Lippia gracilis essential oil in β-cyclodextrin inclusion complexes: an environmentally safe formulation to control Aedes aegypti larvae.

Background: One of the most efficient ways to prevent arboviruses, such as dengue fever, yellow fever, chikungunya and Zika, is by controlling their vector, the Aedes aegypti. Because this vector is becoming resistant to most larvicides used, the development of new larvicides should be considered. β-Cyclodextrin (β-CD) complexes have been investigated as an interesting way of enabling the use of essential oils in water as larvicides. This study comprised the development of Lippia gracilis essential oil (LGEO) and β-CD inclusion complexes for control of Ae. aegypti.

Results: Thermal analysis clearly showed the formation of complexes using kneading and co-evaporation methods. Gas chromatography analysis showed that kneading without co-solvent (KW) gave the highest content (∼ 15%) of the LGEO major component. Moreover, KW showed that the complex had a 50% lethal concentration (LC ; 33 ppm) lower than that of pure LGEO (39 ppm); in other words, complexing LGEO with β-CD improved the larvicidal activity. In addition, LGEO complexed with β-CD (KW) was not harmful to non-target organisms at the concentrations needed to control Ae. aegypti larvae.

Conclusion: The inclusion complex with LGEO was a feasible formulation, being economically viable, easy-to-apply and without impact on non-target organisms and, therefore, is a potential alternative larvicide for Ae. aegypti control. © 2018 Society of Chemical Industry.