Assessing the Antibacterial and Antioxidant Potentials of Nickel Nanoparticles Fabricated via C. Procera Leaf Extraction

The green synthesis of nanoparticles using plant-based biomolecules provides an eco-friendly and sustainable alternative to conventional chemical methods, while also addressing pressing global concerns such as antimicrobial resistance and oxidative stress–related diseases. In this study, nickel nanoparticles (NiNPs) were synthesized using aqueous leaf extract of Calotropis procera, and their physicochemical properties, antibacterial potential, and antioxidant activities were evaluated. UV–Vis spectroscopy confirmed nanoparticle formation with a red-shifted absorption band at ~360 nm compared to the leaf extract control (276 nm). FTIR spectra revealed hydroxyl, carbonyl, and phenolic groups as key reducing and stabilizing agents, while XRD analysis indicated a structural transition from semi-crystalline plant constituents to highly crystalline nickel-based nanostructures. Antibacterial assays against six clinically relevant pathogens (Staphylococcus aureus, Escherichia coli, Klebsiella pneumoniae, Pseudomonas aeruginosa, Salmonella typhi, and Clostridium spp.) demonstrated dose-dependent inhibition, with NiNPs consistently outperforming the crude extract. Minimum inhibitory and bactericidal concentration values for NiNPs (12.5 and 25 mg/mL, respectively) confirmed broad-spectrum bactericidal activity. Antioxidant analysis using the DPPH assay further showed that NiNPs exhibited strong radical scavenging capacity (IC₅₀ = 3.78 mg/mL), surpassing the crude extract (IC₅₀ = 8.81 mg/mL). These results highlight the synergistic effects of phytochemicals and nanoscale nickel, yielding enhanced antibacterial and antioxidant properties. Overall, C. procera-mediated NiNPs represent promising eco-friendly nanomaterials with potential applications in biomedical, pharmaceutical, and environmental fields. Future studies should focus on in vivo validation, toxicity profiling, and synergistic interactions with conventional therapeutics.