Green Synthesis, Characterization, and Biological Evaluation of Zinc Oxide Nanoparticles Using Plant Extracts

Abstract

The use of green technology has become popular in nanomaterial synthesis to produce biologically active nanomaterials in an environment friendly way. In the present investigation, zinc oxide nanoparticles (ZnO-NPs) were produced using an aqueous leaf extract of *Moringa oleifera* as a reducing and stabilizing agent. The characterization of ZnO-NPs was analysis using UV–Visible spectrophotometry, FTIR, XRD, EDX, and SEM techniques. The peaks of the UV–Visible analysis indicated the appearance of characteristic absorption at 368 nm wavelength, and FTIR analysis showed the role of phytochemicals from plants in the formation of nanoparticles. The XRD results suggested that ZnO-NPs were crystalline in nature with an average size of around 22 nm. While SEM indicated spherical shape of the nanoparticles, EDX analysis confirmed zinc and oxygen as the main constituent elements. Moreover, the ZnO-NPs were found to possess antimicrobial activity against *E. coli, S. aureus*, and *P. aeruginosa*. The maximum bactericidal effect of ZnO-NPs was observed on *S. aureus*. The MIC values were 100 and 150 µg/mL. In addition, the prepared ZnO-NPs showed concentration-dependent antioxidant property and significant antibiofilm activities. The biological activities of the nanoparticles could be attributed to the synergic activity of phytochemical compounds from the plant material and the nanoparticle properties of ZnO. In summary, the results indicated that M. oleifera-assisted ZnO-NPs are good antimicrobial and antioxidant candidates.