Seasonal variation in the chemical composition and larvicidal activity against Aedes aegypti of essential oils from Vitex gardneriana Schauer

The seasonal variation in essential oils from leaves of Vitex gardneriana Schauer was studied. Analysis of the chemical composition showed the presence of 3 monoterpenes, 2 non-oxygenated (alpha-pinene and beta-pinene) and 1 oxygenated (eucalyptol), and 24 sesquiterpenes, 21 non-oxygenated and 3 oxygenated. The main compound, 6.9-guaiadiene, presented the highest concentrations in October (30.15%), January (28.86%) and February (22.73%); cis-calamenene had the highest concentrations in December (35.62%), April (34.92%), November (34.63%) and March (33.57%); and caryophyllene oxide possessed the highest concentrations in September (16.68%), January (15.06%) and August (14.39%). Additionally, essential oils extracted in January (LC50 78.3 mu g/mL), March (LC50 44.1 mu g/mL), April (LC50 47.9 mu g/mL), May (LC50 28.0 mu g/mL), July (LC50 43.5 mu g/mL), August (LC50 62.0 mu g/mL) and December (LC50 84.3 mu g/mL) exhibited significant larvicidal activity against third instar larvae of Aedes aegypti. (C) 2019 SAAB. Published by Elsevier B.V. All rights reserved.