Synergistic Antimicrobial Activities of Combinations of Vanillin and Essential Oils of Cinnamon Bark, Cinnamon Leaves, and Cloves

Abstract

Plant bioactive compounds have antimicrobial and antioxidant activities that allow them to be used as a substitute for synthetic chemical additives in both food and food packaging. To improve its sensory and bactericidal effects, its use in the form of effective combinations has emerged as an interesting possibility in the food industry. In this study, the antimicrobial activities of essential oils (EOs) of cinnamon bark, cinnamon leaves, and clove and the pure compounds vanillin, eugenol, and cinnamaldehyde were investigated individually and in combination against Listeria monocytogenes and Escherichia coli O157:H7. The possible interactions of combinations of pure compounds and EOs were performed by the two-dimensional checkerboard assay and isobologram methods. Vanillin exhibited the lowest antimicrobial activity (MIC of 3002 ppm against L. monocytogenes and 2795 ppm against E. coli O157:H7), while clove and cinnamon bark EOs exhibited the highest antimicrobial activity (402–404 against L. monocytogenes and 778–721 against E. coli O157:H7). For L. monocytogenes, pure compound eugenol, the main component of cinnamon leaves and clove, showed lower antimicrobial activity than EOs, which was attributed to the influence of the minor components of the EOs. The same was observed with cinnamaldehyde, the main component of cinnamon bark EO. The combinations of vanillin/clove EO and vanillin/cinnamon bark EO showed the most synergistic antimicrobial effect. The combination of the EOs of cinnamon bark/clove and cinnamon bark/cinnamon leaves showed additive effect against L. monocytogenes but indifferent effect against E. coli O157:H7. For L. monocytogenes, the best inhibitory effects were achieved by cinnamon bark EO (85 ppm)/vanillin (910 ppm) and clove EO (121 ppm)/vanillin (691 ppm) combinations. For E. coli, the inhibitory effects of clove EO (104 ppm)/vanillin (1006 ppm) and cinnamon leaves EO (118 ppm)/vanillin (979 ppm) combinations were noteworthy. Some of the tested combinations increased the antimicrobial effect and would allow the effective doses to be reduced, thereby offering possible new applications for food and active food packaging.

Combined antibacterial effect of Origanum essential oils and antibiotics against multiresistant foodborne Salmonella isolated from poultry and shellfish in Morocco

“…To the best of our knowledge, no prior research has claimed a synergy between Origanum EOs and antibiotics on multiresistant foodborne Salmonella in Morocco. Nonetheless, the majority of research focuses on the potential medical benefits of EOs either alone or when combined (Cava‐Roda et al, 2021; Fadil et al, 2018; Tardugno et al, 2018). Indeed, it is interesting to note that efforts have been made to investigate the bioactive characteristics of EOs from various Origanum species.…”

Effect of Essential Oils on Growth Inhibition, Biofilm Formation and Membrane Integrity of Escherichia coli and Staphylococcus aureus

“…Recent studies have shown that the mechanisms of action of phenolic monoterpene compounds in EOs are mainly associated with their activity on cell viability, and their interaction with transcriptional regulators of QS communication, biofilm formation, and virulence genes has been proposed [ 75 , 76 ]. In addition, it has been evidenced that the activity of the major components of an EO could be altered by its minor components, either in a synergistic, antagonistic, or neutral way, depending on the relative amount of these minor components [ 77 , 78 ]. Therefore, the effect of an EO could vary between microorganisms and even between different strains of the same microorganism [ 79 , 80 ].…”

Analysis of the Chemical Profiles and Anti-S. aureus Activities of Essential Oils Extracted from Different Parts of Three Oregano Cultivars

“…Given the heterogeneous composition of OEOs and the antimicrobial activities of many OEO components, it seems unlikely that there is only one mechanism of action or that only one component is responsible for the antimicrobial action. At the same time, the various chemical components contained in plant EOs often have synergistic effects, and the diversity of antibacterial targets can greatly reduce the resistance of bacteria [31,32].…”