Phytofabrication of Zinc Oxide Nanoparticles Using Sida cordifolia L. and Their Biomedical Applications

Eco-friendly approaches for nanoparticle synthesis have gained attention due to their sustainability and reduced environmental impact. Zinc oxide nanoparticles (ZnO NPs) exhibit versatile bioactivities, but conventional synthesis methods often involve toxic reagents. ZnO NPs were synthesized through a one-step bioreduction process, utilizing the crude leaf extract of Sida cordifolia L. and employing the combustion method at 400°C. Characterization of the nanoparticles was analyzed through UV–Vis spectroscopy, FTIR, XRD, DLS, and SEM to assess structural and morphological properties. Antibacterial efficacy was tested through the resazurin plate assay, and antioxidant activity was evaluated through the hydrogen peroxide scavenging assay. UV–Vis shows a characteristic peak at ∼370 nm, which corresponds to the fundamental band gap transition of ZnO. FTIR and DLS verified organic moiety incorporation and nanoparticle size, respectively, while XRD confirmed the wurtzite structure. The average diameter of synthesized nanoparticles was between 88.5 and 90.2 nm. SEM provides detailed insights into their size, shape, surface morphology, and structural features. Functionalized nanoparticles demonstrated enhanced antibacterial efficacy against E. coli, K. pneumoniae, S. aureus, and E. faecalis with MICs of 12.5 μg/mL for Gram-positive bacteria (S. aureus and E. faecalis), 100 μg/mL for E. coli, and 12.5 μg/mL for K. pneumoniae. Antioxidant activity shows concentration-dependent radical scavenging. At a concentration of 3.12 μg/mL, ZnO NPs exhibited 28.7 ± 1.2% scavenging activity, which progressively increased to 64.3 ± 2.5% at 100 μg/mL. This one-pot green synthesis provides a simple, scalable approach to biofunctionalized ZnO NPs with potent antibacterial and antioxidant properties, offering potential for biomedical applications.