The biosynthesis of copper oxide (GS-CuO) nanoparticles utilizing Magnolia champaca floral extract was studied, where the Magnolia champaca was used for the reduction of precurosor to elemental CuO nanopartciles which also provides stabilization. Physiochemical properties of GS-CuO nanoparticles were described utilizing analytical strategies like UV-Vis, XRD, FT-IR, SEM, TEM, Zeta potential and DLS analysis. The UV-Visible spectrum gave maximum absorbance in the scale of 250-350 nm. The biosynthesized GS-CuO was crystallite in nature and it was investigated by XRD and was verified with JCPDS NO: 89-589. FT-IR analysis spectrum at 3302 cm-1 is assigned for alcoholic hydroxide group, 1022 cm-1 correspondings to CH3 shaking vibration respectively. The morphology of biosynthesized nanoparticles was between 20 to 40 nm and spherical shape was investigated utilizing TEM. The antoxidant potentiality of GS-CuO was evaluated by DPPH, ABST test, that demonstrated inhibition values at 76.30% and 66.46% respectively. Toxicity quality examination was performed utilizing morphological investigation, incubating, and viability rate examination on zebrafish embryonic model. The toxicity quality assessment with zebrafish uncovered organ advancement with various viability and hatching speed at 48 and 72 hpf with LC50 of 500 ± 15 mg/L.