Nanowarriors from Mentha: Unleashing Nature’s Antimicrobial Arsenal with Cerium Oxide Nanoparticles

Medicinal plant-based cerium oxide nanoparticles (CeO(2)NPs) possessed excellent antimicrobial properties against multiple strains of Gram-positive and Gram-negative bacteria. The CeO(2)NPs are popular because their electropositive charged surface causes oxidation of plasma membrane and facilitates the penetration of CeO(2)NPs inside the pathogen body. In the present research work, CeO(2)NPs stabilized with Mentha leaf extract; as a result, nanoparticles surface-bonded with various functional groups of phytochemicals which enhanced the therapeutic potential of CeO(2)NPs. The inhibition percentage of CeO(2)NPs was evaluated against eight pathogenic Gram-positive bacteria Staphylococcus aureus and Streptococcus epidermidis; Gram-negative bacteria Escherichia coli, Stenotrophomonas maltophilia, Comamonas sp., Halobacterium sp., and Klebsiella pneumoniae; and plant bacteria Xanthomonas sp. The antifungal properties of CeO(2)NPs were evaluated against three pathogenic fungal species Bipolaris sorokiniana, Aspergillus flavus, and Fusarium oxysporum via the streak plate method. The antimicrobial inhibitory activity of CeO(2)NPs was good to excellent. The current research work clearly shows that three different medicinal plants Mentha royleana, Mentha longifolia, and Mentha arvensis based CeO(2)NPs, variation in nanoparticle sizes, and surface-to-volume ratio of green CeO(2)NPs are three factors responsible to generate and provoke antimicrobial activities of CeO(2)NPs against human pathogenic bacteria and plant infecting fungi. The results show that CeO(2)NPs possessed good antimicrobial properties and are effective to use for pharmaceutical applications and as a food preservative because of low toxicity, organic coating, and acceptable antimicrobial properties. This study showed a rapid and well-organized method to prepare stable phytochemical-coated CeO(2)NPs with three different plants M. royleana, M. longifolia, and M. arvensis with remarkable antibacterial and antifungal characteristics.