Seasonal variation in the chemical composition and biological activity of the essential oil of Mesosphaerum suaveolens (L.) Kuntze

In tropical countries, arboviruses are public health threats, especially those transmitted by Aedes aegypti mosquitoes. The prevention of such diseases is based on vector control. However, the compounds currently used have disadvantages such toxicity to humans and environment, so larvicide plants is a promising alternative. The purpose of this study is to determine the best season to harvest aerial parts of Mesosphaerum suaveolens (L.) Kuntze to obtain its essential oil, and evaluate the effects of seasons on chemical composition, larvicidal activity against A. aegypti, and toxicology against Artemia salina and Danio rerio using such essential oils and its major compounds. The gas chromatography-mass spectrometry analysis of essential oil samples performed at different times during a year, showed qualitative and quantitative variation in the chemical composition. 1,8-Cineole is the major compound in all seasons. The dry season had a higher yield. The essential oils showed activity against A. aegypti larvae, with lethal concentrations varying from 90.8 to 135.2 mu g/mL. Their major compounds present no activity up to the highest concentration tested (200 mu g/mL). The toxicity for A. salina and D. rerio was lower than for A. aegypti larvae, ranging from 94.6 to 215.7 mu g/mL. The results demonstrate potential of the essential oil of the aerial parts of M. suaveolens for the control of A. aegypti larvae, and evidence that the oil of the plant collected in the dry season is more promising for the control of the larvae and provides better yield.