Phytogenic copper and zinc nanoparticles from Ephedra foeminea: Characterization and evaluation of antimicrobial, antioxidant, and cytotoxic activities

The green synthesis of copper nanoparticles (CuNPs) and zinc nanoparticles (ZnNPs) using Ephedra foeminea extract demonstrated promising potential for biomedical applications. The CuNPs and ZnNPs were synthesized by reacting 20 mL of aqueous Ephedra foeminea extract with 80 mL of 5 mM copper sulfate or zinc acetate solution at pH 7–8 and 37 °C for 24 h under gentle magnetic stirring. The synthesized nanoparticles were characterized using UV–Vis spectroscopy, FTIR, EDX, XRD and SEM analyses. UV–Vis spectroscopy revealed characteristic absorption peaks at 580 nm for CuNPs and 350 nm for ZnNPs, confirming nanoparticle formation. FTIR analysis identified the functional groups, while EDX analysis confirmed the elemental composition and purity of the synthesized CuNPs and ZnNPs. XRD analysis confirmed the crystalline nature of the synthesized nanoparticles, while SEM analysis showed the morphology and average particle sizes of approximately 20 nm for CuNPs and 35 nm for ZnNPs. The antibacterial activity of the synthesized nanoparticles was evaluated against both Gram-positive and Gram-negative pathogenic bacterial strains. The nanoparticles exhibited significant antibacterial activity, with inhibition zones ranging from 15 to 31 mm for CuNPs and 10 to 25 mm for ZnNPs. Furthermore, the DPPH assay demonstrated a dose-dependent increase in free radical scavenging activity for CuNPs, ZnNPs, and ascorbic acid. The ZnNPs exhibited higher antioxidant activity than CuNPs, with an IC₅₀ of 45 µg/mL, followed by CuNPs with an IC₅₀ of 59 µg/mL, while ascorbic acid showed the highest antioxidant activity with an IC₅₀ of 28 µg/mL. In addition, the anticancer potential of the nanoparticles, crude extract and the positive control doxorubicin was evaluated against the HepG2 human liver cancer cell line using the MTT assay. All test samples exhibited dose-dependent cytotoxic activity. The ZnNPs showed greater cytotoxic activity with an IC₅₀ of 45 µg/mL, followed by CuNPs with 55 µg/mL and the crude extract with 60 µg/mL, whereas doxorubicin demonstrated the highest cytotoxic potency with an IC₅₀ of 5.54 µg/mL. Additionally, preliminary phytochemical screening of Ephedra foeminea extract revealed the presence of bioactive compounds, including flavonoids, alkaloids, saponins, phenols and tannins, which contribute to the reduction, stabilization, and biological activities of the synthesized nanoparticles. Overall, the green synthesis of CuNPs and ZnNPs using Ephedra foeminea extract provides an eco-friendly and sustainable approach for producing biologically active nanoparticles with notable antibacterial, antioxidant, and anticancer properties.