Novel synthesis of gold nanoparticles using Artemisia vulgaris L. leaf extract and their efficacy of larvicidal activity against dengue fever vector Aedes aegypti L

Abstract

The Aedes aegypti L. mosquito transmits dengue and yellow fever, which cause millions of death every year. Dengue is a mosquito-borne viral disease that has rapidly spread worldwide particularly in countries with tropical and subtropical climates areas. The present study denotes a simple and eco-friendly biosynthesis of gold nanoparticles using Artemisia vulgaris L. leaf extract as reducing agent. The synthesized gold nanoparticles were characterized by UV-Visible Spectroscopy, X-Ray Diffraction (XRD), Fourier Transform Infrared Spectroscopy (FT-IR), Dynamic Light Scattering (DLS), Zeta Potential (ZP), Transmission Electron Microscopy (TEM) and Energy Dispersive X-ray Spectroscopy (EDX). Solid state ¹³C NMR was utilized to confirm the presence of larvicidal compound Beta caryophyllene in the synthesized AuNPs. Larvicidal activity of the synthesized AuNPs was measured against A. aegypti over 12 and 24h exposure periods and compared with essential oil in various concentrations (25ppm, 50ppm, 100ppm, 200ppm and 400ppm). After a 12h exposure period, the larvicidal activity of 3^rd instar larva by AuNPs showed LC₅₀=156.55ppm and LC₉₀=2506.21ppm, while and essential oil displayed LC₅₀=128.99ppm and LC₉₀=1477.08ppm. Larvicidal activity of 4^th instar larva by AuNPs showed LC₅₀=97.90ppm and LC₉₀=1677.36ppm, while essential oil displayed LC₅₀=136.15ppm and LC₉₀=2223.55ppm. After a 24h of exposure period, larvicidal activity of 3^rd instar larva by AuNPs showed LC₅₀=62.47ppm and LC₉₀=430.16ppm and essential oil showed LC₅₀=111.15ppm and LC₉₀=1441.51ppm. The larvicidal activity of 4^th instar larva and AuNPs displayed LC₅₀=43.01ppm and LC₉₀=376.70ppm and for essential oil LC₅₀=74.42ppm, LC₉₀=858.36ppm. Histopathology of A. aegypti with AuNPs for 3^rdand 4^th stage larvae after 24h exposure at the highest mortality concentration (400ppm) showed that the area of the midgut, epithelial cells and cortex were highly affected. The present findings demonstrate that the biosynthesis of AuNPs using A. vulgaris leaf extracts could be an eco-friendly, safer nanobiopesticide and treatment against A. aegypti which could be used to combat of dengue fever.

Keywords: Aedes aegypti L.; Artemisia vulgaris L.; Dengue; Gold nanoparticles; Larvicidal activity.