Development of nano-emulsions based on Ayapana triplinervis for the control of Aedes aegypti larvae

Abstract

Ayapana triplinervis is a plant species used in traditional medicine and in mystical-religious rituals by traditional communities in the Amazon. The aim of this study is to evaluate the larvicidal activity against A. aegypti of nano-emulsions containing essential oils from A. triplinervis morphotypes, and acute oral toxicity in non-target organism. Essential oils were identified and nano-emulsions were prepared using the low energy method. The mortality test of A. aegypti larvae was performed according to the protocol recommended by the World Health Organization, and toxicity in non-target mammals was performed according to the OECD. Phytochemical analyses indicated the major compounds (E)-Caryophyllene (45.93%) and Thymohydroquinone Dimethyl Ether (32.93%) in morphotype A, and in morphotype B, Thymohydroquinone Dimethyl Ether (84.53%) was found. Morphotype A essential oil nano-emulsion showed a particle size of 101.400 {+/-} 0.971 nm (PdI = 0.124 {+/-} 0.009 and ZP = -19,300 {+/-} 0.787 mV). Morphotype B essential oil nano-emulsion had a particle size of 104.567 {+/-} 0.416 nm (PdI = 0.168 {+/-} 0.016 and ZP = -27,700 {+/-} 1,307 mV). Histomorphological analyses showed the presence of inflammatory cells in the liver of animals treated with morphotype A essential oil nano-emulsion (MAEON) and morphotype B essential oil nano-emulsion (MBEON). Congestion and the presence of transudate with leukocyte infiltration in the lung of animals treated with MAEON were observed. The nano-emulsions containing essential oils of A. triplinervis morphotypes showed an effective nanobiotechnological product in the chemical control of A. aegypti larvae and safe for non-target mammals.