BACKGROUND: Porphyromonas gingivalis is a major aetiological agent of periodontitis, a destructive disease affecting the tooth-supporting tissues. Recent reports have indicated that high-molecular-weight molecules from cranberry juice concentrate can prevent the attachment of human pathogens to host tissues.

OBJECTIVES: The aim of the present study was to investigate the effect of non-dialysable material (NDM) prepared from cranberry juice concentrate on growth, biofilm formation and adherence properties of P. gingivalis.

METHODS: The effect of cranberry NDM on biofilm formation was studied using a polystyrene microplate assay and by scanning electron microscopy. The effect of cranberry NDM on the attachment properties of P. gingivalis was evaluated by a microplate assay in which mammalian proteins were immobilized into wells.

RESULTS: Our results indicated that cranberry NDM is a potent inhibitor of biofilm formation by P. gingivalis. However, it has no effect on growth and viability of bacteria. Cranberry NDM also prevented significantly the attachment of P. gingivalis to surfaces coated with type I collagen, fibrinogen or human serum.

CONCLUSIONS: Our data suggest that cranberry constituents may have a beneficial effect for the prevention and treatment of periodontitis by reducing the capacity of P. gingivalis to colonize periodontal sites.