Larvicidal and pupicidal evaluation of silver nanoparticles synthesized using Aquilaria sinensis and Pogostemon cablin essential oils against dengue and zika viruses vector Aedes albopictus mosquito and its histopathological analysis

Abstract

Mosquitoes pose a threat to humans and animals, causing millions of deaths every year. Vector control by effective eco-friendly pesticides of natural origin is a serious issue that requires urgent attention. The employment of green-reducing extracts for nanoparticles biosynthesis in a rapid and single-step process represents a promising strategy. In this study, silver nanoparticles (AgNPs) were biofabricated using an essential oil of Aquilaria sinensis (AsEO) and Pogostemonis Herba essential oil of Pogostemon cablin (PcEO) in one step and cost-effective manner. UV-vis spectrophotometry, Fourier transform infrared spectroscopy, scanning electron microscopy, transmission electron microscopy, X-ray diffraction analysis and energy-dispersive X-ray spectroscopy were used to confirm the AgNPs formation and their biophysical characterization. The larvicidal and pupicidal toxicity of AsEO, PcEO and biosynthesized AgNPs were evaluated against larvae and pupae of the dengue and Zika virus vector Aedes albopictus. Compared to the tested essential oils, the biofabricated AgNPs showed the highest toxicity against larvae and pupae of Ae.albopictus. In particular, the LC values of AsEO ranged from 44.23 (I) to 166 (pupae), LC values of PcEO ranged from 32.49 (I) to 90.05(IV), LC values of AsEO-AgNPs from 0.81 (I) to 1.12 (IV) and LC values of PcEO-AgPNs from 0.85 (I) to 1.19 (IV). Furthermore, histological analysis of the midgut cells of the control and treated larvae exhibited that the epithelial cells and brush border were highly affected by the fabricated AgNPs compared to the essential oils (AsEO and PcEO). Overall, the A. sinensis and P. cablin essential oils fabricated AgNPs have a potential of application as a biopesticide for mosquito control through safer and cost-effective approach.

Larvicidal Activity of Synthesized Silver Nanoparticles from Curcuma zedoaria Essential Oil against Culex quinquefasciatus

“…The appearance of light brown color was caused by the excitation of surface plasmon vibrations in silver nanoparticles [27] at 415 nm, which predicted the formation of AgNPs. Previous reports have shown evidence that similar color changes caused the agitation of the Surface Plasmon Resonance (SPR) peak of the synthesized AgNPs [15,21,32]. The maximum absorption peak of ZEO-AgNPs was found at 415 nm, which indicates the fabrication of AgNPs [33,34,35].…”

“…The silver nanoparticles (AgNPs) were synthesized by the essential oil reduction method of Ga’al et al [21] with some modification. The C. zedoaria essential oil (ZEO) was used as both a stabilizing and reducing agent.…”

Bioactivities of patchoulol and phloroacetophenone from Pogostemon cablin essential oil against three insects

“…[18] Smelling a unique woody odor, the essential oil of P. cablin, usually known as patchouli oil, is of great industrial importance [19] and has been reported showing bioactivities against insect pests. There are some reports recording the insecticidal activities of P. cablin against mosquito vectors, [20] cockroach, [21] termites, [22,23] armyworm, [24] and ants, [25,26] as well as repellent effects on termites, [22,23] sweetpotato whitefly, [27] urban ants [25] and the cockroach. [21] And a recent paper [26] reported that P. cablin essential oil showed behavioral impairment on leaf-cutting ants.…”

Biocontrol of mosquito vectors through herbal-derived silver nanoparticles: prospects and challenges

“…Positive charge, acidic environment of midgut, and nanosize of silver particles are suitable for easy internalization and mucoadhesion of the above-discussed AgNPs in insect gut (Jiang et al 2015). Silver nanoparticle-treated larvae of A. albopictus revealed severe lesions in midgut epithelium layer including vacuolization of the cell, degradation of the membrane, broken brush border, rupture of cells, cytopathological variations, destruction of epithelial cells, and degradation of nuclei (Ga'al et al 2018). Similar effects, such as apical swelling in the midgut, reduction of intracellular contact within cells, and degeneration of nuclei were also observed in A. aegypti after treatment of Hedychium coronarium Koenig rhizome-derived AgNPs (Kalimuthu et al 2017b).…”