Synthesis and Characterization of Parquetina nigrescens Plant-Mediated Zinc Oxide Nanoparticles and Evaluation of Their Antioxidant, Antifungal, and Antimicrobial Activity

In the present work, zinc oxide nanoparticles (ZnO NPs) were biosynthesized using ethanolic leaf extract of Parquetina nigrescens, which acted as both reducing and stabilizing agents. The obtained nanoparticles were characterized using ultraviolet–visible (UV–Vis) spectroscopy, Fourier-transform infrared (FTIR) spectroscopy, X-ray diffraction (XRD), scanning electron microscopy (SEM), and thermogravimetric–differential thermal analysis (TGA–DTA). Phytochemical screening of the extract revealed the presence of alkaloids, flavonoids, saponins, tannins, and phenolic compounds. The UV–Vis spectrum showed a characteristic absorption peak at ۴۱۴ nm, confirming nanoparticle formation, while FTIR analysis highlighted the involvement of phytochemicals in surface functionalization. XRD patterns confirmed a hexagonal wurtzite crystalline structure with an average crystallite size of ۱۵.۶ nm. SEM micrographs displayed porous, irregularly shaped, agglomerated nanoscale flakes. Thermal analysis indicated good stability, with sequential weight losses attributed to moisture evaporation and decomposition of residual organics. Antioxidant evaluation through the DPPH assay demonstrated strong radical scavenging activity (IC₅₀ = ۳۴.۸۵ µg/mL). Antifungal tests revealed that ZnO NPs exhibited greater inhibitory effects than the crude extract, particularly against Candida ethanolica compared to Saccharomyces cerevisiae. Antibacterial assays showed pronounced activity against Staphylococcus aureus (ATCC ۳۳۸۶۳) and Bacillus subtilis (ATCC ۲۳۸۵۷), whereas Salmonella typhi (ATCC ۱۹۴۳۰) and Pseudomonas aeruginosa (ATCC ۲۷۸۵۳) were less susceptible. Collectively, these results indicate that Parquetina nigrescens-mediated ZnO NPs possess strong antioxidant, antibacterial, and antifungal properties, highlighting their promise as sustainable alternatives in biomedical and pharmaceutical applications.

کلیدواژه ها:

Green synthesis ، ZnO NPs ، Characterization ، Antioxidant ، Antibacterial ، Antifungal