title: Larvicidal potential of carvacrol and terpinen-4-ol from the essential oil of Origanum vulgare (Lamiaceae) against Anopheles stephensi, Anopheles subpictus, Culex quinquefasciatus and Culex tritaeniorhynchus (Diptera: Culicidae).
abstract: Mosquito-borne diseases represent a deadly threat for millions of people worldwide. However, the use of synthetic insecticides to control Culicidae may lead to resistance, high operational costs and adverse non-target effects. Nowadays, plant-borne mosquitocides may serve as suitable alternative in the fight against mosquito vectors. In this study, the mosquito larvicidal activity of Origanum vulgare (Lamiaceae) leaf essential oil (EO) and its major chemical constituents was evaluated against the malaria vectors Anopheles stephensi and An. subpictus, the filariasis vector Culex quinquefasciatus and the Japanese encephalitis vector Cx. tritaeniorhynchus. The chemical composition of the EO was analyzed by gas chromatography-mass spectroscopy. GC-MS revealed that the essential oil of O. vulgare contained 17 compounds. The major chemical components were carvacrol (38.30%) and terpinen-4-ol (28.70%). EO had a significant toxic effect against early third-stage larvae of An. stephensi, An. subpictus, Cx. quinquefasciatus and Cx. tritaeniorhynchus, with LC50 values of 67.00, 74.14, 80.35 and 84.93 μg/ml. The two major constituents extracted from the O. vulgare EO were tested individually for acute toxicity against larvae of the four mosquito vectors. Carvacrol and terpinen-4-ol appeared to be most effective against An. stephensi (LC50=21.15 and 43.27 μg/ml, respectively) followed by An. subpictus (LC50=24.06 and 47.73 μg/ml), Cx. quinquefasciatus (LC50=26.08 and 52.19 μg/ml) and Cx. tritaeniorhynchus (LC50=27.95 and 54.87 μg/ml). Overall, this research adds knowledge to develop newer and safer natural larvicides against malaria, filariasis and Japanese encephalitis mosquito vectors.
authors: Unit of Vector Control, Phytochemistry and Nanotechnology, Department of Zoology, Annamalai University, Annamalainagar 608 002, Tamil Nadu, India. Electronic address: drgovind1979@gmail.com.
authors: Marimuthu
authors: M
authors: Govindarajan
authors: Unit of Vector Control, Phytochemistry and Nanotechnology, Department of Zoology, Annamalai University, Annamalainagar 608 002, Tamil Nadu, India.
authors: Mohan
authors: M
authors: Rajeswary
authors: Regional Medical Research Centre, Nehru Nagar, Belgaum 590010, Karnataka, India.
authors: S L
authors: SL
authors: Hoti
authors: Department of Agriculture, Food and Environment, University of Pisa, via del Borghetto 80, 56124 Pisa, Italy. Electronic address: benelli.giovanni@gmail.com.
authors: Giovanni
authors: G
authors: Benelli
mesh_terms: D000818:Animals; D000852:Anopheles / Q000187:drug effects* / Q000254:growth & development; D003465:Culex / Q000187:drug effects* / Q000254:growth & development; D000081007:Cymenes; D008401:Gas Chromatography-Mass Spectrometry; D007194:India; D007306:Insecticides / Q000494:pharmacology*; D007814:Larva / Q000187:drug effects / Q000254:growth & development; D039821:Monoterpenes / Q000494:pharmacology*; D009822:Oils, Volatile / Q000494:pharmacology*; D031341:Origanum / Q000737:chemistry*; D018515:Plant Leaves / Q000737:chemistry; D013729:Terpenes / Q000494:pharmacology*
chemical_list: D000081007:Cymenes; D007306:Insecticides; D039821:Monoterpenes; D009822:Oils, Volatile; D013729:Terpenes; C034019:terpinenol-4; C073316:carvacrol
keywords: Arbovirus; Eco-friendly larvicides; Filariasis; Malaria; Mosquito vectors; Plant-borne mosquitocides