GREEN SYNTHESIS OF ZINC OXIDE NANOPARTICLES USING OKRA FRUIT EXTRACT: PHYSICOCHEMICAL CHARACTERIZATION AND EVALUATION OF WOUND HEALING, ANTIOXIDANT, AND CYTOTOXIC ACTIVITIES

Abstract

Cancer is a leading cause of global mortality, which points to the need for alternative therapies due to the limitations of current chemotherapy, such as low efficacy, toxicity, and drug resistance. Nanotechnology, especially the green synthesis of metal and semiconductor nanoparticles, offers a promising solution with advantages in cost-effectiveness, environmental sustainability, and reduced toxicity. This study investigates the synthesis of zinc oxide nanoparticles (ZnO NPs) via bioreduction of Zn²⁺ ions using okra fruit extract (OFE) under rapid, cost-effective, and environmentally benign conditions. OFE-ZnO nanoparticles were characterized by UV-Vis spectroscopy, FTIR, SEM, EDX, XRD, DLS, and zeta potential techniques. UV-Vis analysis for OFE-ZnO nanoparticles showed a surface plasmon resonance peak at 374 nm. In FTIR analysis, a distinct Zn-O stretching vibration was obtained at 618 cm⁻¹. SEM images revealed that the nanoparticles were spherical in structure with a homogeneous distribution, while EDX analysis confirmed the presence of zinc. XRD patterns showed high crystallinity and purity, while DLS analysis revealed an average particle size of 141.7 nm, and the zeta potential of these nanoparticles was calculated as -7.42 mV. Antioxidant activity was evaluated using DPPH and ABTS tests, and it was revealed that OFE-ZnO nanoparticles had significant activity at doses of 123.04±2.37 μg/mL and 56.34±1.84 μg/mL, respectively. The MTT assay showed that cytotoxicity resulted in a significant decrease in cell viability in A549 (lung cancer cell line), MDA-MB-231 (breast cancer cell line), SH-SY5Y (neuroblastoma cell line), and L929 (mouse fibroblast cell line) treated with 1000 µg/mL OFE-ZnO nanoparticles, with viability rates ranging from 11.40±4.12% to 16.30±5.66%. Furthermore, wound healing assays revealed better grafting in A549 cells treated with OFE-ZnO nanoparticles compared to cells treated with OFE alone (25.97±3.77%). The findings demonstrate that OFE-ZnO nanoparticles possess significant antioxidant, cytotoxic, and wound-healing properties and have potential as environmentally sustainable nanomaterials for biomedical use.