Phyto-Fabrication of Iron Oxide Heterophase Nanocomposite Using Mentha arvensis Biomass: A Green Therapeutic Strategy for Balancing Natural Oral and Gastrointestinal Bacteria

Bacterial infections, predominantly affecting the gastrointestinal tract and oral cavity, represent a considerable health burden and remain among the leading causes of morbidity and mortality globally. Exploration of therapeutic mediators from medicinal plants continues to be a foundational strategy in modern drug development. The objective of the current study was to synthesize a Mentha arvensis-mediated biogenic iron oxide heterophase nanocomposite as a green therapeutic approach to controlling oral and gastrointestinal (GI) bacteria. Green synthesis is sustainable and an economic alternative for producing nanoparticles, because it is ecologically benign. For the first time native Al-Baha M. arvensis biomass was used for green preparation of mixed-phase iron oxide nanoparticles, and these were characterized by visual observation, X-ray diffraction, scanning electron microscopy, and Energy-Dispersive X-ray and FT-IR spectroscopy. The materialization of a dark brown color preliminarily points toward the establishment of iron oxide heterophase NPs due to reduction by phytochemicals. SEM demonstrated particle sizes approximately ranging between 30 and 80 nm, whereas EDX evidenced the predominance of Fe and O in the nanocomposite. Iron oxide heterophase NPs were also tested against human pathogens. The results displayed effective antibacterial activity, which seems concentration-dependent. The largest zone was recorded for S. aureus, with a size of 25 mm, and the smallest zone for L. garvieae at 100 µg/mL, with a size of 11 mm. The findings of this study indicate that iron oxide heterophase composites possess potential as biogenic antibacterial agents with environmentally friendly properties. Further development and optimization of this nanocomposite could contribute meaningfully to advancements in pharmaceutical and medical areas.