Hydroalcoholic extract of Caryocar brasiliense Cambess. leaves affect the development of Aedes aegypti mosquitoes.

Hevilem Letícia Moura do Nascimento Morais,Ranielly Araújo Nogueira,Nêuton Silva-Souza,João Gustavo Mendes Rodrigues,Maria Gabriela Sampaio Lira,Tássio Rômulo Silva Araújo Luz,Teresinha de Jesus Aguiar dos Santos Andrade,Talita Carneiro Feitosa,Guilherme Silva Miranda,Nerilson Marques Lima

doi:10.1590/0037-8682-0176-2020

Abstract

INTRODUCTION: Curtailing the development of the aquatic immature stages of Aedes aegypti is one of the main measures to limit their spread and the diseases transmitted by them. The use of plant extracts is a promising approach in the development of natural insecticides. Thus, this research aimed to characterize the inhibitory effect of the hydroalcoholic extract of Caryocar brasiliense leaves on the emergence of adult A. aegypti and the main substances that constitute this extract. METHODS: C. brasiliense leaf extract was prepared by ethanol (70%) extraction. Bioassays using L3 larvae were performed at concentrations of 200, 300, 400, and 500 ppm. We identified the major secondary metabolites present in this extract, and performed toxicity tests on an off-target organism, Danio rerio.RESULTS: We observed a significant delay in the development of A. aegypti larvae mainly at a concentration of 500 ppm, and estimated an emergence inhibition for 50% of the population of 150 ppm. Moreover, the C. brasiliense leaf extracts exhibited low toxicity in D. rerio. The main compounds found in the extract were quercetin, violaxanthin, myricetin3-O-hexoside, methyl-elagic-3-arabinose acid, and isoquercitrin. CONCLUSIONS: Herein, we demonstrate the inhibition of mosquito development by the hydroalcoholic extract of C. brasiliense and suggest substances that may act as active principles.

Highlights

Curtailing the development of the aquatic immature stages of Aedes aegypti is one of the main measures to limit their spread and the diseases transmitted by them
The present study showed that L3 larvae of A. aegypti failed to develop into mosquitoes when exposed to the hydroalcoholic extract of C. brasiliense leaves, it did not promote larval mortality
The growth regulatory activity of bioproducts can render them as promising insecticides, because affecting the aquatic evolutionary stages may reduce the number of future adults, suggesting that these insects will need a longer time for a new generation to complete their life-cycle[27]

Summary

Introduction

Curtailing the development of the aquatic immature stages of Aedes aegypti is one of the main measures to limit their spread and the diseases transmitted by them. We identified the major secondary metabolites present in this extract, and performed toxicity tests on an off-target organism, Danio rerio. Results: We observed a significant delay in the development of A. aegypti larvae mainly at a concentration of 500 ppm, and estimated an emergence inhibition for 50% of the population of 150 ppm. While there is no effective vaccine yet for Zika and Chikungunya, and the vaccination tests for Dengue remain without satisfactory results, the main methods to combat these arboviruses are focused on the immature aquatic forms of the mosquito vector. Morais HLMN et al - Caryocar brasiliense leaf extract affects the development of Aedes aegypti. A promising alternative is the use of natural compounds with insecticidal effects, as these substances generally do not harm the environment, and exhibit low toxicity to off-target organisms[9,10]. As plants produce many chemical compounds during metabolism (secondary metabolites), extracts and essential oils from different plant structures are promising alternatives for the sustainable combat of A. aegypti[11,12]

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