Effects of the French pine tree extract on Porphyromonas gingivalis

Pycnogenol®, a phytochemical extract from bark of the French maritime pine tree (Pinus pinaster Aiton), consists of standardized proportions of monomeric and oligomeric procyanidins and phenolic acids, which are categorized into polyphenol. Various components of polyphenols have been reported to have antibacterial effects. Objectives: The aim of this study is to examine the antibacterial activity of the French pine tree extract against oral bacteria and to evaluate the inhibitory effect on biofilm formation by Porphyromonas gingivalis. Methods: Antibacterial activity was determined by relative viability of each bacterium treated with the extract. For biofilm formation assay, P. gingivalis was cultured in BHI broth with 0.05% or 0.1% of the pine tree extract on culture plates. Media and unattached bacterial cells were removed and the plates were stained with crystal violet. Biofilm formation was quantified by measuring the absorbance of bound dye to P. gingivalis. Coaggregation of P. gingivalis with other bacteria was examined by the visual coaggregation assay. Results: Gram positive bacteria except A. viscosus tested in this study were susceptible to 0.1% (w/v) concentration of the extract and the efficacy against Streptococcus mutans was observed at least 0.05% concentration. The drastic antibacterial activity of this material was observed against Gram negative rods at 0.1% concentration. Especially, black-pigmented P. gingivalis and Prevotella nigrescens were highly susceptible to the extract. Addition of the extract to bacterial culture reduced the number of P. gingivalis adhered by using culture plate system. Furthermore, pretreatment of P. gingivalis with 0.05% of the material resulted in the inhibition of coaggregation with Gram positive oral bacteria. Conclusion: The study suggest that the French pine tree extract may contribute to prevent oral infections, as results of having antibacterial activity against various species of oral microorganisms, blocking biofilm formation and coaggregation by P. gingivalis.