THE MAIN GOAL OF RESEARCH

Within the field of pharmacologically active polymers the area of immunomodulatory poly[3-(3,4-dihydroxyphenyl)glyceric acid] polyether seems rather new and attractive. Preliminary studies on the polysaccharide composition of several plants belonging to Caucasus flora and using in folk medicine showed that, unlike the polysaccharides from other plants, the crude polysaccharides from S. asperum and S. caucasicum possess a high anticomplementary activity.

In order to determine the chemical nature of active components, both polysaccharide preparations were fractionated by ultrafiltration on membrane filters. As a result the retaining of main anticomplementary activity in the fractions with molecular masses exceeding 1 MDa was observed. This fractionation procedure allowed to remove most ballast polysaccharides and to obtain water-soluble high-molecular (> 1000 kDa) preparations from S. asperum and S. caucasicum, which contained minor amounts of carbohydrates (25.7% and 26.9%, respectively). The absorption maxima at 213, 237, 282(shoulder) and 286 nm in water were observed in UV spectra of both preparations. According to the data of IR, ¹³C and ¹H NMR, APT and 2D heteronuclear ¹³C/¹H HSQC spectra and 1D-NOE experiment, one and the same poly[oxy-1-carboxy-2-(3,4-dihydroxyphenyl)ethylene] is the main structural element of both high-molecular water-soluble preparations isolated from the roots of S. asperum and S. caucasicum. Such biopolymer is, hitherto, not known and has been identified for the first time. This compound is a representative of a new class of natural polyethers with a residue of 3-(3,4-dihydroxyphenyl)glyceric acid as the repeating unit.

Besides high anticomplementary activity, poly[3-(3,4-dihydroxyphenyl)glyceric acid] from the roots of S. asperum demonstrated antioxidant, antilipoperoxidant, and antiinflammatory properties.

Aqueous extracts from Symphytum species are used in traditional medicine as anti-inflammatory and wound-healing agents. The water-soluble caffeic acid-derived polymer from these plants may participate in the global activity of the plant extract. Because of its strong antilipoperoxidant activity, it may partly prevent both LDL oxidation and formaton of by-products resulting from lipid lipoperoxidation, and therefore, it may have a beneficial effect in the prevention of atherosclerosis and cardiovascular diseases and also, for patients suffering from predisposing inflammatory conditions such as ulcerative colitis and Crohn’s disease. On the basis of its high antioxidant and antilipoperoxidant activity, the Symphytum new polymer might have chemopreventive potential. Besides, it was shown that above-mentioned polymers from the roots of S. asperum and S. caucasicum can modulate B-chronic lymphocytic leucaemia (B-CLL) apoptosis and cell cycle progression, therefore these substances can be proposed for further investigations as prospective tumour modulating preparations.