An Evaluation of Antibacterial, Antioxidant, and Biocompatibility (Hemocompatibility) Nature of Green Synthesized ZnONPs: An In-vitro Approach

Introduction: Zinc oxide nanoparticles (ZnONPs) derived from plant extracts are garnering attention in medical applications due to their unique properties and eco-friendly synthesis, which enhance antimicrobial, antioxidant, anti-inflammatory, and anticancer effects. This research investigated the antibacterial and biocompatibility properties of previously characterized ZnONPs against bacterial pathogens, with biocompatibility evaluated through a hemocompatibility study using human blood samples. Methods: The bactericidal efficacy of phyto-synthesized ZnONPs was evaluated using the standard agar well-diffusion method against bacterial pathogens including E. coli, P. aeruginosa, S. aureus, K. pneumoniae, and S. flexneri. Moreover, their antioxidant capacity was evaluated using various nonenzymatic in-vitro assays, including ABTS, DPPH, TRP, and TAC assays. Results: The antibacterial efficacy of presynthesized and characterized ZnONPs showed dosage-dependent bactericidal activity against bacterial pathogens including Pseudomonas aeruginosa, Streptococcus pneumoniae, Staphylococcus aureus, Escherichia coli, and Klebsiella pneumoniae. At a concentration of 800 μg mL−1, the ZnONPs exhibited significant free radicals scavenging and reducing capabilities as demonstrated by DPPH, TAC, TRP, and ABTS assays. Moreover, the ZnONPs demonstrated excellent biocompatibility, as evidenced by hemocompatibility assay. Discussion: Phytochemicals derived from plants, including alkaloids, flavonoids, and tannins, stabilize nanoparticles, thereby enhancing their antibacterial effectiveness against Grampositive and Gram-negative bacteria. Green synthesized ZnONPs demonstrate reduced toxicity to human cells, notable antimicrobial effectiveness, strong antioxidant characteristics, and low cytotoxicity, making them beneficial for anti-aging therapies, wound healing, drug delivery, and tissue engineering. Conclusion: Green-synthesized ZnONPs demonstrate significant dose-dependent antibacterial efficacy against pathogenic bacteria such as P. aeruginosa, S. pneumoniae, S. aureus, E. coli, and K. pneumonia. The antioxidant test results demonstrated a significant dosedependent capacity of DPPH, TAC, TRP, and ABTS to eliminate free radicals. The antibacterial and antioxidant properties of ZnONPs exhibited notable biological compatibility.