Preparation of Zinc Oxide Nanoparticles Assisted by Okra Mucilage and Evaluation of its Biological Activities

Background: In this study, zinc oxide nanoparticles (ZnO-NPs) were biologically synthesized from Abelmoschus esculentus L. (Okra) mucilage fraction (OM). Methods: Analytical techniques were employed to study the formation and properties of OM-ZnO NPs, including their morphology, shape, size distribution, and surface charges. Additionally, OM-ZnO NPs were assessed for their antimicrobial, antioxidant, and cytotoxic properties. Results: UV-visible spectroscopy confirmed the formation of OM-ZnO NPs, evident by the appearance of an SPR peak at 368.8 nm. The FTIR spectroscopy demonstrated that OM functional groups contribute to the formation and stability of the NPs. Micrographs from TEM and SEM showed that OM-ZnO NPs ranged from 15-40 nm in diameter, whereas hydrodynamic diameter and surface charge values obtained from Zeta and DLS were 72.8 nm and 14.6 mv, respectively. XRD analysis indicated the OM-ZnO NPs were crystalline with a wurtzite structure and a crystallite size of 27.3 nm, while EDX revealed a zinc: oxygen ratio of 67.5:34. Further, the OM-ZnO NPs demonstrated significant antimicrobial activity in response to different types of bacteria. In the antioxidant assay, the OM-ZnO NPs scavenged DPPH with 68.6% of the efficiency of ascorbic acid (100%). Conclusion: The present study demonstrated the cytotoxic efficacy of MO-ZnO NPs against MCF7 cells with an IC50 of 43.99 μg/ml. Overall, the green synthesis of ZnO NPs by OM was successful for many biological applications, such as antimicrobial, antioxidant, and anticancer. Moreover, OM-ZnO NPs can be applied as a biologically-derived nanotherapeutic agent.