AUTHOR=Ullah Sami , Khalid Rimsha , Rehman Muhammad F. , Irfan Muhammad I. , Abbas Azhar , Alhoshani Ali , Anwar Farooq , Amin Hatem M. A. 

TITLE=Biosynthesis of phyto-functionalized silver nanoparticles using olive fruit extract and evaluation of their antibacterial and antioxidant properties

JOURNAL=Frontiers in Chemistry

VOLUME=11

YEAR=2023

URL=https://www.frontiersin.org/journals/chemistry/articles/10.3389/fchem.2023.1202252

DOI=10.3389/fchem.2023.1202252

ISSN=2296-2646

ABSTRACT=<p>The green synthesis of nanomaterials is of utmost interest as it offers an eco-friendly approach over chemical synthetic routes. However, the reported biosynthesis methods are often time-consuming and require heating or mechanical stirring. The current study reports a facile one-pot biosynthesis of silver nanoparticles (AgNPs) mediated by olive fruit extract (OFE) and sunlight irradiation of only 20 s. OFE acts as both a reducing and a capping agent for the formation of OFE-capped AgNPs (AgNPs@OFE). The as-synthesized NPs were systematically characterized by UV-vis spectrometry, Fourier transform infrared (FTIR) spectroscopy, scanning electrochemical microscopy with energy-dispersive X-ray (SEM-EDX), X-ray diffraction (XRD), dynamic light scattering (DLS), and cyclic voltammetry. SEM images confirmed the successful formation of monodispersed spherical AgNPs@OFE of approximately 77 nm. FTIR spectroscopy suggested the involvement of functional groups of phytochemicals from the OFE in the capping and reduction of Ag<sup>+</sup> to Ag. The particles revealed excellent colloidal stability as evidenced from the high zeta potential (ZP) value (−40 mV). Interestingly, using the disk diffusion method, AgNPs@OFE revealed higher inhibition efficiency against Gram-negative bacteria (<italic>Escherichia coli</italic>, <italic>Klebsiella oxytoca</italic>, and extensively drug-resistant (XDR) <italic>Salmonella typhi</italic>) than Gram-positive bacteria (<italic>Staphylococcus aureus</italic>), with <italic>Escherichia coli</italic> showing the highest inhibition zone of 27 mm. In addition, AgNPs@OFE exhibited maximum potent antioxidant scavenging potential against H<sub>2</sub>O<sub>2</sub>, followed by DPPH, O<sub>2</sub><sup>−</sup>, and OH<sup>−</sup> free radicals. Overall, OFE can be considered an effective source for the sustainable production of stable AgNPs with potential antioxidant and antibacterial activities for biomedical applications.</p>