Aqueous Punica granatum peel extract derived spray-dried silver nanoparticles with multifaceted bioactivity and its...

Aqueous extract from the peel of Punica granatum (P. granatum) was used to synthesis silver nanoparticles (Pg-AgNPs), and formulate the nanopowder by employing spray-drying process. Preliminary Pg-AgNPs production was validated by color transition from pale to deep brown as well as using an ultraviolet‒visible spectrophotometer. The optimized nanoparticle production was achieved at pH 8, Ag⁺ 500 mM, and 2 mL of aqueous P. granatum peel extract. Scanning electron microscopy (SEM) was used to validate the physical shape of the spray-dried nanopowder, revealing a spherical, ball-like structure with a uniform size of 1 µm. Transmission electron microscopy (TEM) exposed that the Pg-AgNPs were spherical and oval in form with sizes between 10 and 50 nm, and energy-dispersive X-ray spectroscopy (EDX) confirmed the existence of elemental silver. X-ray diffraction (XRD) revealed the crystalline phase of the Pg-AgNPs, and Fourier transform infrared spectroscopy (FT-IR) analysis implied the occurrence of bimolecular molecules that reduced Ag⁺ and capped the Pg-AgNPs. The antimicrobial activity against the cariogenic pathogens including bacteria Streptococcus mutans and the fungal strain Candida albicans exhibits potential activity. The DPPH assay indicated that the highest antioxidant activity (72%) occurred at 500 µg/mL Pg-AgNPs. A cytotoxicity study of P. granatum peel extract and Pg-AgNPs revealed an IC₅₀ value of 120 ± 1.42 and 82 ± 0.94 µg/mL, respectively. These findings confirm that the synthesized Pg-AgNPs have multiple characteristics and can be used for several applications.