Planta Med 2013; 79 - PJ6
DOI: 10.1055/s-0033-1352210

Proteinase-inhibiting activity of an extract of Rumex acetosa L. against virulence factors of Porphyromonas gingivalis

S Beckert 1, A Hensel 1
  • 1Institute of Pharmaceutical Biology and Phytochemistry, University of Münster, D-48149 Münster, Germany

Periodontitis is a disease with considerable impact on the whole organism and worldwide prevalence. The gram-negative bacterium Porphyromonas gingivalis is regarded as one of its main etiological agents. Essential for the progression of this disease are highly specialized virulence factors of P. gingivalis, Lys-gingipain (Kgp) and Arg-gingipain (Rgp). Both proteinases are involved in the process of adhesion to host cells, in the bacterial invasion into the cells, acquisition of nutrients and the modulation of the host's local immune response.

In the context of developing oral hygiene products with antiadhesive activity against P. gingivalis a proanthocyanidin-rich acetone-water extract (7:3) of Rumex acetosa L. (Polygonaceae) [1] proved to be highly effective under in vitro conditions. Treatment of P. gingivalis with the extract led to concentration dependant gingipain inhibition. Especially Rgp activity was inhibited, by approximately 20, 60 and 80% at extract concentrations of 5, 10 and 50 µg/mL. For pinpointing active principles, dimeric and trimeric proanthocyanidins were isolated and their structural features characterized. Their influence on Kgp and Rgp activity was determined. While procyanidin B2 had no significant effect, epicatechin-3-O-gallate-(4b→8)-epicatechin-3-O-gallate showed about 80% inhibition of Rgp at a concentration of 5µM. An isolated A-type procyanidin, epicatechin-(2b→7, 4b→8)- epicatechin-(4b→8)-epicatechin, inhibited Rgp selectively, without influencing Kgp. Therefore unspecific tannin-like astringent effects as reason for gingipain inhibition can be excluded with the utmost probability.

Corresponding structure-activity relations can be used for development of novel inhibitors of bacterial gingipains for oral application.

Reference:

[1] Bicker A, Petereit F, Hensel A (2009) Proanthocyanidins and a phloroglucinol derivative from Rumex acetosa L. Fitoterapia. 80(8); 483 – 95.