Background: There is a worldwide interest in metal nanoparticles synthesized by various
chemical reactions for use in biomedical applications. These processes exhibit a broad range
of toxicity in non-target organisms. To avoid chemical toxicity, green synthesis of metal nanoparticles
is proposed as a cost-effective and eco-friendly alternative. Aloe vera (A. vera) leaf extract
is a medicinal agent with multiple properties, including antibacterial effects. Its constituents include
lignin, pectin and hemicellulose, which can be used in the reduction of silver ions to produce
silver nanoparticles (AgNPs).
Objective: The study aimed at the use of naturally occurring compounds as a reducing and stabilizing
agent for the biosynthesis of nanoparticles and investigation of the insecticidal activity of
these compounds against Musca domestica (M. domestica) larvae.
Methods: Phytochemical analysis of A. vera gel extract was done and the phytochemical components
were identified by Gas Chromatography–Mass Spectrometry (GC-MS) analysis. AgNPs and
encapsulated Chitosan Nanoparticles (CsNPs) were prepared by an eco-friendly method using A.
vera gel extract as a reducing and stabilizing agent. A. vera-AgNPs and A. vera encapsulated
CsNPs were characterized using Ultraviolet-visible spectrophotometer (UV–vis spectrum),
Transmission Electron Microscopy (TEM), Fourier-Transform Infrared Spectroscopy (FTIR) and
X-ray Diffraction (XRD). Then the insecticidal activity of these compounds was investigated
against late second instar larvae of the house fly.
Results: The most active ingredients identified by GC-MS analysis were Terpene and Sesquiterpene
hydrocarbons. The synthesized AgNPs were spherical with an average size of about 12-75
nm, as revealed by TEM. While encapsulated CsNPs ranged between 34-75 nm and the shape
seemed spherical with dark parts confirming the encapsulated plant extract. FTIR and XRD results
confirmed the successful encapsulation of the gel extract within the chitosan nanoparticles.
Results proved the insecticidal potential of the tested compounds against M. domestica larvae, and
the relative potency of encapsulated CsNPs was nearly 148.51 times more potent than A. vera
crude extract whereas AgNPs was nearly 40.65 times more potent than A. vera crude extract. Furthermore,
a prolongation of larval duration and reduction in the percentage pupation and adult
emergence were observed.
Conclusion: Overall, green-synthesized silver and chitosan nanoparticles have the potential for
application as a biopesticide for house fly population control through the use of a safer and costeffective
approach. |
