Mechanism of Larvicidal Activity of Antimicrobial Silver Nanoparticles Synthesized Using Garcinia mangostana Bark Extract

In this present investigation, we used an inexpensive method for the synthesis of silver nanoparticles (AgNPs) using Garcinia mangostana bark. The phyto-assisted AgNPs further characterized using scanning electron microscope for morphology and the elemental composition was detected via energy dispersive X-ray analysis. The domain size was characterized with the help of X-ray diffraction and UV-Vis spectrophotometric analysis for surface plasmon resonance. The possible functional groups were identified with the help of Fourier transform infrared spectroscopy. Antibacterial properties of nanoparticles were evaluated against Escherichia coli, Bacillus subtilis, Staphylococcus aureus, Bacillus cereus and Klebsiella pneumoniae, using agar well diffusion method. Ultimately, the mosquitocidal activity of silver nanoparticles was assessed in the laboratory against fourth instar larvae of Aedes aegypti with LC50 of 5.93 mg L-1 which shows the potential larvicidal effect. To find out the mode of action for larvicidal activity, Agarose gel electrophoresis was carried out. We hypothesize that the toxicity of AgNPs against dengue vectors may be attributed to the small size of these AgNPs, which allows passage through the insect cuticle and into individual cells where they interfere with molting and other physiological processes.