Pomegranate-Derived Zinc Oxide Coupled with Red Cabbage and Beetroot for Potent Antimicrobial and Antioxidant Defense

The global rise of antibiotic-resistant pathogens and persistent microbial contamination urgently demands the development of safe, sustainable, and effective antimicrobial alternatives. Addressing this challenge, this study introduces a novel green synthesis of zinc oxide nanoparticles (ZnO NPs) using pomegranate peel extract, further enhanced through the incorporation of red cabbage (RC) and beetroot (BR) extracts—both rich in potent bioactive compounds. This innovative approach not only utilizes agricultural waste and natural antioxidants but also creates multifunctional nanocomposites with superior bioactivity. Structural characterization via FTIR and XRD confirmed that RC-ZnO NPs exhibited higher crystallinity and peak density, while BR-ZnO NPs showed distinct composite formation, both contributing to enhanced performance. RC-ZnO NPs demonstrated outstanding antioxidant activity with 92.03% DPPH radical scavenging and an IC50 of 1.93 mg/mL, surpassing BR-ZnO NPs (60.5%, IC50 3.013 mg/mL) and unmodified ZnO NPs. Antimicrobial tests revealed that RC-ZnO and BR-ZnO NPs significantly improved antibacterial activity, producing inhibition zones up to 21 mm against Bacillus cereus and Staphylococcus aureus , alongside strong antifungal effects against Penicillium roquefortii and Aspergillus niger . Furthermore, the composites effectively inhibited biofilm formation by up to 89.4%, and growth curve analysis confirmed substantial suppression of Staphylococcus aureus , supported by increased protein leakage from bacterial cells. These findings demonstrate the novelty and significance of combining ZnO NPs with plant-based extracts to create eco-friendly, high-performance nanocomposites, offering a promising strategy for combating resistant pathogens, controlling biofilms, and promoting sustainable solutions in food safety and healthcare applications.