Effects of Geum urbanum L. root extracts and its constituents on polymorphonuclear leucocytes functions. Significance in periodontal diseases.

ETHNOPHARMACOLOGICAL RELEVANCE: Geum urbanum L. (wood avens) root infusions and decoctions have been used externally for reducing the bleeding and inflammation of gums (gingivitis), and mucous membranes.

AIM OF THE STUDY: Taking into account that primed and hyperactivated neutrophils are an important factor in the transition from gingivitis to periodontitis, we investigated the effects of phytochemically characterised (HPLC-DAD-MS(n)) extracts of different polarity from Geum urbanum root on oxidative burst, elastase, metalloproteinase 9 (MMP-9), interleukin 8 (IL-8) and 1β (IL-1β), tumour necrosis factor (TNF-α) release, expression of adhesion molecules (CD62L and CD11b) and delayed apoptosis in stimulated neutrophils. As gemin A is a dominating compound in a raw material, so we considered its activity in parallel with the positive control quercetin.

MATERIALS AND METHODS: The extracts were characterised by HPLC-DAD- MS(n) method. The inhibition of ROS production by stimulated neutrophils was determined using luminol dependent chemiluminescence method. The effect on MMP-9, IL-1β, TNF-α and IL-8 production by neutrophils was measured by enzyme-linked immunosorbent assay (ELISA). Neutrophil elastase release was established spectrophotometrically. The expression of adhesion molecules and the apoptosis of neutrophils was analyzed with flow cytometry.

RESULTS: The main compounds detected in the extract belong mainly to the group of ellagitannin: pedunculagin, stachyurin, casuarynin and gemin A, and ellagic acid derivatives. Procyanidins and one complex tannin were found as minor compounds. Gemin A significantly affected the functions of stimulated neutrophils by reducing the surface expression of CD11b, and inhibiting the release of reactive oxygen species, and proteases (elastase, MMP-9), chemokines and cytokines (interleukins IL-8, IL-1β). Interestingly, gemin A stimulated the release of TNF-α, which may be one of the stimulators of apoptosis of neutrophil cells. The primary aqueous extract, the ethyl acetate and the butanolic fractions, all containing the highest level of gemin A, have exerted similar but weaker activity.

CONCLUSION: The modulating effect on the neutrophils function of extracts, and its main constituent gemin A, support the traditional use of this plant material in cavity inflammation including mucositis, gingivitis and periodontosis.