Antimicrobial Activity of Silver and Gold Nanoparticles Prepared by Photoreduction Process with Leaves and Fruit Extracts of Plinia cauliflora and Punica granatum

Abstract

The increased number of resistant microbes generates a search for new antibiotic methods. Metallic nanoparticles have emerged as a new platform against several microorganisms. The nanoparticles can damage the bacteria membrane and DNA by oxidative stress. The photoreduction process is a clean and low-cost method for obtaining silver and gold nanoparticles. This work describes two original insights: (1) the use of extracts of leaves and fruits from a Brazilian plant Plinia cauliflora, compared with a well know plant Punica granatum, and (2) the use of phytochemicals as stabilizing agents in the photoreduction process. The prepared nanoparticles were characterized by UV-vis, FTIR, transmission electron microscopy, and Zeta potential. The antimicrobial activity of nanoparticles was obtained with Gram-negative and Gram-positive bacteria, particularly the pathogens Staphylococcus aureus ATCC 25923; Bacillus subtilis ATCC 6633; clinical isolates of methicillin-resistant Staphylococcus aureus (MRSA) and Enterococcus faecalis; Escherichia coli ATCC 25922; Escherichia coli O44:H18 EAEC042 (clinical isolate); Klebsiella pneumoniae ATCC 700603, Salmonella Thiphymurium ATCC 10231; Pseudomonas aeruginosa ATCC 27853; and Candida albicans ATCC 10231. Excellent synthesis results were obtained. The AgNPs exhibited antimicrobial activities against Gram-negative and Gram-positive bacteria and yeast (80–100%), better than AuNPs (0–87.92%), and may have the potential to be used as antimicrobial agents.

Antibacterial Potential of Gold Nanoparticles Synthesized From Leaf Extract of Syzygium cumini Against Multidrug-Resistant Urinary Tract Pathogens

“…Our findings of antibacterial activity revealed that escalating the concentrations of ScAu-NPs increases the zone diameter. Similar findings were observed by other researchers when they examined the antibacterial activity of plant-mediated AuNPs against clinical and American Type Culture Collection (ATCC) strains and concluded substantial antibacterial activity [24,25]. MIC of ScAu-NPs was also calculated to determine the least concentration that inhibits the growth of uropathogens.…”

Green Synthesis of Silver Nanoparticles Using Salvia verticillata and Filipendula ulmaria Extracts: Optimization of Synthesis, Biological Activities, and Catalytic Properties

“…Intensive bands at 1602 and 1616 cm −1 were observed in the FTIR spectra of SVE and FUE, respectively. This broad band in the 1600 and 1700 cm −1 region could be attributed to the C=C stretching vibration of aromatic rings, as well as the C=O group of amides, esters, or C=O group on the C ring of flavones [ 28 , 29 , 30 , 31 ]. These intensive bands were also noticed at similar positions in the SVAgNP and the FUAgNP FTIR spectra (1623 and 1605 cm −1 , respectively), but attenuated.…”

Evaluation of Plant-Based Silver Nanoparticles for Antioxidant Activity and Promising Wound-Healing Applications

“…These changes confirmed the involvement of plant extract metabolites in AgNP formation. OH and CO groups present in plant extract play a key role in the reduction and stabilization of NPs …”