Sessions

The escalating prevalence of antimicrobial resistance in human and veterinary medicine underscores the urgent need for innovative therapeutic strategies. Plant-derived essential oils have demonstrated promising antimicrobial properties, yet their clinical application is limited by volatility, low solubility, and instability. Nano-encapsulation is a key strategy to enhance their stability and efficacy.

This study compared the in vitro antimicrobial activity of free and nano-encapsulated cinnamon and lemongrass oil against two swine pathogens, Escherichia coli and Clostridium perfringens. The aim was to determine whether lower concentrations of nano-formulated oils could achieve equivalent or improved efficacy, potentially offering financial advantages. Bacterial growth inhibition was assessed using the broth microdilution method, and minimum inhibitory concentrations (MIC) were determined.

Results indicated a general concentration-dependent inhibition for all treatments, although nano-encapsulation was not consistently more effective than the free form. Against E. coli, cinnamon oil was more potent than lemongrass oil. The free form of cinnamon slightly outperformed its nano-formulated counterpart, as the MIC increased from 0.3125 mg/mL to 0.5 mg/mL. However, nano-formulation enhanced the activity of lemongrass, decreasing MIC from 5 mg/mL to 2 mg/mL. For C. perfringens, cinnamon remained more potent than lemongrass, with negligible differences between the MIC of the free (0.039 mg/mL) and the encapsulated forms (0.0312 mg/mL). Encapsulation markedly enhanced lemongrass oil activity, reducing the MIC ten-fold from 2.5 mg/mL to 0.25 mg/mL.

The findings demonstrate that the antibacterial potential of nano-encapsulated essential oils is variable, with cinnamon oil inherently potent, while nano-encapsulation notably enhanced the efficacy of lemongrass oil, highlighting their potential as alternative antimicrobial agents. Further in vivo studies are warranted to explore their therapeutic application.