Green Synthesis, Characterization, and Antibacterial Properties of Silver Nanoparticles Obtained by Using Diverse Varieties of Cannabis sativa Leaf Extracts

Abstract

Cannabis sativa L. (hemp) is a plant used in the textile industry and green building material industry, as well as for the phytoremediation of soil, medical treatments, and supplementary food products. The synergistic effect of terpenes, flavonoids, and cannabinoids in hemp extracts may mediate the biogenic synthesis of metal nanoparticles. In this study, the chemical composition of aqueous leaf extracts of three varieties of Romanian hemp (two monoecious, and one dioecious) have been determined by Fourier-Transformed Infrared spectroscopy (FT-IR), high-performance liquid chromatography, and mass spectrometry (UHPLC-DAD-MS). Then, their capability to mediate the green synthesis of silver nanoparticles (AgNPs) and their pottential antibacterial applications were evaluated. The average antioxidant capacity of the extracts had 18.4 ± 3.9% inhibition determined by 2,2-diphenyl-1-picrylhydrazyl (DPPH•) and 78.2 ± 4.1% determined by 2,2′-azino-bis (3-ethylbenzothiazoline-6-sulfonic acid) diammonium salt (ABTS™) assays. The total polyphenolic content of the extracts was 1642 ± 32 mg gallic acid equivalent (GAE) L−1. After this, these extracts were reacted with an aqueous solution of AgNO3 resulting in AgNPs, which were characterized by UV−VIS spectroscopy, FT-IR, scanning electron microscopy (SEM-EDX), and dynamic light scattering (DLS). The results demonstrated obtaining spherical, stable AgNPs with a diameter of less than 69 nm and an absorbance peak at 435 nm. The mixture of extracts and AgNPs showed a superior antioxidant capacity of 2.3 ± 0.4% inhibition determined by the DPPH• assay, 88.5 ± 0.9% inhibition as determined by the ABTS•+ assay, and a good antibacterial activity against several human pathogens: Escherichia coli, Klebsiella pneumoniae, Pseudomonas fluorescens, and Staphylococcus aureus.

Green Synthesis of Silver Nanoparticles Using Natural Extracts with Proven Antioxidant Activity

“…In turn, Alternanthera tenella [ 24 ], Dendrophthoe falcate , and Datura inoxia [ 25 ] extracts appeared to be useful for the preparation of AgNPs inhibiting human breast cancer (MCF-7) cell migration. More recently, the usefulness of Cannabis sativa leaf extracts to mediate the green synthesis of AgNPs and their antibacterial activity against several human pathogens ( Escherichia coli , Klebsiella pneumoniae , Pseudomonas fluorescens , and Staphylococcus aureus ) have been proven [ 26 ]. An interesting application of plant-mediated AgNPs was demonstrated by Mondéjar-López et al [ 27 ].…”

Chemical and Biochemical Characterization of Essential Oils and Their Corresponding Hydrolats from Six Species of the Lamiaceae Family

“…As presented by other studies [59][60][61], the more hydrophilic compounds present in the samples (EOs and HDs) were better reproduced by the ABTS •+ assay than the DPPH • assay, which is more sensitive for samples containing phenolic compounds and derivates. The data suggested that using the ABTS •+ assay, we obtained higher values of the antioxidant activity of EOs and HDs compared to DPPH • assay.…”

Síntese e caracterização de nanopartículas de prata estabilizada em extrato de Struthanthus Flexicaulis Mart. (Erva-de-Passarinho)

“…Grafico1: Espectroscopia de UV-vis das AgNPS, obtidas por diferentes métodos de extração. Fonte: Autores (2021).…”

“…-42,73 ± 1,52 -22,00 ± 1,99 -25,37 ± 1,80 -28,10 ± 1,56 Tamanho Médio 25,94 ± 1,48 59,61 ± 0,6 45,54 ± 0,38 54,84 ± 0,22 PDI 0,581 ± 0,038 0,303 ± 0, 002 0,296 ± 0,007 0,299 ± 0,007 Fonte: Autores (2021). Graça (2015) descreve o método por infusão, como promissor para a síntese de nanopartículas de prata em extratos de…”