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Aims: Aqueous extracts from the roots of Glycyrrhiza glabra L. (Fabaceae) are widely used for treatment of stomach ulcer. The clinical proven effects are related to the presence of anti-inflammatory 12-keto-triterpensaponins in the extracts. Apart from that the influence of Glycyrrhiza glabra extract on the bacterial adhesion of Helicobacter pylori to stomach tissue was to be investigated. Additionally the influence of Glycyrrhiza glabra secondary compounds on the bacterial adhesion of Porphyromonas gingivalis, a major pathogen for induction of periodontal inflammations was to be investigated., Methodology: In vitro cytotoxicity against Helicobacter pylori was investigated by agar diffusion assay; antiadhesive properties of aqueous extract, raw polysaccharides and purified polysaccharide fractions was investigated by means of an in situ adhesion assay with FITC-labelled bacteria on tissue slides of human stomach resectates., Results: Aqueous extract (1mg/mL) of Glycyrrhiza glabra significantly inhibited the adhesion of Helicobacter pylori to human stomach tissue. This effect was related to the polysaccharides isolated from the extract, with one purified acidic fraction (0.25 SPB) as main active polymer. Purified polysaccharides did not exhibit direct cytotoxic effects against Helicobacter pylori and did not influence hemagglutination. Additionally raw polysaccharides from Glycyrrhiza glabra were shown to have strong antiadhesive effects against Porphyromonas gingivalis., Conclusion: Aqueous extracts and polysaccharides from the roots of Glycyrrhiza glabra are strong antiadhesive systems, which may be used as potent tools for a further development of cytoprotective preparations with anti-infectious potential.

Root extract from Pelargonium sidoides DC is used therapeutically as antimicrobial agent against infections of the respiratory system. In order to elucidate possible modes of actions we investigated the influence of P. sidoides root extract on microbial adhesion with Helicobacter pylori as model microorganism, a germ with a strong adherence to human stomach tissue. In an in-situ anti-adhesion assay intact human stomach tissue from patient resectates was incubated with fluorescent-labelled bacteria. Epithelial adhesion occurred in untreated samples and was quantified by fluorescent microscopy. Pre-treatment of the bacteria with Pelargonium extract showed good anti-adhesive activity. The antiadhesive effect was clearly dose-dependent in a range from 0.001 to 10 mg/ml. Within agar diffusion-test the extract had no direct cytotoxicity against H. pylori. The results show that the root extract from Pelargonium sidoides is a potent anti-adhesive agent against H. pylori and could therefore be a useful choice to avoid the first step of a bacterial infection.