Comparative influence of Punica granatum organ-specific biosynthesis of silver nanoparticles on yield, structure, antioxidant, and antimicrobial activity

Abstract

ABSTRACT The growing concern over microbial spoilage and postharvest losses in horticultural commodities has intensified the search for sustainable preservation strategies. In this study, silver nanoparticles (AgNPs) were biosynthesized using metabolically profiled extracts from different organs of Punica granatum , including flowers (AgNPs-FE), leaves (AgNPs-LE), peels (AgNPs-PE), and seeds (AgNPs-SE), to comparatively evaluate the influence of organ-specific phytochemical composition on nanoparticle properties and bioactivity. Metabolomic profiling revealed distinct distributions of phenolics, tannins, and flavonoids across the organs, which contributed to nanoparticle synthesis and stabilization. The synthesized nanoparticles were characterized using X-ray diffraction (XRD), UV-visible spectroscopy, Fourier-transform infrared (FTIR) spectroscopy, transmission electron microscopy (TEM), scanning electron microscopy (SEM), and electron dispersion spectroscopy (EDS). These tools confirmed the formation of predominantly spherical AgNPs with crystallite sizes ranging from 15.34 to 18.63 nm, while mean particle sizes ranged between 10.67 and 17.05 nm. AgNPs-PE exhibited the highest yield, while AgNPs-SE demonstrated superior antibacterial activity against foodborne pathogens, including Staphylococcus aureus, Escherichia coli, Enterococcus faecalis, and Listeria monocytogenes . Moreover, AgNPs adversely affected the morphology and ultrastructure of the Lasiodiplodia theobromae species complex, Neopestalotiopsis clavispora , and the Colletotrichum gloeosporioides species complex. These highlight the potential of these nanomaterials as bioactive agents to control postharvest microbial contamination and oxidative stress. However, further evaluation is still needed to fully realize the potential of these materials, particularly regarding their incorporation into food packaging systems, migration, release, cytotoxicity, and food-contact performance.