Abstract
Essential oil (EO) of Origanum vulgare L. was hydrodistilled and analysed using gas chromatography-flame ionization detection and gas chromatography-mass spectrometry. The monoterpenes, carvacrol (61.2%), γ-terpinene (9.6%), thymol (8.3%), and p-cymene (5.7%) were identified. Oil-in-water nanoemulsion was prepared and characterized from the EO through a green procedure. Botanicals had a remarkable mosquitocidal and effectively inhibited acetylcholinesterase activity of Aedes aegypti. The nanoemulsion at 40 µg/ml caused 100% adult and larval mortality after 12 h. At 80 µg/ml, percentage mortality caused by EO products ranged between 55.11-100% for larvae, and 63.0 -100%. for adults After 24 h exposure, LC50's ranged between 13.2 and 75.7 µg/ml against larvae, and between 10.1 and 36.0 µg/ml against adults. The lethal time (LT50) decreased with nanoemulsion, EO and carvacrol. Test products were safe towards the non-target aquatic species, Gambusia affinis and Diplonychus indicus. Results recommend test botanicals as natural alternatives to control Ae. aegypti.