Influence of Gallic Acid and Thai Culinary Essential Oils on Antibacterial Activity of Nisin against Streptococcus mutans

Abstract

Streptococcus mutans is a well-known oral pathogen commonly associated with a normal dental problem and life-threatening infection. A bacteriocin nisin and the plant-derived compounds including gallic acid (GA) and Thai culinary essential oils (EOs) have been reported to have activity against oral pathogens. However, their synergistic interaction against S. mutans has not been explored. The purposes of this study were primarily to investigate anti-S. mutans properties and the antibiofilm formation of nisin, GA, and five EOs by using the broth microdilution method. Besides, the morphological change, killing rate, and antibacterial synergism were determined by scanning electron microscopy (SEM), time-kill assay, and checkerboard method, respectively. The results demonstrated that kaffir lime leaf (KLL) oil, lemongrass (LG) oil, and GA showed a potent anti-S. mutans activity and inhibited biofilm formation with the possible mechanism targeted on the cell membrane. Additionally, KLL oil revealed anti-S. mutans synergism with GA, LG oil, and chlorhexidine with the fractional inhibitory concentration (FIC) indexes ≤ 0.5. Interestingly, GA displayed a high potential to enhance anti-S. mutans activity of nisin by lowering the minimum inhibitory concentrations (MICs) to at least 8-fold in a bacteriostatic manner. These results suggest that GA and KLL oil may be potentially used as an adjunctive therapy along with nisin and chlorhexidine to control S. mutans infection.

Enhancement of the Antibiofilm Activity of Nisin against Listeria monocytogenes Using Food Plant Extracts

“…Butyl gallate, a derivative of gallic acid, exhibited synergistic effects with nisin compared to other derivatives [ 50 ]. Additionally, the combination of gallic acid and certain natural extracts showed antimicrobial synergy against other pathogenic bacteria, including Pseudomonas aeruginosa and Staphylococcus aureus [ 51 , 52 ].…”

Essential Oil Modification of Glass Ionomer Cement: Antibacterial Activity and Compressive Strength

“…The major component of lemongrass as reported in table 3 is Z-Citral which represents more than 50% of the components. Z-citral is a monoterpene which causes loss of membrane integrity of bacterial cells increasing cell membrane permeability via hydrophobic interactions with the membrane 36,37 . It could also induce changes in the intracellular pH and intracellular ATP concentration in the bacterial cell as reported by De Silva et al, 2017 38 .…”

Alkyl Gallates as Potential Antibiofilm Agents: A Review

“…The antibacterial effects of GA have also been investigated for synergy with other agents. As mentioned, GA by itself has shown strong activity against S. mutans , inhibiting its biofilm formation and markedly enhancing the anti- S. mutans activity of the polypeptide nisin, decreasing the value of its MIC eightfold in a bacteriostatic manner [ 27 ]. However, Wang and Lam [ 18 ] found that GA also enhanced the aggregation and biofilm formation of Actinomyces naeslundii on abiotic surfaces by affecting physicochemical properties of the cell surface and changing the shape of the cell envelopes, causing a calcium efflux from the bacteria.…”