The anthraquinone rhein exhibits synergistic antibacterial activity in association with metronidazole or natural compounds and attenuates virulence gene expression in Porphyromonas gingivalis.
Arch Oral Biol
; 60(2): 342-6, 2015 Feb.
Article
en En
| MEDLINE
| ID: mdl-25463909
ABSTRACT
OBJECTIVE:
Rhein is a major anthraquinone found in rhubarb root. As a continuation of our ongoing studies aimed to identify beneficial properties of this anthraquinone for periodontal disease, in this study, we investigated the ability of rhein to (i) exhibit antibacterial synergy towards the periodontopathogen Porphyromonas gingivalis when used in combination with metronidazole or polyphenols belonging to different families, and (ii) attenuate virulence factor gene expression in P. gingivalis.METHODS:
The minimal inhibitory concentrations (MIC) of compounds under investigation were determined by a broth microdilution assay. The synergistic effects of rhein in association with either metronidazole or polyphenols of various families were evaluated using the chequerboard technique to determine the fractional inhibitory concentration index (FICI). The effect of rhein on virulence factor gene expression in P. gingivalis was determined by quantitative RT-PCR.RESULTS:
Rhein showed a MIC of 2.5 µg/mL, which was similar to that of metronidazole. Except for the association with epigallocatechin-3-gallate that gave an additive effect, all the other combinations (licochalcone A, glabridin, myricetin, and metronidazole) resulted in synergistic effects. The strongest synergy was observed when rhein was used in association with myricetin (FICI=0.12) and licochalcone A (FICI=0.19). At a sub-MIC of rhein (0.5 µg/mL), a significant decrease in the expression of fimA, hagA, and hagB genes, which are involved in host colonization, was observed. Moreover, the expression of rgpA and kgp, two protease genes related to inactivation of host defense mechanisms, tissue destruction, and nutrient acquisition, was also down-regulated.CONCLUSION:
The data presented in our study indicate that rhein possessed antibacterial activity, which can be potentiated in combination with metronidazole or other polyphenols. In addition, rhein can impair the pathogenicity of P. gingivalis by reducing transcription of genes coding for important virulence factors.Palabras clave
Texto completo:
1
Colección:
01-internacional
Base de datos:
MEDLINE
Asunto principal:
Antraquinonas
/
Porphyromonas gingivalis
/
Metronidazol
/
Antibacterianos
Tipo de estudio:
Prognostic_studies
/
Risk_factors_studies
Idioma:
En
Revista:
Arch Oral Biol
Año:
2015
Tipo del documento:
Article
País de afiliación:
Canadá