Characterization and pharmacodynamic properties of Arnica montana complex.

A dark brown polymeric complex was isolated from flowering parts of medicinal plant Arnica montana L. by hot alkaline extraction followed by neutralization and multi-step extractions with organic solvents. It was recovered in 5.7% yield, on GPC showed two peaks of molecular mass of 9 and 3.5kDa. The compositional analyses of Arnica complex revealed the presence of carbohydrates (26%), uronic acids (12%), phenolics (1.25mM or 213mg of GAE/1g), and low protein content (∼1%). The carbohydrate moiety was rich mainly in rhamnogalacturonan and arabinogalactan. The antitussive tests showed the reduction of the cough efforts by Arnica complex, however, its total antitussive effect was lower compared with that of codeine, the strongest antitussive agent. The bronchodilatory activity of Arnica complex was similar to salbutamol, a classic antiasthmatic drug, and was confirmed by significantly decreased values of specific airways resistance in vivo and by considerably attenuated the amplitude of acetylcholine and histamine-induced contractions in vitro. Arnica complex did not show any cytotoxic effect on mouse fibroblast cultures and human lung cells, up to the dose of 500µg/mL.

Thrombin inhibitory activity of some polyphenolic compounds.

Thrombin, also known as an active plasma coagulation factor II, belongs to the family of serine proteases and plays a crucial role in blood coagulation process. The process of thrombin generation is the central event of the hemostatic process and regulates blood coagulant activity. For this reason, thrombin inhibition is key to successful novel antithrombotic pharmacotherapy. The aim of our present study was to examine the effects of the well-known polyphenolic compounds on the activity of thrombin, by characterization of its interaction with selected polyphenols using different biochemical methods and biosensor BIAcore analyses. Only six compounds, cyanidin, quercetin, silybin, cyanin, (+)-catechin and (-)-epicatechin, of all examined in this study polyphenols caused the inhibition of thrombin amidolytic activity. But only three of the six compounds (cyanidin, quercetin and silybin) changed thrombin proteolytic activity. BIAcore analyses demonstrated that cyanidin and quercetin caused a strong response in the interaction with immobilized thrombin, while cyanin and (-)-epicatechin induced a low response. Lineweaver-Burk curves show that used polyphenol aglycones act as competitive thrombin inhibitors. Our results suggest that polyphenolic compounds might be potential structural bases and source to find and project nature-based, safe, orally bioavailable direct thrombin inhibitors.

Characterization and biological activity of Solidago canadensis complex.

Polyphenolic-polysaccharide-protein complex has been isolated from flowers of Solidago canadensis L. by hot alkaline extraction procedure. Compositional analyses of S canadensis complex revealed the presence of carbohydrates (43 wt%), protein (27 wt%), phenolics (12 wt%), uronic acids (10 wt%) and inorganic material (8 wt%). The carbohydrate part was rich in neutral sugars (81 wt%) while uronids were determined in lower amount (19 wt%). Monosaccharide analysis of carbohydrate part revealed the presence of five main sugar components, i.e. rhamnose (~23 wt%), arabinose (~20 wt%), uronic acids (~19 wt%), galactose (~17 wt%) and glucose (~14 wt%), and indicated thus the presence of rhamnogalacturonan and arabinogalactan in S. canadensis complex. HPLC analysis of complex showed one single peak of molecule mass at 11.2 kDa. Antitussive activity tests, performed in three doses of Solidago complex, showed the reduction of the number of cough efforts in the dose-dependent manner. Higher doses (50 and 75 mg/kg b.w.) were shown to be by 15 and 20% more effective than that of lower one (25mg/kg b.w.). However, the antitussive effect of the highest dose (75 mg/kg b.w.) was by 10% lower in comparison with that of codeine, the strongest antitussive agent. Besides, the highest dose of the complex (75 mg/kg b.w.) significantly decreased values of specific airways resistance and their effect remained longer as that of salbutamol, a representative of classic antiasthmatic drugs.

Antitussive and bronchodilatory effects of Lythrum salicaria polysaccharide-polyphenolic conjugate.

A high molecular mass polysaccharide-polyphenolic conjugate has been isolated from flowering parts of Lythrum salicaria by hot alkaline extraction. Its chemical analysis revealed 74% of carbohydrates and 17% of phenolics. Compositional analysis of carbohydrate part showed a high GalA content (49%), Rha (25%), Gal (13%) and Ara (9%) residues, and indicated thus rhamnogalacturonan associated with arabinogalactan in Lythrum conjugate. Antitussive activity tests, performed in three doses of Lythrum conjugate - 25, 50 and 75 mg/kg of animal body weight, showed the reduction of the number of cough efforts even 5h after administration. However, their antitussive effects were lower in comparison with that of codeine, the strongest narcotic antitussive agent. The tests evaluating the influence of different doses on airways smooth muscle reactivity revealed more significant effect of Lythrum conjugate in comparison with that of salbutamol, a commercial bronchodilator used in a clinical practice. Measurements of specific airway resistance pointed at both, the dose-dependent bronchodilatory activity and possible participation of bronchodilation on antitussive effect of Lythrum conjugate. This study represents the first sight into pharmacodynamic properties of Lythrum polysaccharide-polyphenolic glycoconjugate.

Effects of the extract from Conyza canadensis on human blood platelet aggregation.

The effects of different parts of extract from medicinal plant Conyza canadensis, used to control bleeding, on human blood platelet aggregation in vitro were investigated. Aqueous extract of Conyza c. from young or old plants, glycoconjugate part, polysaccharide part and aglycon part at the concentrations above 0.75 mg/ml strongly inhibited platelet aggregation induced by collagen (2 microg/ml) in dose-dependent manner. Polysaccharide part isolated from plant extract had the strongest inhibitory effect on aggregation stimulated by collagen and seems to be responsible for antiaggregatory properties.

The membrane-disrupting activity of alpha-aminoalkanephosphonic acids and their derivatives.

The influence of a series of acyclic and cyclic aminophosphonates on the physicochemical properties of model (planar lipid membranes-BLM) and biological (erythrocytes-RBC) membranes was studied. The results obtained were compared with the results of physiological tests performed on the aquatic plant Spirodela oligorrhiza. It was found that the inhibition of plant growth by the compounds studied correlated, although not very highly, with the observed changes in the properties of membranes used. It was also found that both the biological activity of aminophosphonates and their efficiency at modifying the physicochemical parameters of membranes depended on their structural features.