We characterized polysaccharide complexes from Centaurea scabiosa L. and Centaurea pseudomaculosа Dobrocz. We proposed the technique of sequential selection of water-soluble polysaccharides and pectin substances from the aerial parts of studied objects. We have discovered that the content of water-soluble polysaccharides in the aerial parts of C. scabiosa was 2.8 times higher (2.7 ± 0.3%, n = 3) than in C. pseudomaculosа (0.97 ± 0.50%, n = 3). The content of pectin substances in the aerial parts of C. scabiosa was 2 times higher (7.6 ± 0.4%, n = 3) than in C. pseudomaculosа (3.9 ± 0.3%, n = 3). The residues of D-galacturonic acid, L-rhamnose, D-xylose, D-mannose, D-glucose, and D-galactose are the monomeric units of polysaccharide complexes from C. scabiosa and C. pseudomaculosa. Using ion-exchange chromatography, three polysaccharide fractions (molecular weights 667, 722, and 1027 kDa), whose monomer units are D-galacturonic acid, L-rhamnose, D-galactose, D-xylose, and D-glucose were isolated from the water-soluble polysaccharides of C. scabiosa.

The composition of biologically active substances of aqueous extracts of couch grass was studied and the following groups of biologically active substances were identified: coumarins, iridoids, saponins, slimes, polysaccharides (including inulin), ascorbic acid and β-carotene, flavonoids (rutin, hyperoside, baicaleine) phenocarboxylic acids (chlorogenic and p-hydroxycinnamic acids), and tannins. The effects of couch grass extract in the form of a cream on several measures of lipid peroxidation in allergic contact dermatitis were studied in experimental conditions. Cream containing couch grass extract was found to have normalizing actions on measures of lipid peroxidation (diene conjugates, malondialdehyde, catalase) in the plasma of experimental animals.

Quantitative determination of flavonoids from the aerial part of greater knapweed ( Centaurea scabiosa L.) has been carried out by differential spectrophotometry in combination with a modified method of forming flavonoid complexes with aluminum chloride in HCl. Depending on the plant collection site, the quantitative content of flavonoids in the aerial part of greater knapweed varied within 1.3 – 2.0% (calculated as rutin). The random error of measurement did not exceed 3% at a confidence probability of 0.95. The systematic error of the proposed metohd did not exceed the error of determination. The accumulation dynamics of flavonoids in the aerial part of greater knapweed during the 2006 vegetative peroid have been tracked for plants growing in Tomsk and Kemerovo regions. The maximum content of flavonoids (1.70 ± 0.04% calculated as rutin) was observed in the stage of full flowering, which is therefore the optimum period for collecting the aerial part of the plants for the maximum yield of flavonoids. The maximum amount of flavonoids was accumulated in leaves (1.96 ± 0.04%), which is somewhat greater than the content of flavonoids in the entire aerial part of greater knapweed (1.70 ± 0.04%).

Previously [1] we described the preparation of crowberry (Empetrum nigrum) extract used in the anticonvulsant phytopreparation empetrin. The crowberry extract was obtained by treating the plant sprouts with boiling chloroform followed by purification of the concentrated infusion with acetone. The results of elemental analyses showed the presence of oxygen-containing compounds and the absence of nitrogen-containing components in empetrin. An analysis of the IR, 1 H and 13 C NMR, and mass spectra of the phytopreparation showed that the extract components include aliphatic higher esters, acids, alcohols, ketones, macrocyclic alkanes, triterpene compounds, and a considerable amount of paraffins [2 – 5]. In order to remove the paraffin fraction and other low-polarity components from the phytopreparation, we used extraction with pentane in a Sohxlet apparatus. Subsequent pharmacological tests using two commonly accepted methods (maximum electroshock and corazole “titration”) showed that the anticonvulsant activity is present in the pentane-insoluble residue. Separation of this residue into components presented a difficult experimental problem. As is known, titanium tetrachloride (TiCl 4 ) is capable of forming complexes with hydrophobic oxygen-containing compounds dissolved in alcohol, water, and water – alcohol mixtures [6, 7]. However, in using complexation for the isolation of high-molecular-weight heteroatomic compounds, it is necessary to take into account the retarding effect of the growing hydrocarbon fragment, which increases the hydrophobic properties and weakens the characteristic properties of a heteroatom in the functional group. In order to overcome the hydrophobicity barrier, we used complexation with titanium tetrachloride in hydrocarbon solvents [8] because molecules of titanium tetrachloride (possessing a zero dipole moment) exhibit unlimited solubility in such solvents. It is especially important that the molecular polarizability of TiCl 4 is comparable with that of hydrocarbons. Titanium tetrachloride exhibits a high donor – acceptor capacity with respect to oxygen-containing ligands, which can be readily recovered from the titanium chloride complexes. Taking into account the hydrophobic character of empetrin components (insoluble in pentane), we studied the possibility of separating the oxygen-containing substances in crowberry extract by the method of fractional complexation with titanium tetrachloride in a hydrocarbon medium.

Four phenolic components are isolated from the CHCl3extract ofEmpetrum nigrumL. Three of them are known from this plant. The fourth (6,8-dimethylpinocembrine) is isolated from crowberry for the first time. The previously proposed structure for 2'-methoxy-4'-hydroxy- α,β-dihydrochalcone is confirmed by x-ray structure analysis

Continuing a study of the chemical composition of the black crowberry Empetrum ni~ L. [i], we have investigated the flavonoids of the plant. For their isolation, the air-dry comminuted epigeal parts (leafy stems) of the crowberry were treated with chloroform to eliminate substances of lipophilic nature and were then extracted exhaustively with boiling 70% ethanol. The aqueous ethanolic extracts were concentrated in vacuum to an aqueous residue, which was purified with chloroform, and the flavonoids were extracted with ethyl acetate. The ethyl acetate fraction was separated on a column of polyamide sorbent in a ratio of 1:30. On elution with water and with aqueous alcohol (containing from i0 to 96% of ethanol), five flavonoid substances (I-V) were isolated.