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Abstract
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Biofilms play a pivotal role in bacterial pathogenicity and antibiotic resistance, representing a major challenge in the treatment of bacterial infections. Among essential oil phytochemicals, trans-cinnamaldehyde (TC), a major component of Cinnamomum spp. essential oil, has been recognized for its antimicrobial and anti-biofilm activity [1]. However, its application has been limited due to its low bioavailability, high volatility and chemical reactivity. To overcome these limitations, oil-in-water nanoemulsion (NE)- based delivery system can be applied [2]. In this study, TCNE was prepared using a high energy sonication method with Tween 80, span 80 and lecithin. The mean particle size and polydispersity index of prepared nanoemulsion were 53.24±1.25 nm and 0.36±0.03 nm, respectively. Dynamic light scattering measurements over four weeks confirmed the long-term stability of formulation. Antibacterial activity of TC and TCNE were evaluated by determining the minimum inhibitory concentration (MIC) against Pseudomonas aeruginosa PAO1, which was found to be 2 mg/mL for TC and 1 mg/mL for TCNE. The biofilm inhibitory effects of TC and TCNE were evaluated using crystal violet staining assay at sub-inhibitory concentrations (1/2, 1/4 and 1/8 × MIC). Both TC and its NE exhibited concentration-dependent inhibitory effect, with the highest inhibition (83.4±1.81%) observed for TCNE at 1/2 ×MIC. Scanning electron microscopy further supported the inhibitory effect of TCNE on PAO1 biofilm. These results demonstrate the potential use of TCNE as a promising strategy for combating biofilm
associated bacterial infections.
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