One Pot Green Synthesis of Colloidal Silver Nanocrystals Using the Ventilago maderaspatana Leaf Extract: Acute Toxicity on Malaria, Zika Virus and Filariasis Mosquito Vectors

Mosquitoes act as a vector for most of the life-threatening diseases. The green synthesis of eco-friendly metal nanoparticles is a fast-growing branch of current nanoscience with a number of biomedical and entomological implications. Here, we have synthesized silver nanoparticles (AgNPs) by using a poorly studied Indian plant, Ventilago maderaspatana. The results recorded from UV–Visible spectrophotometry, Fourier transform infrared spectroscopy (FTIR), X-ray diffraction analysis (XRD), atomic force microscopy (AFM), scanning electron microscopy (SEM) and transmission electron microscopy (TEM) confirmed the quick synthesis of AgNPs. The toxic activity of V. maderaspatana leaf extract and biosynthesized AgNPs was evaluated against the malaria vector Anopheles stephensi, the Zika virus vector Aedes aegypti and the filariasis vector Culex quinquefasciatus. Compared to the leaf aqueous extract, AgNPs showed higher toxicity against A. stephensi, A. aegypti, and C. quinquefasciatus with LC50 values of 24.89, 26.92 and 29.24 μg/mL, respectively. A single treatment with AgNPs tested at 120, 150 and 180 μg/mL led to no egg hatchability. In adulticidal experiments, the maximum efficacy was observed on A. stephensi (LD50 = 41.19 μg/mL), followed by A. aegypti (LD50 = 44.85 μg/mL) and C. quinquefasciatus (LD50 = 48.94 μg/mL), respectively. V. maderaspatana extract and green fabricated AgNPs were found safer to non-target aquatic biocontrol organisms Anisops bouvieri, Diplonychus indicus and Gambusia affinis, with LC50 ranging from 1673 to 41,854 µg/ml.