Structural features and in vivo antitussive activity of the water extracted polymer from Glycyrrhiza glabra

Antitussive drugs are amongst the most widely used medications worldwide; however no new class of drugs has been introduced into the market for many years. Herein, we have analyzed the water-extracted polymeric fraction (WE) of Glycyrrhiza glabra. This arabinogalactan protein enriched fraction, ≥85% of which gets precipitated with Yariv reagent, consisted mainly of 3- and 3,6-linked galactopyranosyl, and 5- and 3,5-linked arabinofuranosyl residues. Peroral administration of this polymer in a dose of 50 mg/kg body weight decreases the number of citric acid induced cough efforts in guinea pigs more effectively than codeine. It does not induce significant change in the values of specific airway resistance or provoked any observable adverse effects.