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.