The development of sustainable nanomaterials through green synthesis has gained significant attention as an alternative to conventional chemical methods that contribute to environmental pollution. In the present study, zinc oxide nanoparticles (ZnO-NPs) were successfully synthesized using aqueous flower extract of Ixora coccinea as a natural reducing and stabilizing agent. The phytochemical constituents such as flavonoids and phenolic compounds facilitated the bioreduction of zinc ions, leading to the formation of stable nanoparticles.

The formation of ZnO-NPs was confirmed by UV–Visible spectroscopy, which exhibited a characteristic absorption peak at ~372 nm. Fourier-transform infrared spectroscopy (FTIR) analysis revealed the presence of functional groups responsible for capping and stabilization of nanoparticles. X-ray diffraction (XRD) studies indicated a crystalline hexagonal wurtzite structure with an average particle size of 28–35 nm, calculated using the Debye–Scherrer equation. Scanning electron microscopy (SEM) images demonstrated predominantly spherical morphology with slight agglomeration.

The biosynthesized ZnO-NPs exhibited significant antioxidant activity with ~68% DPPH radical scavenging activity at higher concentrations. Additionally, antimicrobial studies showed notable inhibition zones against Escherichia coli (~14 mm) and Staphylococcus aureus (~16 mm), indicating strong antibacterial potential. The enhanced biological activity is attributed to the synergistic effect of ZnO and bioactive phytoconstituents from Ixora coccinea.

The eco-friendly synthesis route not only reduces the use of toxic chemicals but also supports sustainable material development aligned with environmental protection and decarbonization strategies. The findings suggest that Ixora coccinea-mediated ZnO nanoparticles hold promising potential for applications in biomedical and environmental domains, including antimicrobial formulations and pollutant remediation.