Green and sustainable preparation of flower-like ZnO nanostructures via soft bio-template approach for the enhancement of biomedical applications

Investigation on the biomedical applications of flower-like Zinc Oxide (ZnO) nanostructures (NSs) synthesized by using aqueous extract of Oryza punctata (red rice) is reported for the first time. For the sustainable preparation of ZnO NSs, the precursors zinc nitrate and the rice extract act as the bio-template material. The optical energy bandgap value for the ZnO NSs was found to be 3.29 eV. The flower-like morphology of the ZnO NSs was confirmed by field emission scanning electron microscopy analysis. The ZnO NSs showed the potential cytotoxicity activity against MCF-7 cell line and antibacterial properties. Significant antioxidant activity was studied by the bio-prepared ZnO NSs against scavenging of DPPH (di(phenyl)-(2,4,6-trinitrophenyl) iminoazanium) free radicals. The flower-like ZnO NSs showed a significant anti-arthritic activity with a maximum inhibition of protein denaturation (78.94 ± 1.62%) and membrane protective activity (81.12 ± 1.25%) at a dose of 0.5 mg/mL concentration.