In the paper described comparative characteristic of polysaccharide complexes rough cornflower (Centaurea scabiosa L.) and lozhnopyatnistogo cornflower (Centaurea pseudomaculosа Dobrocz.). Was proposed the technique of sequential selection of water-soluble polysaccharides and pectins from the above-ground parts of the research objects. The content of water-soluble polysaccharides from the above-ground part of C. scabiosa is 2,8 times more (2,7 ± 0,3%, n = 3) than in C. pseudomaculosа (0,97 ± 0,50%, n = 3), pectins from the above-ground part of C. scabiosa is 2 times more (7,6 ± 0,4%, n = 3), than in C. pseudomaculosа (3,9 ± 0,3%, n = 3). The main monomer units of the polysaccharide complexes C. scabiosa and C. pseudomaculosa are D-galacturonic acid, L-rhamnose, D-xylose, D-mannose, D-galactose and D-glucose. From water-soluble polysaccharides of perspective C. scabiosa was isolated by ion exchange chromatography three fractions of polysaccharides (molecular weights of 667, 722 and 1027 kDa), which contain D-galacturonic acid, L-rhamnose, D-xylose, D-galactose and D-glucose.

As a result of investigation of antioxidant activity of the extracts from the aerial part of Centaurea jacea L. and Centaurea a pseudomaculosa Dobrocz.was established the evident antioxidant activity of the extract Centaurea jacea L. obtained with the use of 70% ethanol. Division of active extract into the fractions is not rational as this is not lead to increasing of antioxidant activity. Degree of the evidence of antioxidant properties is correlating with as flavonoids, as hydroxycinnamic acids content.

For the first time from the aerial parts of the rough cornflower ( Centaurea scabiosa L.) isolated and identified using GC-mass spectrometry of carboxylic acid esters: ethyl esters of palmitic and octadecenoic acids and palmitin (1 - (hydroxymethyl) -1,2-hexadecanoic acid ester etandiolovy), not previously described for this species.

The quantitative determination of flavonoids in the above-ground 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 aluminium chloride in hydrochloric acid. Depending on the site of plant collection, the quantitative content of flavonoids in the aboveground part of greater knapweed varied within 1.3 - 2.0% (as recalculated for rutin). The random error of measurement did not exceed 3% at а confidence probability of 0.95. The systematical error of the proposed method did not exceed the error of determination. The dynamics of accumulation of flavonoids in above-ground part of greater knapweed during vegetative period in 2006 has been traced for the plants growing in the Tomsk and Kemerovo regions. The maximum content of flavonoids (1.70 ± 0.04% recalculated for rutin) was observed in the stage of full blossom, which is therefore the optimum period for collecting the above-ground part of 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 above-ground part of greater knapweed (1.70 ± 0.04%).

We have studied the composition of biologically active substances in an aqueous extract from common coach grass (Eletrigia repens) and identified compounds belonging to the following chemical groups: coumarins, iridoids, saponins, slimes, polysaccharides (including inulin), ascorbic acid, β-carotene, flavonoids (rutin, hyperoside, bajcaleine), phenolcarboxylic acids (chlorogenic acid,p-hydroxycinnamic acid) and tannins. The influence of an ointment based on the extract fromEletrigia repens on some parameters of lipid peroxidation under conditions of experimental allergic contact dermatitis has been studied. It is established that the ointment produces normalization of the parameters of lipid peroxidation (diene conjugates, malonic dialdehyde, catalase) in the blood plasma of experimental animals.