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A Licorice Extract Reduces Lipopolysaccharide‐Induced Proinflammatory Cytokine Secretion by Macrophages and Whole Blood
Author(s) -
Bodet Charles,
La Vu Dang,
Gafner Stefan,
Bergeron Chantal,
Grenier Daniel
Publication year - 2008
Publication title -
journal of periodontology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.036
H-Index - 156
eISSN - 1943-3670
pISSN - 0022-3492
DOI - 10.1902/jop.2008.080052
Subject(s) - proinflammatory cytokine , aggregatibacter actinomycetemcomitans , porphyromonas gingivalis , tumor necrosis factor alpha , lipopolysaccharide , ex vivo , chemistry , pharmacology , inflammation , biology , immunology , periodontitis , medicine , biochemistry , in vitro
Background: Periodontal diseases are a group of inflammatory disorders initiated by specific Gram‐negative periodontopathogenic bacteria that lead to the destruction of tooth‐supporting tissues. In this study, we tested whether a carbon dioxide–supercritical extract of Glycyrrhiza uralensis (licorice) can reduce the periodontopathogen‐induced inflammatory response. Methods: Monocyte‐derived macrophages were treated with various concentrations of the licorice extract prior to being stimulated with Aggregatibacter actinomycetemcomitans (previously Actinobacillus actinomycetemcomitans ) and Porphyromonas gingivalis lipopolysaccharide (LPS). The capacity of the licorice extract to mediate the inflammatory response was also tested in an ex vivo whole blood model stimulated with P. gingivalis LPS. The secretion of interleukin (IL)‐1β, −6, and −8 and tumor necrosis factor‐alpha (TNF‐α) in both models was assessed by enzyme‐linked immunosorbent assays. Changes in the phosphorylation state of macrophage intracellular kinases induced by A. actinomycetemcomitans LPS and the licorice extract in the macrophage model were characterized by immunoblotting. Results: The licorice extract exhibited potent anti‐inflammatory properties, inhibiting the periodontopathogen LPS‐induced IL‐1β, −6, and −8 and TNF‐α responses of macrophages. The licorice extract inhibited the phosphorylation of important macrophage intracellular signaling proteins, including nuclear factor‐kappa B p65 nuclear transcription factor and Jun proto‐oncogene‐encoded activator protein (AP) 1 transcription factor, which are involved in inflammatory signaling pathways. The licorice extract was also a potent inhibitor of the proinflammatory cytokine response in the ex vivo human whole blood model. Conclusion: This CO 2 ‐supercritical licorice extract is a potential candidate for the development of a new therapy to prevent and/or treat periodontitis‐associated tissue destruction.