Comparative physicochemical and biomedical evaluation of silver nanoparticles synthesized using seed and pod extracts of Amomum aromaticum

The green synthesis of metal nanoparticles has emerged as a sustainable and biocompatible approach for biomedical applications. In this study, silver nanoparticles (AgNPs) were synthesized using seed and pod extracts of Amomum aromaticum (Bengal cardamom) , and their physicochemical and biological properties were systematically compared. The aqueous extracts served as both reducing and stabilizing agents under near-neutral conditions (pH 6.0 ± 0.2), optimizing nanoparticle formation and stability [41–45]. UV–Visible spectroscopy confirmed the characteristic surface plasmon resonance peaks at 432 nm for seed-derived AgNPs (Seed-AgNPs) and 445 nm for pod-derived AgNPs (Pod-AgNPs), indicating size differences. FTIR analysis revealed involvement of flavonoids, phenolic acids, and tannins in reduction and capping, with seed extracts exhibiting stronger flavonoid-associated peaks and pod extracts displaying dominant phenolic/tannin signals [26,27,37]. X-ray diffraction and TEM confirmed crystalline nature, with Seed-AgNPs being smaller (15–20 nm) and more spherical, while Pod-AgNPs were larger (25–30 nm) and semi-spherical [36,37]. Zeta potential analysis indicated higher colloidal stability for Seed-AgNPs (−25.4 mV) compared to Pod-AgNPs (−18.1 mV) [38].Biological evaluations demonstrated functional divergence: Seed-AgNPs exhibited superior antibacterial activity against S. aureus and E. coli , attributed to their smaller size and higher surface area [38–40], whereas Pod-AgNPs showed enhanced antioxidant potential (~81% DPPH scavenging) and wound-healing efficiency (~78% closure in 24 h), linked to phenolic and tannin capping [41–42]. Cytotoxicity assays confirmed biocompatibility of both nanoparticles, with Seed-AgNPs exhibiting slightly higher effects at elevated concentrations [43]. Mechanistic insights suggest flavonoid-rich seeds promote rapid nucleation and stabilization, while phenolic-rich pods favor slower growth with antioxidant functionality, demonstrating organ-specific phytochemical-driven tunability in nanoparticle synthesis [44,45]. This study highlights the strategic use of plant organ extracts to tailor AgNP properties for targeted biomedical applications, providing a framework for precision-guided green nanotechnology.