Photocatalytic degradation of organic dyes and biological potentials of biogenic zinc oxide nanoparticles synthesized using the polar extract of Cyperus scariosus R.Br. (Cyperaceae)

In this study, the polar root extract of Cyperus scariosus R.Br. was used for the biogenic synthesis of ZnO NPs. The results of this study show that ZnO NPs have a spherical structure with an average size of 85.4 nm. The synthesized catalysts were tested for their photocatalytic activity by degrading methyl orange and methylene blue under sunlight. Improved degradation efficiencies of 79.44% and 84.92% were achieved within 120 min. ZnO NPs exhibited strong antibacterial activity against both Gram-positive Listeria monocytogenes (18 mm) and Staphylococcus epidermidis (20 mm) and Gram-negative strains of Escherichia coli (16 mm) and Bordetella bronchiseptica (14 mm), as shown by the inhibition zones, which were comparable to the positive control (ceftriaxone) but larger than the plant root extract. ZnO NPs showed high antioxidant activity, as a ferric-reducing antioxidant power assay value of 66.29 µg (AAE µg·mL−1) and a DPPH value of 57.44 µg (AAE µg·mL−1) were obtained at a concentration of 500 µL, which was higher than those of the C. scariosus root extract. Quantification of the total phenolic and flavonoid content yielded values of 57.63 µg (GAE µg·mL−1) and 70.59 µg (QCE µg·mL−1), respectively. At a concentration of 500 μL (1 mg·mL−1), the tested nanoparticles (NPs) showed a greater anti-inflammatory effect (84.12%) compared to the root extract of C. scariosus (34.39%). Overall, our findings highlight the versatile properties of green synthesized ZnO NPs and demonstrate their potential for environmental remediation and antimicrobial formulations, as well as promising candidates for further investigation in biomedical fields such as drug delivery and therapy.