Green Synthesis of ZnO Nanoparticles Using Plantago lanceolata Leaf Extract: Enhanced Antibacterial Activity, Biocompatibility, and Comparative Evaluation with Chemically Synthesized Counterparts

Metal oxide nanoparticle green manufacturing is a sustainable way of producing biocompatible nanomaterials with increased biological activity. To produce zinc oxide nanoparticles (ZnO NPs, ZR), Plantago lanceolata (Ribwort Plantain) leaf extract was employed as a natural reducing and stabilizing agent. These biosynthesized nanoparticles were compared to chemically made ZnO NPs (ZC) to see how plant-derived surface functionalization influenced physicochemical properties, antibacterial activity, antioxidant potential, and cytotoxicity. UV-Vis, FTIR, XRD, SEM, EDS, and particle size measurements revealed crystalline ZnO NPs with an average diameter of ~26 nm and effective phytochemical capping. ZR2 nanoparticles demonstrated superior antibacterial efficacy against Staphylococcus aureus and Pseudomonas aeruginosa, with low MICs (62.5-125 µg/mL) and bactericidal characteristics. They showed antifungal efficacy against Candida albicans and high biocompatibility, causing ≤3% hemolysis in human red blood cells. DPPH tests indicated moderate antioxidant activity, implying a functional shift in phytochemicals towards nanoparticle stability. In general, Ribwort Plantain-mediated ZnO NPs exhibit significant antibacterial activities, moderate antioxidant activity, and minimal cytotoxicity, making them promising candidates for pharmacological, medicinal, and agricultural applications.