Green Synthesis, Physicochemical Characterization, and Antioxidant Evaluation of Silver Nanoparticles Derived from Clerodendrum infortunatum

This study reports the green synthesis, physicochemical characterization, and biological evaluation of silver nanoparticles (AgNPs) prepared using Clerodendrum infortunatum. The plant material was extracted by macerating 100 g of powdered leaves in 500 mL of 95% ethanol for 72 h, yielding a crude extract stored at –20 °C for further use. For nanoparticle synthesis, 10 g of leaf powder was boiled in 100 mL of water at 60 °C for 20 min, and 10 mL of this filtrate was reacted with 90 mL of 1 mM AgNO₃ (0.017 g/100 mL) under stirring (600 rpm) for 2–4 h, producing a characteristic dark-brown dispersion. UV–Vis analysis showed a strong surface plasmon resonance band at 293.03 nm with optical density >3.3, indicating efficient Ag⁺ reduction and good dispersion. FT-IR bands at 3980–3865 cm⁻¹ (O–H/N–H), 971 cm⁻¹ (C–O/C–N), 686–602 cm⁻¹, and metal–oxygen vibrations at 547–440 cm⁻¹ confirmed phytochemical capping and Ag–O bonding. DLS revealed a Z-average size of 89.59 nm with PDI 0.455; the dominant population at 127.2 nm (85.9%) indicated nanoscale predominance with minor aggregates at 4478 nm (7.1%). EDAX verified elemental silver (~3 keV), while FE-SEM and HR-TEM showed nanoscale morphology. Biologically, CI-Ag-NPs exhibited enhanced DPPH scavenging, reaching ~90% inhibition at 120 μg/mL, outperforming the crude extract (~70%) and approaching ascorbic acid (>80% at lower doses). The phytochemical-capped CI-Ag-NPs demonstrate robust stability, nanoscale uniformity, and superior antioxidant and supporting their potential in biomedical applications