Rosemary essential oil nanoparticles enhance antimicrobial activity and induce bacterial DNA disruption

of approximately 6.06 mg/ml on Wi-38. In contrast, the Ros-ES-NPs not only showed no toxicity but actually appeared to increase cell viability (up to ≈ 136%) possibly due to high metabolic actvity.The antimicrobial activity of Ros-ES and Ros-ES-NPs was evaluated against three isolates of Multidrug-Resistant Bacteria, comprising two Gram-negative isolates (Shigella flexneri and Klebsiella pneumoniae) and one Gram-positive isolate (Streptococcus pneumoniae), alongside Candida albicans as the fungal pathogen. Ros-ES-NPs showed a significant antimicrobial efficacy against all isolates under study where, at 25 mg/ml, Ros-ES inhibited K. pneumoniae and Shigella flexneri by 55.16 ± 0.09% and 76.47 ± 1.16%, respectively, whereas Ros-ES-NPs showed inhibition rates of 95.66 ± 9.74% and 87.13 ± 2.63%, respectively. Against Streptococcus pneumoniae, at 25 mg/ml, Ros-ES inhibited by 68.75 ± 0.60%, while Ros-ES-NPs exhibited a higher inhibition rate of 80.73 ± 5.6%. In case of C. albicans, Ros-Es showed a higher inhibition (81.85 ± 0.54) than Ros-Es-NPs (60.39 ± 5.69). Rosemary essential oil nano-formulation significantly enhances antibacterial efficacy while improving biocompatibility and inducing pronounced microbial DNA damage.