The successful green synthesis of zinc oxide nanoparticles was accomplished by using the leaf extract of Syzygium caryophyllatum (SC) as a stabilizing agent. The biosynthesized nanoparticles were characterized by UV-Vis spectroscopy, XRD, FE-SEM with EDS and FTIR analysis, confirming the structure, crystalline nature and elemental purity with predominant zinc and oxygen content. The nanoscale dimensions of particles ranging from 23.04 nm to 42.44 nm, with mean particle size 33.91 nm. The DPPH and ABTS radical scavenging activity demonstrated an IC50 of 47.3 µg/mL and 50.43 µg/mL suggesting its strong antioxidant capacity. The antibacterial study showed a dose-dependent inhibition in the growth of E. coli, B. subtilis, MSSA and P. aeruginosa with inhibition zones 24.7 ± 0.6 mm, 23.6 ± 0.8 mm, 27.2 ± 0.6 mm and 22.8 ± 0.3 mm respectively. Cytotoxicity tested on L929 mouse fibroblast cell line indicated high cell viability confirming good biocompatibility. The concentration of 80 to 100 µg/mL provided the favourable balance between strong bioactivity and acceptable biocompatibility in L929 cells. This eco-friendly biosynthesis highlights the multifunctional biological potential of S. caryophyllatum mediated zinc oxide nanoparticles for promising biomedical applications.
