Green Synthesis of Fucoidan‐Doped Zinc Oxide Nanoparticles Using Gymnema sylvestre Leaf Extract and Evaluation of Their Antibacterial, Antioxidant, and Anti‐Inflammatory Activities

ABSTRACT

The development of sustainable and environmentally friendly nanoparticle‐based techniques has gained more attention in recent years, especially for biomedical applications. In this research, Zinc oxide nanoparticles doped with fucoidan (ZnONPs/Fu) are biosynthesized using leaf extract from Gymnema sylvestre ( G. sylvestre ) as a natural stabilizing and reducing agent. UV–vis spectroscopy was utilized to characterize the synthesized ZnONPs/Fu revealing absorption peaks around 369 and 580 nm, corresponding to zinc and fucoidan, respectively. Fourier‐transform infrared (FTIR) spectroscopy identified distinct functional groups with peaks observed at 1025, 1404, 1609, 2917, and 3339 cm ^{− 1} , corresponding to C─O, C═C, C═O, CH (alkanes), and N─H stretching vibrations. Scanning electron microscopy (SEM) and x‐ray diffraction (XRD) analyses confirmed the nanoparticles’ nanoscale size and crystalline wurtzite structure. ZnONPs/Fu exhibited strong antibacterial activity against multidrug‐resistant bacterial strains, including Enterococcus faecalis, Pseudomonas aeruginosa , methicillin‐resistant Staphylococcus aureus (MRSA), and Klebsiella pneumoniae , as evidenced by notable inhibition zones at a concentration of 80 µg/mL. The in vitro antioxidant activity reached 86% at 100 µg/mL, compared to 92.6% for the ascorbic acid control. The highest anti‐inflammatory activity was 60.9% at 100 µg/mL, while the standard drug diclofenac had 64.4%. Future studies should focus on elucidating the molecular mechanisms of action, optimizing synthesis parameters, validating in vivo safety and efficacy, and exploring potential applications in drug delivery, wound healing, and therapeutic interventions.