Disclosing the Functional Potency of Three Oxygenated Monoterpenes in Combating Microbial Pathogenesis: From Targeting Virulence Factors to Chicken Meat Preservation

Abstract

During the last few decades, there has existed an increased interest in and considerable consumer preference towards using natural and safe compounds derived from medicinal plants as alternatives to synthetic preservatives to combat microbial pathogenicity. In this regard, the present study investigated the possible synergistic interactions of the anti-foodborne bacterial capacity of linalool (L), eucalyptol (E), and camphor (C). The antibacterial synergistic effect was determined against Staphylococcus aureus, Listeria monocytogenes, Salmonella enterica Typhimurium, and Escherichia coli. The optimal predicted mixture showed the highest antibacterial activity at 33.5%, 33.2%, and 33.4% of L, E, and C, respectively. Molecular docking simulations displayed that the studied monoterpenes have effective antibacterial inhibitory effects by impeding specific virulence factors such as sortase A, listeriolysin O, L, D-Transpeptidase, and polyphosphate kinase. The selected triple combination of L, E, and C was applied as a natural preservative in minced chicken breast meat. In this regard, 1 MIC (16 µg/mL), 1.5 MIC (24 µg/mL), and 2 MIC (32 µg/mL) of L. monocytogenes were used, and the microbiological, physicochemical, and sensory analyses were monitored for 14 days of storage at 4 °C. The L/E/C mixture at different levels could delay lipid and protein oxidation, inhibit the microorganisms, and maintain the sensory attributes. Additionally, by using chemometric tools, strong connections between physicochemical properties, microbiological parameters, and organoleptic attributes were established. Concisely, this research confers the importance of the use of blended monoterpenes and highlights their antibacterial mode of action, effectiveness, and synergistic effects as a powerful and safe bio-preservative formulation in chicken meat products.

Keywords: bio-preservation; chemometric analysis; mixture design; molecular docking; oxygenated monoterpenes; virulence factors.

Figure 1

Contour plots for the effects of different compounds mixtures on S. aureus (a), S. enterica Typhimurium (b), E. coli (c), and L. monocytogenes (d). Results are expressed by MIC (µg/mL).

Figure 2

Response optimizer at the optimum conditions for the maximum response.

Figure 3

Interaction complexes of linalool (A), eucalyptol (B), and camphor (C) with the Sortase A protein of S. aureus.

Figure 4

Interaction complexes of linalool (A), eucalyptol (B), and camphor (C) with the YcbB protein of S. enterica Typhimurium.

Figure 5

Interaction complexes of linalool (A), eucalyptol (B), and camphor (C) with the listeriolysin O protein of L. monocytogenes.

Figure 6

Interaction complexes of linalool (A), eucalyptol (B), and camphor (C) with the PPK protein of E. coli.

Figure 7

Principal component analysis representing the distribution of the different samples and storage days (A,B) and the microbial, physicochemical, and descriptive sensory parameter loadings (C).