One-step synthesis of polydispersed silver nanocrystals using Malva sylvestris: an eco-friendly mosquito larvicide with negligible impact on non-target aquatic organisms

Abstract

The synthesis of eco-friendly nanoparticles is evergreen branch of nanoscience with a growing number of biomedical implications. In this study, we investigated the synthesis of polydisperse and stable silver nanoparticles (AgNP) using a cheap leaf extract of Malva sylvestris (Malvaceae). Bio-reduced AgNP were characterized by 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). The acute toxicity of M. sylvestris leaf extract and green-synthesized AgNP was evaluated against larvae of the malaria vector Anopheles stephensi, the dengue vector Aedes aegypti and the filariasis vector Culex quinquefasciatus. Compared to the leaf aqueous extract, AgNP showed higher toxicity against A. stephensi, A. aegypti, and C. quinquefasciatus with LC 50 values of 10.33, 11.23, and 12.19 μg/mL, respectively. Greensynthesized AgNP were found safer to non-target organisms Diplonychus indicus and Gambusia affinis, with respective LC 50 values ranging from 813.16 to 1044.52 μg/mL. Overall, this research firstly shed light on the mosquitocidal potential of M. sylvestris, a potential bio-resource for rapid, cheap and effective synthesis of polydisperse and highly stable silver nanocrystals.

Green-Synthesized Mosquito Oviposition Attractants and Ovicides: Towards a Nanoparticle-Based “Lure and Kill” Approach?

“…In latest years, a growing number of evidences have been provided about the larvicidal efficacy of plant-fabricated nanolarvicides, while only moderate efforts focused on their ovicidal potential and oviposition manipulation activity [17,36]. Each plant material containing unique bioactivity including repellent, larvicidal, ovicidal, and adulticidal activity, thus their efficacy of nanosynthetical routes varies from species to species and also according to the tested plant parts [1,2,37,38]. Combination of nanoparticles with bioactive principles bestows improved efficiency.…”

“…Nowadays, moderate knowledge is available about the acute toxicity of mosquitocidal nanoparticles towards non-target aquatic species [17]. Recently, Govindarajan et al [38] reported that the biotoxicity of M. sylvestris aqueous extract and green-synthesized AgNPs was negligible also on non-target organisms D. indicus and G. affinis, since the toxicity treatments achieved LC 50 ranging from 813.16 to 10,459.13 lg/mL. In addition, the biotoxicity of B. cristata aqueous extract and green-synthesized AgNPs was evaluated on non-target organisms D. indicus, A. bouvieri, and G. affinis with LC 50 ranging from 633.26 to 8595.89 lg/ mL, respectively [10].…”

Malva: Food, Medicine and Chemistry

“…Synthesis of nanoparticles of precious metals (or their oxides) using Malva species extracts has been reported by many groups. [140][141][142]172,188,216,[303][304] In all these reports, aqueous extracts of leaves or flowers of the plants were used. The major quality that enables this kind of uses and reactions is the fact that these extracts are rich in flavonoids and anthocyanins.…”

“…303 Leaves aqueous extract and AgNO3 were used to prepare AgNP's and their mosquito larvicide activity was tested. These AgNP's have almost no effect on other aquatic organisms 304 …”

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

“…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].…”