Extraction, Phytochemical Screening, Green Synthesis of Silver Nanoparticles (Ag-NPs), and Antioxidant Potential of Aphanamixis polystachya.

This study reports the green synthesis of silver nanoparticles (Ag-NPs) using an
aqueous leaf extract of Aphanamixis polystachya, a plant known for its medicinal
properties. The biosynthesized Ag-NPs were characterized using UV-Vis spectroscopy,
FTIR, SEM, XRD, DLS, and zeta potential analysis. The UV-Vis spectrum displayed a
surface plasmon resonance peak at 425 nm, and particle size analysis showed an
optimized average diameter of 39.7 nm. Zeta potential was recorded at -9.29 mV,
confirming colloidal stability, while entrapment efficiency reached 82.2%. Functional
groups such as O–H, C=O, and C–N identified by FTIR analysis facilitated nanoparticle
formation and stabilization. SEM revealed spherical morphology and XRD confirmed a
crystalline face-centered cubic structure with peaks at 38.1°, 44.3°, 64.4°, and 77.4°. In
vitro antioxidant evaluation using DPPH assay demonstrated superior activity of Ag-NPs
(IC50 = 0.68 ± 0.06 mg/mL) over the crude leaf extract (IC50 = 1.57 ± 0.07 mg/mL).
Additionally, the Ag-NPs exhibited a drug release of 98.27 ± 2.76% over 12 hours and
remained physically stable over three months. These findings imply that the leaf extract
of A. polystachya functions as a sustainable, eco-friendly, and efficient reducing and
capping agent for the production of stable Ag-NPs, with encouraging prospects for
additional biological and medicinal uses.