A recent study published in Bioinorganic Chemistry and Applications reported a green synthesis method for silver nanoparticles (AgNPs) using peel extract from the “Mollar de Elche” variety of pomegranate.
The work demonstrates how natural plant extracts can serve as both reducing and stabilizing agents in nanoparticle formation, offering a sustainable alternative to traditional chemical synthesis routes.
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Background
The study contributes to a growing interest in biogenic, or green, synthesis of metal nanoparticles—particularly silver—due to their antibacterial, antioxidant, and antitumor properties. Pomegranate (Punica granatum), known for its high content of phenolic compounds such as punicalagin, offers a rich source of bioactive molecules that can drive nanoparticle synthesis while also imparting therapeutic properties.
The researchers used pomegranate peel extract specifically for its high concentration of phenolics, which can both reduce silver ions and stabilize the resulting nanoparticles. This approach addresses the need for environmentally friendly synthesis methods that reduce the use of hazardous reagents. To optimize the process, the team applied a Box–Behnken design (BBD), a statistical method used in response surface methodology (RSM) for evaluating interactions between multiple synthesis parameters.
The Current Study
Silver nanoparticles were synthesized by mixing varying concentrations of silver nitrate with pomegranate peel extract. The peel extract was obtained via a simple extraction method, and three key parameters were tested using the BBD approach: silver nitrate concentration, extract concentration, and reaction temperature.
The resulting nanoparticles were characterized using several techniques. Ultraviolet-visible (UV-Vis) spectroscopy was used to confirm the formation of nanoparticles via surface plasmon resonance. Fourier-transform infrared spectroscopy (FTIR) identified functional groups involved in stabilization.
X-ray diffraction (XRD) provided information on crystallinity, and field emission scanning electron microscopy (FESEM) was used to study particle size and morphology. Hydrodynamic diameter, polydispersity index (PDI), and zeta potential were also measured to assess dispersion and colloidal stability.
To evaluate antibacterial efficacy, the synthesized AgNPs were tested against Escherichia coli and Staphylococcus aureus using standard antimicrobial assays. The researchers also embedded the nanoparticles in nanofibrous scaffolds to assess the potential for biomedical applications such as wound dressings.
Results and Discussion
The BBD model effectively optimized the synthesis process, yielding silver nanoparticles with controlled size and good dispersion. The AgNPs were predominantly spherical and exhibited uniform morphology.
UV-Vis spectra confirmed successful formation, with a clear surface plasmon resonance peak. FTIR analysis revealed that functional groups from the pomegranate extract were involved in reducing and capping the nanoparticles, helping to stabilize the colloid.
Antibacterial assays showed that the AgNPs exhibited significantly enhanced antimicrobial activity against both Escherichia coli and Staphylococcus aureus compared to conventional antimicrobial agents. This activity was retained even after incorporating the nanoparticles into nanofibrous scaffolds, highlighting their potential for biomedical applications such as wound dressings.
The study underscored the importance of controlled synthesis conditions. The interaction between phenolic compounds in the pomegranate extract and silver ions was key in forming stable, bioactive nanoparticles. These bio-reduced nanoparticles benefited from the dual function of the extract—acting both as a reducing agent and a stabilizer—leading to particles with consistent antibacterial performance.
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Conclusion
This study demonstrates a green synthesis route for silver nanoparticles using pomegranate peel extract as a natural reducing and stabilizing agent. Optimization through the Box–Behnken design led to consistent nanoparticle formation and enhanced antibacterial activity. The AgNPs showed strong performance against common bacterial strains and retained efficacy when incorporated into nanofiber scaffolds.
Beyond their immediate biomedical potential, these results contribute to sustainable nanomaterial synthesis by showcasing the value of plant-derived compounds in reducing reliance on synthetic chemicals. The use of pomegranate waste not only supports environmental goals but also offers a cost-effective strategy for producing functional nanomaterials.
Journal Reference
Díaz-Puertas R., et al. (2025). An innovative approach based on the green synthesis of silver nanoparticles using pomegranate peel extract for antibacterial purposes. Bioinorganic Chemistry and Applications. DOI: 10.1155/bca/2009069, https://onlinelibrary.wiley.com/doi/10.1155/bca/2009069