D
authors.lastname: Pitarokili
authors.forename: Antonios
authors.initials: A
authors.lastname: Michaelakis
authors.forename: George
authors.initials: G
authors.lastname: Koliopoulos
authors.forename: Athanassios
authors.initials: A
authors.lastname: Giatropoulos
authors.forename: Olga
authors.initials: O
authors.lastname: Tzakou
mesh_terms: D000818:Animals; D003465:Culex / Q000187:drug effects*; D005260:Female; D008401:Gas Chromatography-Mass Spectrometry; D007302:Insect Repellents / Q000737:chemistry / Q000302:isolation & purification / Q000494:pharmacology*; D007306:Insecticides / Q000737:chemistry / Q000302:isolation & purification / Q000494:pharmacology*; D019686:Lamiaceae / Q000737:chemistry*; D007814:Larva / Q000187:drug effects; D009822:Oils, Volatile / Q000737:chemistry / Q000302:isolation & purification / Q000494:pharmacology*; D016019:Survival Analysis
chemical_list: D007302:Insect Repellents; D007306:Insecticides; D009822:Oils, Volatile