New biological potential of abietane diterpenoids isolated from Salvia austriaca against microbial virulence factors.

The increasing importance of multi-resistant strains and microbial biofilms in the development of chronic infections has driven the search for more effective alternative therapy including plant-origin preparations. The present study evaluates the broadly-defined antimicrobial activity of two abietane diterpenoids isolated from Salvia austriaca transformed roots: taxodone and 15-deoxy-fuerstione. The direct biostatic/biocidal effect of these phytocompounds and their influence on Staphylococcus aureus and Candida albicans virulence factors/mechanisms (adhesion, biofilm formation, agglutination in human plasma, survival in the blood, germ tube and mycelium formation) were tested using in vitro assays. Both phytocompounds significantly inhibited microbial adhesion and biofilm formation when used at ½ and » MIC. Additionally, taxodone was able to limit staphylococcal survival in human blood, as well as C. albicans germ tube formation and hyphal growth. The tested diterpenoids express significant anti-biofilm activity against both staphylococci and yeast, and adversely affect their virulence factors/mechanisms, which are relevant in the course of the infection in vivo. Therefore, they demonstrate considerable biomedical potential as complements for classic therapy with antibiotics.

Evaluation of poly(amidoamine) dendrimers as potential carriers of iminodiacetic derivatives using solubility studies and 2D-NOESY NMR spectroscopy.

The interactions between dendrimers and different types of drugs are nowadays one of the most actively investigated areas of the pharmaceutical sciences. The interactions between dendrimers and drugs can be divided into: internal encapsulation, external electrostatic interaction, and covalent conjugation. In the present study, we investigated the potential of poly(amidoamine) (PAMAM) dendrimers for solubility of four iminodiacetic acid derivatives. We reported that PAMAM dendrimers contribute to significant solubility enhancement of iminodiacetic acid analogues. The nature of the dendrimer-drug complexes was investigated by (1)H NMR and 2D-NOESY spectroscopy. The (1)H NMR analysis proved that the water-soluble supramolecular structure of the complex was formed on the basis of ionic interactions between terminal amine groups of dendrimers and carboxyl groups of drug molecules, as well as internal encapsulation. The 2D-NOESY analysis revealed interactions between the primary amine groups of PAMAM dendrimers and the analogues of iminodiacetic acid. The results of solubility studies together with (1)H NMR and 2D-NOESY experiments suggest that the interactions between PAMAM dendrimers of generation 1-4 and derivatives of iminodiacetic acid are based on electrostatic interactions and internal encapsulation.Electronic supplementary material The online version of this article (doi:10.1007/s10867-012-9277-5) contains supplementary material, which is available to authorized users.

A validated 1H qNMR method for direct and simultaneous quantification of esculin, fraxin and (-)-epicatechin in Hippocastani cortex.

A fast and precise qNMR method was developed for quantification of major bioactive constituents in the bark of horse chestnut and dry extracts prepared thereof. The method was optimised using 600 MHz spectrometer, and the final acquisition parameters (90°-pulse, acquisition time - 3.0 s, relaxation delay - 27 s, number of transients - 16) allowed for performing of quantitative experiments in under 15 min. The contents of three analytes were determined using specific 1H resonances at δ7.45 ppm for esculin, δ5.00 ppm for fraxin, and δ5.94 ppm for (-)-epicatechin. The validation showed good precision (RSD < 1.5%) and accuracy (95-103%), and adequate sensitivity (LODs in the range of 3.3-5.9 µg) of the measurements. The determined levels in commercial samples of Hippocastani cortex were in the range of 25.89-38.94 mg/g dry weight (dw) of the bark for esculin, 12.58-17.13 mg/g dw for fraxin and 10.42-13.96 mg/g dw for (-)-epicatechin, and in the dry extracts prepared thereof 97.02-143.51 mg/g, 45.78-58.92 mg/g and 28.07-46.29 mg/g, respectively. The obtained results were cross-validated by a HPLC-PDA method with the use of a fused-core column, and no statistical differences were found between the results obtained by both methodologies, but with the advantage of higher precision of the qNMR assay. The relevant variability in quantitative composition of the commercial samples emphasise the need to introduce quality control studies in production of preparations containing horse chestnut bark and the developed method was proved suitable for this purpose.

Cationic carbosilane dendrimers-lipid membrane interactions.

The aim of this work was to study interactions between cationic carbosilane dendrimers (CBS) and lipid bilayers or monolayers. Two kinds of second generation carbosilane dendrimers were used: NN16 with Si-O bonds and BDBR0011 with Si-C bonds. The results show that cationic carbosilane dendrimers interact both with liposomes and lipid monolayers. Interactions were stronger for negatively charged membranes and high concentration of dendrimers. In liposomes interactions were studied by measuring fluorescence anisotropy changes of fluorescent labels incorporated into the bilayer. An increase in fluorescence anisotropy was observed for both fluorescent probes when dendrimers were added to lipids that means the decreased membrane fluidity. Both the hydrophobic and hydrophilic parts of liposome bilayers became more rigid. This may be due to dendrimers' incorporation into liposome bilayer. For higher concentrations of both dendrimers precipitation occurred in negatively charged liposomes. NN16 dendrimer interacted stronger with hydrophilic part of bilayers whereas BDBR0011 greatly modified the hydrophobic area. Monolayers method brought similar results. Both dendrimers influenced lipid monolayers and changed surface pressure. For negatively charged lipids the monitored parameter changed stronger than for uncharged DMPC lipids. Moreover, NN16 dendrimer interacted stronger than the BDBR0011.