| Abstrakt: |
The global rise of multidrug-resistant bacteria poses a significant threat to One Health, emphasizing the urgent need for alternative antibacterial agents. Essential oils (EOs) are potent antimicrobials. However, their use is limited by their volatility and hydrophobicity. We formulated stable oil-in-water (O/W) nanoemulsions (NEs) using blends of thyme, cinnamon bark, black pepper, and garlic EOs, employing high-energy ultrasonication. These NEs formed droplets between 44 and 88 nm, with a polydispersity index of 0.2–0.3. They remained thermodynamically stable for 3 months after heating–cooling and freeze–thaw cycles, outperforming conventional formulations. Key volatile components identified in the NEs included thymol, carvacrol, caryophyllene, E-cinnamaldehyde, and sulfur derivatives, which likely enhanced their bioactivity. These NEs exhibited over a 16-fold increase in free radical scavenging compared to blended and pure EOs, as measured by DPPH and ABTS assays. We also observed enhanced antibacterial effects. MIC values against an ESBL-resistant strain of K. pneumoniae were halved from 1.25 to 0.625 mg/ml. For E. coli, S. aureus, and S. Typhimurium, they decreased from 0.625 to 0.312 mg/ml. The enhanced efficacy is attributed to synergistic interactions within the NEs and an increased surface area. This facilitated bacterial membrane permeability and disruption, as shown by scanning electron microscopy. This approach offers a promising alternative to conventional antibiotics, particularly in food and poultry feed applications. [ABSTRACT FROM AUTHOR] |
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