A cocoa (Theobroma cacao L.) extract impairs the growth, virulence properties, and inflammatory potential of Fusobacterium nucleatum and improves oral epithelial barrier function

Abstract

Fusobacterium nucleatum is associated with many conditions and diseases, including periodontal diseases that affect tooth-supporting tissues. The aim of the present study was to investigate the effects of a cocoa extract (Theobroma cacao L.) on F. nucleatum with respect to growth, biofilm formation, adherence, and hydrogen sulfide (H2S) production. The anti-inflammatory properties and the effect on epithelial barrier function of the cocoa extract were also assessed. The cocoa extract, whose major phenolic compound is epicatechin, dose-dependently inhibited the growth, biofilm formation, adherence properties (basement membrane matrix, oral epithelial cells), and H2S production of F. nucleatum. It also decreased IL-6 and IL-8 production by F. nucleatum-stimulated oral epithelial cells and inhibited F. nucleatum-induced NF-κB activation in monocytes. Lastly, the cocoa extract enhanced the barrier function of an oral epithelial model by increasing the transepithelial electrical resistance. We provide evidence that the beneficial properties of an epicatechin-rich cocoa extract may be useful for preventing and/or treating periodontal diseases.

A Phenolic-rich Extract of Cocoa (Theobroma cacao L.) Beans Impairs the Pathogenic Properties of Porphyromonas gingivalis and Attenuates the Activation of Nuclear Factor Kappa B in a Monocyte Model

“…The effect of the cocoa extract (3.9, 7.81, 15.625, 31.25, 62.5, 125 μg/mL) on P. gingivalis -induced NF-κB activation was assessed. These concentrations were found to be non-cytotoxic in a previous study [ 27 ]. The monocyte suspension (50 μL, 3 × 10 6 cells/mL) was seeded in the wells of a black bottom, black wall 96-well microplate (Greiner Bio-One North America).…”

“…Since no MBC value was obtained, it suggests that the cocoa extract has a bacteriostatic mode of action, although a bactericidal effect may be obtained at concentrations >2,000 μg/mL. Given that the cocoa extract contains a variety of polyphenols [ 27 ], it is likely that the antibacterial mechanism of action against P. gingivalis involves different targets. However, the growth inhibitory effect may be related to the ability of epicatechin, which is the main phenolic compound in the cocoa extract, to bind to the lipid bilayer of the bacterial membrane, resulting in the disruption of the cell structure, leading to cell death [ 32 ].…”

“…However, the growth inhibitory effect may be related to the ability of epicatechin, which is the main phenolic compound in the cocoa extract, to bind to the lipid bilayer of the bacterial membrane, resulting in the disruption of the cell structure, leading to cell death [ 32 ]. Previous studies have also reported that cocoa extracts exert antibacterial activity against periodontal pathogens, including Fusobacterium nucleatum, Prevotella intermedia , and P. gingivalis [ 27 , 33 ].…”

“…A stock solution (20 mg/mL) was prepared in 10% dimethylsulfoxide (DMSO), sterilized by filtration (0.22 μm pore size), and kept at 4°C protected from light for up to 1 month. The phenolic characterization of the cocoa extract, as determined by chromatographic and mass spectrometry analyses, has been reported in a previous study [ 27 ]. The extract contains 30.93% (w/w) of polyphenols.…”

“…The basolateral and apical chambers were filled with 0.6 mL and 0.1 mL of culture medium, respectively. After a 72-h incubation (37°C/5% CO 2 ), the culture medium was replaced with fresh antibiotic-free K-SFM, and the cells were incubated for a further 16 h. Non-cytotoxic concentrations of the cocoa extract (31.25, 62.5, 125 μg/mL) identified in a previous study [ 27 ] were added to the apical chamber along with P. gingivalis at a multiplicity of infection (MOI) of 10 4 . The barrier function of the keratinocyte model was assessed by monitoring the transepithelial electrical resistance (TEER) at time 0 and after a 48-h incubation (37°C/5% CO 2 ) using an ohmmeter (EVOM2, World Precision Instruments, Sarasota, FL, USA).…”