Synergistic antibacterial effects and metabolomic insights in Cyperus esculentus L. leaf-stem extracts against...

The rising threat of antimicrobial resistance necessitates sustainable alternatives to synthetic antibiotics, driving interest in plant-derived compounds for livestock feed. Cyperus esculentus L. (tiger nut) exhibits promising antibacterial properties, yet gaps persist in understanding its specific bioactive components, synergistic mechanisms, and metabolic impact on bacterial pathogens.

This study employed metabolomic profiling combined with bioassays to evaluate the efficacy of tuber, stem/leaf, and composite extracts against Staphylococcus aureus. Methods included Kirby-Bauer assays, scanning electron microscopy (SEM), growth curve analysis, response surface optimization, and wide-targeted metabolomics.

Key findings revealed: (1) Stem/leaf extracts outperformed tuber extracts in antibacterial activity, with their combination yielding synergistic effects; (2) Flavonoids (naringenin, acacetin, diosmetin, silybin A) demonstrated dose-dependent inhibition, disrupting cell wall/membrane integrity via SEM-confirmed morphological damage; (3) Optimal synergistic mix (2.84 μg/mL naringenin, 2.68 μg/mL acacetin, 3.04 μg/mL diosmetin, 3.08 μg/mL silybin A) achieved potent suppression across bacterial growth phases; (4) Metabolomic perturbations implicated sulfur metabolism, oxidative stress responses, and lipid remodeling in antibiosis.

This work uniquely establishes C. esculentus stem/leaf extracts as high-value, resource-efficient antibiotic alternatives for animal feed, leveraging synergistic phytochemistry and mechanistic insights to combat antimicrobial resistance.