Biosynthesis and characterization of silver nanoparticles prepared using seeds of Sisymbrium irio and evaluation of their antifungal and cytotoxic activities

Abstract

Abstract Recent studies have shown that green synthesis of silver nanoparticles (AgNPs) and their application in the control of phytopathogenic fungi is a burgeoning field. Sisymbrium irio (Si) (London rocket) is a well-known weed that grows abundantly in Saudi Arabia from February to May. The present study is concerned with the rapid synthesis of silver nanoparticles from the aqueous seed extract of Si) in the presence of sunlight. The biosynthesized Si-AgNPs were characterized using UV-Visible spectroscopy (UV-Vis), energy dispersive X-ray (EDX) microanalysis, dynamic light scattering analysis (DLS), transmission electron microscopy (TEM), and Fourier transform infrared spectroscopy analysis (FTIR). The UV-Vis spectrum revealed a prominent surface plasmon resonance (SPR) absorption band (∼439 nm) characteristic of AgNPs. As revealed by TEM analysis, the Si-AgNPs were predominantly spheroidal in shape and measured between 4 and 51 nm, while the Z average of nanoparticles was 94.81 nm as revealed by the DLS spectrum. The FTIR spectrum displayed peaks related to important functional groups (amines, phenols, carboxylic acids, flavonoids, aromatic compounds, and esters) that aid in the reduction, encapsulation, and stability of AgNPs. The Si-AgNPs were further investigated against a panel of potent fungal phytopathogens that included Alternaria alternata, A. brassicae, Fusarium solani, F. oxysporum, and Trichoderma harzianum. The cytotoxic activity of the biosynthesized nanoparticles against human cervical cancer cell lines (HeLa) was also tested. Si-AgNPs at 80 µg·mL−1 demonstrated a marked reduction in mycelial growth and spore germination. Similarly, Si-AgNPs exhibited dose-dependent cytotoxic activity against the HeLa cell line, with an IC50 value of 21.83 ± 0.76 µg·mL−1. The results of the present study demonstrate the robust cytotoxic and antifungal activities of Si-AgNPs. Based on the findings, Si-AgNPs can be exploited to design formulations that can effectively act as anticancer agents, controlling the proliferation of cancer cells while also combating fungal phytopathogens. However, future research to understand their toxicity mechanisms is needed.