Antibacterial Efficacy of Ethanol Extracts from Edible Rumex madaio Root and Application Potential for Eliminating Staphylococcus aureus and Vibrio cholerae in Aquatic Products for Green Food Preservation

Edible and medicinal plants provide a treasure trove of natural phytochemicals for mining the next generation of green food preservatives. Herein, we evaluated antibacterial activities of 55-95% ethanol extracts from the edible rhizome of <i>Rumex madaio</i> (<i>Rm</i>EEs). The 75% ethanol extract displayed the strongest antibacterial activity, and its purified fraction 2 (<i>Rm</i>EE-F2) blocked the proliferation of common pathogens <i>Staphylococcus aureus</i> and <i>Vibrio cholerae</i>, with minimum inhibitory concentrations (MICs) of 391 μg/mL. <i>Rm</i>EE-F2 (1 × MIC) altered the bacterial cell surface biophysical parameters and impaired cell structure, resulting in intracellular nucleic acid and protein leakage. It manifested bacteriostatic rates of 88.21-91.17% against <i>S. aureus</i> and <i>V</i>. <i>cholerae</i> in spiked fish (<i>Carassius auratus</i>) and shrimp (<i>Penaeus vannamei</i>) during storage at 4 °C for 24 h. Meanwhile, <i>Rm</i>EE-F2 effectively rendered the pH rising and reduced lipid oxidation and protein degradation of <i>C. auratus</i> and <i>P. vannamei</i> meat samples at 4 °C for 6 days. Additionally, <i>Rm</i>EE-F2 (< 781 µg/mL) showed non-cytotoxicity to human colon Caco-2, liver HepG-2, and lung A549 cell lines, and rescued <i>V. cholerae</i> and <i>S. aureus</i>-infected Caco-2 cellcells with enhanced viability of 14.31-16.60% (1 × MIC). Comparative transcriptomic analysis revealed down-regulated protein synthesis, cell wall and cell membrane synthesis, and or DNA replication and repair in the tested bacteria triggered by <i>Rm</i>EE-F2. The major antibacterial compounds in <i>Rm</i>EE-F2 included melibiose (9.86%), 3-(N, N-dimethylaminomethyl) indole (7.12%), and citric acid (6.07%). Overall, this study underscores the promising potential of <i>Rm</i>EE-F2 for aquatic product green preservation.