Green Synthesis of Pithecellobium Dulce ‐Derived ZnO Nanoparticles as a Bioactive Mouthwash for Oral Health and Hygiene

ABSTRACT Zinc oxide nanoparticles (ZnO NPs) were phytogenically synthesized using Pithecellobium dulce leaves, and incorporated into mouthwash for oral care applications. Characterization of the ZnO NPs confirmed their successful synthesis, with UV–visible spectroscopy showing a peak at 349 nm, XRD revealing crystalline structure (average crystallite size ∼26.5 nm), and SEM/TEM indicating predominantly spherical morphology. Zeta potential (–14.4 mV) and DLS (155 nm) results demonstrated moderate colloidal stability, while EDX confirmed elemental purity. The formulated mouthwash was physically stable with no turbidity or sedimentation. Anti‐inflammatory activity, assessed by egg albumin and BSA denaturation assays, demonstrated dose‐dependent inhibition comparable to that of diclofenac sodium at higher concentrations. Antioxidant analysis, as determined by DPPH and hydrogen peroxide scavenging assays, revealed a strong free radical scavenging activity. Antibacterial studies demonstrated effective inhibition of Escherichia coli , Pseudomonas aeruginosa , and Staphylococcus aureus , particularly at higher nanoparticle concentrations. Artemia salina (brine shrimp) toxicity assay showed lower cytotoxicity of the ZnO NP‐based mouthwash (LC 50 = 78.8 µg/mL) compared to a commercial mouthwash (LC 50 = 59.39 µg/mL), indicating greater biosafety. These results support the application of fabricated ZnO NPs in mouthwash as a promising alternative to conventional oral care products, offering effective bioactivity with minimal toxicity and environmental impact.