Synthesis of nanoparticles employing plant extracts represents a green and sustainable strategy that reduces the use of toxic chemicals and offers a cost-effective alternative to conventional synthesis methods. In this context, the present study focused on the green synthesis of zinc oxide nanoparticles (ZnO-NPs) utilizing melon (Cucumis melo) peel and mint (Mentha piperita L.) stem extracts as biological reducing and stabilizing agents. Physicochemical properties of the synthesized ZnO-NPs were characterized using UV-Visible spectrophotometry, Fourier-transform infrared (FTIR) spectroscopy, scanning electron microscopy (SEM), and energy-dispersive X-ray (EDX) analysis. Following this, antimicrobial, antioxidant, and photocatalytic activities were evaluated. The results revealed that the average size of NPs was in the range of 35.8–46.5 nm. Both melon and mint derived ZnO-NPs (Me-ZnO-NPs and Mi-ZnO-NPs) showed strong antioxidant activity up to 41% and 83.5%, respectively. When tested against Enterococcus faecalis, Mi-ZnO-NPs demonstrated concentration-dependent effect against bacterial growth while Me-ZnO-NPs showed limited antibacterial effect. Moreover, both NPs found to mediate degradation of synthetic dyes under visible light within 48 h. The degradation efficiency against methylene blue, eosin-Y, and malachite green was found to be 73.7%, 81.2%, and 49.3% (for Mi-ZnO-NPs) and 67%, 65.6%, and 49.07% (for Me-ZnO-NPs), respectively. Hence, the present study effectively utilized agro-waste for ZnO-NPs production which can be useful for diverse biomedical and environmental applications.
Nasir et al. (Sat,) studied this question.