Evaluation of an aqueous-ethanolic extract from Pelargonium sidoides (EPs® 7630) for its activity against group A-streptococci adhesion to human HEp-2 epithelial cells

Aim of the study

The root extract of Pelargonium sidoides DC (Geraniaceae), EPs^® 7630, is currently used to treat respiratory tract infections. The therapeutic benefits are largely related to the modulation of the non-specific immune system. The present study was designed to investigate the anti-adhesive activity of this herbal medicine with Streptococcus pyogenes as model microorganism and to identify the underlying biologically active principle.

Materials and methods

Adherence of fluorescent-labelled group A-streptococci (GAS) to human epithelial (HEp-2) cells was assessed by flow cytometry. Anti-adhesive properties of the parent extract as well as a methanol-soluble (MSF) and a methanol-insoluble fraction (MIF) derived thereof were examined. Treatment with skin powder produced polyphenol-free samples which were included for comparison. Anti-adherence studies were extended to a series of highly purified proanthocyanidins including homogenous epicatechin- and catechin-based polyflavans, a ‘mixed’ procyanidin sample, an A-type proanthocyanidin mixture as well as a prodelphinidin test substance.

Results

After pre-treatment of GAS with EPs^® 7630 or its subfractions MIF and MSF at concentrations of 30 μg/ml, adhesion of the pathogen to HEp-2 cells was inhibited by ca. 45%, ca. 35% and ca. 30%, respectively. However, following preincubation of cells with the extract and the fractions no effect was observed. This finding indicates that the anti-adhesive effects are due to interactions with binding factors on the bacterial surface. Since polyphenol-free samples proved to be inactive, proanthocyanidins appear to represent the anti-adhesive principle. Comparative studies with chemically defined proanthocyanidins revealed that the prodelphinidin nature, i.e. the pyrogallol B-ring elements of constituent flavanyl units, represented an important structural feature of the anti-adhesive potential of this herbal medicine.

Conclusions

The current data provide strong evidence for a potent anti-adhesion principle of the Pelargonium sidoides root extract related to specific proanthocyanidins. This finding suggests an interaction with bacterial binding sites in a specific rather than non-specific manner. However, the blocked adhesion molecules remain to be identified. The anti-adhesive mechanism may well contribute to the anti-infective activity of EPs^® 7630 at an early time point of a bacterial infection.     

The patterns of MHC association in aplastic and non-aplastic paroxysmal nocturnal hemoglobinuria

The deficiency of glycosyl-phosphatidylinositol (GPI)-anchored proteins in plasma membranes of PIG-A gene mutated hematopoietic stem cells (HSCs) is so far insufficient to explain the domination of paroxysmal nocturnal hemoglobinuria (PNH) clone over the normal HSC. We attempted to elucidate possible link between MHC and initial severe aplastic anemia (ISAA/PNH) type and non-aplastic (n/PNH) outcome of PNH. In 50 PNH patients assigned as ISAA/PNH (n?=?13), n/PNH (n?=?33) or nonassigned (n?=?4) and 200 ethnically matched controls we analyzed MHC associations. Our data confirmed strong associations of DRB1*15:01 (RR?=?3.51, p?=?0.0011) and DQB1*06:02 (RR?=?7.09, p?=?0.000026) alleles, especially with n/PNH subtype. B*18:01 allele was associated with increased risk of ISAA/PNH subtype (RR?=?5.25, p?=?0.0028). We conclude that both class II and class I MHC alleles are associated with different subsets of PNH. Clonal selection of PIG-A mutated cells with cognate metabolic block is associated with MHC class II alleles DRB1*15:01 and DQB1*06:02 independent from initial severe AA clone selection. MHC class I molecule B*18:01 can additionally influence the domination of PNH clone in PNH subjects with initial severe aplastic anemia.     

IL4 gene polymorphisms and their relation to periodontal disease in a Macedonian population

Genetic polymorphisms in the interleukin-4 (IL4) gene have been reported to influence the host response to microbial challenge by altering levels of cytokine expression. We analyzed nucleotide polymorphisms in the promoter region of the IL4 gene and its relation with periodontal disease in a Macedonian population. The study population consisted of 92 unrelated subjects with chronic periodontitis and 286 healthy controls. DNA was isolated and IL4 genotyping performed by polymerase chain reaction-single-strand polymorphism (Heidelberg kit) for the alleles and genotypes of IL4 -1098, IL4 -590, and IL4 -33. Frequencies of IL4 haplotypes and the haplotype zygotes were also examined. Comparisons between groups were tested using the Pearson's p value. After Bonferroni adjustment, significant associations were detected between subjects with periodontitis and the following: (1) cytokine alleles IL4 -1098 and IL4 -33; (2) cytokine genotypes IL4 -1098/G:T; IL4 -1098/T:T, and IL4 -33/T:T, (3) cytokine haplotypes IL4/GCC, IL4/TCC, and IL4/TTC; and (4) cytokine haplotype zygotes IL4/TTC: TCC, IL4/TCT:TTT, and IL4/GCC:TTC. Cytokine polymorphism on the IL4 gene appears to be associated with susceptibility to chronic periodontitis in Macedonians.     

Divergent effects of age on performance in spatial associative learning and real idiothetic memory in humans

This study focuses on age-related differences concerning two kinds of spatial memory assessed by: (1) Paired Associates Learning (PAL) test from the CANTAB and (2) a test of Real Idiothetic Memory (RIM) using real-life settings. Despite a clear age-related drop in PAL that is reported in existing studies, age-related differences in idiothetic navigation still remain unclear. In our study we tested 80 healthy volunteers classified according to their age into two groups, i.e. young (aged from 20 to 29 years of life; n=40; 20M/20F) and elderly (from 64 to 77 years; n=40; 20M/20F) healthy volunteers. They were asked in the PAL test to remember the spatial location of visual patterns presented on a computer screen, and in the RIM test to walk on the arena in darkness in order to find a cue place and then to return to the start/exit point. A white noise was switched on at entering the cue place and switched off at leaving this place. Elderly subjects indicated poorer performance than their younger counterparts on the PAL test, as evidenced by all tested outcome measures. In contrast, for the RIM test no clear age effect was evidenced. In both tests no gender effect was observed. A dissociation in age-related changes for these two tests indicates that visuo-spatial associative learning and idiothetic navigation may have different cognitive control which is probably rooted in an interplay of different brain structures.