Exploring Biomedical Potential of Phytochemical Synthesized Iron Nanoparticles: <i>In Vivo</i> and <i>In Vitro</i> Evaluation

Nanobiotechnology has garnered immense attention across multidisciplinary fields, particularly for its biopharmaceutical applications. This study aims to synthesize iron nanoparticles (FeNPs) using an aqueous extract of <i>Murraya koenigii</i> (AE-Mk) and evaluate their biological activity. The initial synthesis was confirmed via ultraviolet–visible spectroscopy, which displayed an absorption band with a maximum wavelength at 620 nm. The contribution of AE-Mk to FeNPs synthesis was assessed using Fourier transform infrared spectroscopy, which identified various functional groups, including alcohol, N–H stretch, aliphatic primary amine, carboxylic acid, alkyne, and alkane/alkene. Characterization confirmed the elemental nature, amorphous form, and aggregate morphology of FeNPs, as observed through energy-dispersive X-ray, X-ray diffraction, and scanning electron microscopy, respectively. FeNPs exhibited a total phenolic content of 84.23 μg GAE/mg and a total flavonoid content of 78.62 μg QE/mg at 1 000 μg/mL. Additionally, they showed significant reducing ability (69.43%) and prominent scavenging potential against 2,2-diphenyl-1-picrylhydrazyl (80.63%), nitric oxide (73.01%), and hydrogen peroxide (71.62%) at 600 μg/mL. Strong antimicrobial activity was observed at 500 μg/mL against <i>Bacillus subtilis</i> (19 mm), <i>Escherichia coli</i> (16 mm), <i>Schizophyllum commune</i> (19 mm), and <i>Aspergillus niger</i> (13 mm). The biological compatibility of FeNPs was evaluated in Wistar rats, showing no adverse effects at the administered dose (50 μg/mL). Furthermore, <i>in vitro</i> anticancer activity at 100 μL showed significant cell viability loss (58.23%, IC₅₀: 51.35) against HeLa cell lines. These findings highlight the dynamic potential of FeNPs for biomedical applications.