Green Synthesis of Gold and Silver Nanoparticles from Plant Extracts and Their Possible Applications as Antimicrobial Agents in the Agricultural Area

Abstract

Currently, metal nanoparticles have varied uses for different medical, pharmaceutical, and agricultural applications. Nanobiotechnology, combined with green chemistry, has great potential for the development of novel and necessary products that benefit human health, environment, and industries. Green chemistry has an important role due to its contribution to unconventional synthesis methods of gold and silver nanoparticles from plant extracts, which have exhibited antimicrobial potential, among other outstanding properties. Biodiversity-rich countries need to collect and convert knowledge from biological resources into processes, compounds, methods, and tools, which need to be achieved along with sustainable use and exploitation of biological diversity. Therefore, this paper describes the relevant reported green synthesis of gold and silver nanoparticles from plant extracts and their capacity as antimicrobial agents within the agricultural field for fighting against bacterial and fungal pathogens that can cause plant, waterborne, and foodborne diseases. Moreover, this work makes a brief review of nanoparticles’ contribution to water treatment and the development of “environmentally-friendly” nanofertilizers, nanopesticides, and nanoherbicides, as well as presenting the harmful effects of nanoparticles accumulation in plants and soils.

Green synthesis of metal nanoparticles using microorganisms and their application in the agrifood sector

“…Green synthesis of MtNPs using microorganisms is a promising and environmentally friendly approach for agricultural applications such as nanofertilizers, nanopesticides and nanobiosensors. Given their potential widespread use in the future it is likely that large volumes of MtNPs produced by different methods will enter ecosystems [ 172 ]. Despite the favorable physical and chemical properties of MtNPs, the complexity of soil-crop ecosystems means that the environmental behaviors of these nanoparticles are not yet fully predictable after use, and this remains an important challenge [ 173 ].…”

“…The nanoscale dimensions of MtNPs, which determines many of their beneficial properties, can potentially also increase their potential adverse effects [ 172 ]. The toxicity of MtNPs is influenced by various factors such as solubility and their binding specificity to biological sites [ 175 ].…”

“…Biogenic MtNPs can be potentially toxic directly to plants, to plant-related beneficial microbes and eventually to human. Therefore, when using MtNPs directly in crops special attention must be paid to the interaction between nanoparticles and the treated plants [ 25 , 172 , 177 ]. The interaction between MtNPs and plants leads to numerous physiological, morphological and genotoxic changes that must be fully understood to ensure effective application of nanotechnology in agriculture.…”

Green Silver and Gold Nanoparticles: Biological Synthesis Approaches and Potentials for Biomedical Applications

“…Plant materials generate nanoparticles by taking up, utilizing, accumulating and using different nutrients [ 58 ]. The general protocol for a typical plant-mediated metal nanoparticle synthesis requires first the collection and the purification of the plant part of interest [ 59 ]. The plant piece is then dried and powdered.…”

“…Silver nanoparticles have also been produced with aqueous-alcoholic solutions of roasted coffee ( Coffea arabica ), green tea and black tea [ 54 , 58 , 59 ]. The authors found that caffeine and theophylline in the extracts were responsible for stabilizing the produced nanoparticles.…”