Prunella vulgaris extract and rosmarinic acid suppresse lipopolysaccharide-induced alteration in human gingival fibroblasts

Periodontitis is a chronic disease associated with inflammation of tooth supporting tissues. Dental plaque is one of the most contaminated materials and major contributor to the development of inflammatory reactions in the marginal parodont. Usually it contains more then 300 different bacterial species rendering a microbial count of up to 10¹¹ organisms per gram. These express a number of irritating agents including a lipopolysaccharide (LPS), which plays a key role in periodontal disease development. Plant extracts with anti-inflammatory and anti-microbial properties have been shown to inhibit bacterial plaque formation and thus to prevent chronic gingivitis. In this study we tested effects of Prunella vulgaris L. (Labiatae) ethanolic extract (PVE) and its main phenolic component rosmarinic acid (RA) on LPS-induced oxidative damage and inflammation markers in human gingival fibroblasts.

Gingival fibroblasts were pre-treated with LPS (0.1/1/10µg/ml; 4 or 24h) and then PVE (5, 10, 25µg/ml) or RA (1µg/ml) were applied for 4h. PVE and RA exhibited ability to reduce LPS-induced ROS production, GSH depletion as well as lipid peroxidation in cells. We also found that treatment with PVE and RA inhibited LPS-caused up-regulation of IL-1β, IL-6, TNF-a and suppressed expression of inducible nitric oxide synthase.

The results demonstrate that PVE and RA suppress all monitored LPS-initiated biological changes and prove antioxidant and anti-inflammatory effect of PVE and RA at the level of gingival fibroblasts. Use of PVE and RA may be relevant in modulation of inflammation process, including periodontal disease.

Acknowledgements: This work was supported by Ministry of Education of the Czech Republic (MSM 6198959216) and Faculty of Medicine and Dentistry of Palacký University (91110171).