Ni-Fe Nanoparticles from Eugenia jambolana Extract Show Enhanced Anti-Biofilm, Anti-Inflammatory, and Antioxidant Effects

Introduction: Metallic nanoparticles are of interest for their potent bactericidal and anti-biofilm effects within a favorable therapeutic index. This study reports the green synthesis of bimetallic nickel-iron (Ni-Fe) nanoparticles using Eugenia jambolana extract and evaluates their antimicrobial, anti-biofilm, antiinflammatory, and antioxidant activities. Methods: Ni-Fe nanoparticles were synthesized using E. jambolana extract and characterized for crystalline structure, size, stability, zeta potential, and functional groups. Antimicrobial activity was tested against Grampositive (Bacillus subtilis, Staphylococcus aureus), Gram-negative (Escherichia coli, Pseudomonas aeruginosa), and Candida albicans. Anti-biofilm potential was assessed via inhibition and dispersion assays, EPS quantification, and in situ visualization. Anti-inflammatory activity was measured through protein denaturation and nitric oxide scavenging assays, while antioxidant capacity was determined using DPPH and H2O2 scavenging tests. Results: Crystalline, stable Ni-Fe nanoparticles with favorable functional groups were obtained. At 200 μg/mL, they showed broad-spectrum antimicrobial activity. Biofilm formation was reduced by 50% at 250 μg/mL, and dispersion occurred at 10-50 μg/mL, with S. aureus most susceptible. EPS inhibition at 50 μg/mL was 78% (E. coli), 70% (P. aeruginosa), 73% (B. subtilis), and 91% (S. aureus). Visualization confirmed strong adherence to biofilms. At 250 μg/mL, protein denaturation inhibition reached 45%, nitric oxide scavenging 42.6%, DPPH scavenging 44%, and H2O2 scavenging 49%. Discussion: Ni-Fe nanoparticles exhibit strong antimicrobial, anti-biofilm, anti-inflammatory, and antioxidant activities, notably against S. aureus. High EPS inhibition and biofilm dispersion suggest potential against biofilm- associated, drug-resistant infections. result: Ni-Fe NPs exhibited broad-spectrum antimicrobial activity, effectively inhibiting Gram-positive (B. subtilis, S. aureus), Gram-negative (E. coli, P. aeruginosa), and fungal (C. albicans) strains at 200 µg/mL. Biofilm formation was reduced by 50% at 250 µg/mL, while biofilm dispersion occurred at concentrations of 10–50 µg/mL, with the highest efficacy against S. aureus. EPS quantification showed inhibition rates of 78% (E. coli), 70% (P. aeruginosa), 73% (B. subtilis), and 91% (S. aureus) at 50 µg/mL. In situ visualization confirmed Ni-Fe NPs adhered to bacterial biofilms. Anti-inflammatory assays demonstrated 45% inhibition of protein denaturation and 42.6% NO scavenging at 250 µg/mL. Antioxidant assessments revealed 44% DPPH radical scavenging and 49% H₂O₂ scavenging. Conclusion: Green-synthesized Ni-Fe nanoparticles from E. jambolana show multifunctional bioactivities, offering promise for therapeutic applications targeting resistant and biofilm-related infections.