Tackling the growing threat of dengue: Phyllanthus niruri-mediated synthesis of silver nanoparticles and their mosquitocidal properties against the dengue vector Aedes aegypti (Diptera: Culicidae)

Abstract

Mosquitoes are vectors of devastating pathogens and parasites, causing millions of deaths every year. Dengue is a mosquito-borne viral infection found in tropical and subtropical regions around the world. Recently, transmission has strongly increased in urban and semiurban areas, becoming a major international public health concern. Aedes aegypti (Diptera: Culicidae) is the primary vector of dengue. The use of synthetic insecticides to control Aedes mosquitoes lead to high operational costs and adverse nontarget effects. In this scenario, eco-friendly control tools are a priority. We proposed a novel method to synthesize silver nanoparticles using the aqueous leaf extract of Phyllanthus niruri, a cheap and nontoxic material. The UV-vis spectrum of the aqueous medium containing silver nanostructures showed a peak at 420 nm corresponding to the surface plasmon resonance band of nanoparticles. SEM analyses of the synthesized nanoparticles showed a mean size of 30-60 nm. EDX spectrum showed the chemical composition of the synthesized nanoparticles. XRD highlighted that the nanoparticles are crystalline in nature with face-centered cubic geometry. Fourier transform infrared spectroscopy (FTIR) of nanoparticles exhibited prominent peaks 3,327.63, 2,125.87, 1,637.89, 644.35, 597.41, and 554.63 cm(-1). In laboratory assays, the aqueous extract of P. niruri was toxic against larval instars (I-IV) and pupae of A. aegypti. LC50 was 158.24 ppm (I), 183.20 ppm (II), 210.53 ppm (III), 210.53 ppm (IV), and 358.08 ppm (pupae). P. niruri-synthesized nanoparticles were highly effective against A. aegypti, with LC50 of 3.90 ppm (I), 5.01 ppm (II), 6.2 ppm (III), 8.9 ppm (IV), and 13.04 ppm (pupae). In the field, the application of silver nanoparticles (10 × LC50) lead to A. aegypti larval reduction of 47.6%, 76.7% and 100%, after 24, 48, and 72 h, while the P. niruri extract lead to 39.9%, 69.2 % and 100 % of reduction, respectively. In adulticidal experiments, P. niruri extract and nanoparticles showed LC50 and LC90 of 174.14 and 6.68 ppm and 422.29 and 23.58 ppm, respectively. Overall, this study highlights that the possibility to employ P. niruri leaf extract and green-synthesized silver nanoparticles in mosquito control programs is concrete, since both are effective at lower doses if compared to synthetic products currently marketed, thus they could be an advantageous alternative to build newer and safer tools against dengue vectors.

Toxicity on Dengue Mosquito Vectors Through Myristica fragrans-Synthesized Zinc Oxide Nanorods, and Their Cytotoxic Effects on Liver Cancer Cells (HepG2)

“…In India, the reports of natural vertical transmission of dengue viruses are scarce, although the field evidence supporting vertical transmission as a means of persistence has been obtained [4]. Currently, there is no specific treatment for dengue, even if the development of a vaccine is in progress [5], thus its prevention and control solely depends on effective vector control measures [6]. The trend for dengue vector control in most tropical regions has shifted from relying solely on insecticides to an integrated approach involving biological control, source reduction and environmental management through community participation [7].…”

Nanofabrication of Graphene Quantum Dots with High Toxicity Against Malaria Mosquitoes, Plasmodium falciparum and MCF-7 Cancer Cells: Impact on Predation of Non-target Tadpoles, Odonate Nymphs and Mosquito Fishes

“…For both species, eggs were transferred to laboratory conditions [27 ± 2°C, 75-85 % R.H., 14:10 (L:D) photoperiod] and placed in 18 9 13 9 4 cm plastic containers containing 500 mL of tap water, waiting for larval hatching [44,45]. Larvae were reared in the containers and fed daily with a mixture of crushed dog biscuits (Pedigree, USA) and hydrolyzed yeast (Sigma-Aldrich, Germany) at a 3:1 ratio (w:w).…”

“…In latest years, a growing number of nanocomposites have been studied for their toxic activity against young instars of several mosquito vectors (e.g. [11,25,36,37,44,45,[77][78][79][80]). A good example is the larvicidal activity of Sargassum muticum-synthesized Ag nanoparticles against larval instars and pupae of A. aegypti, A. stephensi, and C. quinquefasciatus [81].…”

An Overview of Naturally Synthesized Metallic Nanoparticles

“…Similarly, mosquitoborne viral disease called dengue was found mostly in tropic and sub-tropic region around the world. Estimation by World Health Organization (WHO) states that there are about 50-100 million dengue infection are prevalent worldwide (Suresh et al, 2015). A vector of Wuchereria species called Culex quinquefasciatus was responsible for causing lymphatic Filariasis which are wide spread in the tropical region with 120 million people infected and 40 million people are under clinical manifestation (Veerakumar et al, 2013).…”

“…Due to the development of insecticides resistance, biological magnification, serious effect on environmental quality and destruction of nontarget organism, the vector controlling methods involving chemical insecticides are becoming less effective (Suganya et al, 2014). The use of artificial insecticides in order to control mosquito-borne vector especially Aedes leads to high cost and harmful non-target effect (Suresh et al, 2015). Cancer, which is grouped as the uncontrolled development of cells, is one of the serious causes of death throughout the world.…”