318 



SUBTERRANEAN ORGANS 



glycyrrhizinic acid, a colourless, crystalline acid, slightly soluble 

 in water, but imparting a sweet taste to it in a dilution of 1 in 20,000 ; 

 it is not a glucoside as was formerly supposed, since it yields on 

 hydrolysis glycyrrhetinic acid and glycuronic acid, but no sugar. 

 Liquorice root contains about 5 to 7 per cent, of it. The drug also 

 contains glucose (14 per cent.), sucrose (2-5 per cent.), starch (29 per 

 cent.), an acrid bitter principle, proteids, asparagin, fat, and resin. 

 It yields from 3 to 4 per cent, of ash, and from 15 to 27 per cent, of 

 aqueous extract dried at 100 (official minimum 20 per cent.). 



Many other plants are remarkable for their sweet taste, but the presence of 

 glycyrrhizin has been definitely proved only in Periandra dulcis, Martius (N.O. 

 Leguminosce, Brazil), Pradosia lalescens, Radlkofer (Monesia bark, N.O. Sapo- 



tacece, Brazil). The root of Abrus preca- 

 torius, Linn6 (Indian liquorice, N.O. Legu- 

 minosce}, Trifolium alpinum, Linne (mountain 

 liquorice, N.O. Leguminosce, Europe), Astra- 

 galus Glycyphyllos, Linne (N.O. Leguminosce), 

 Poly podium vulgare, Linne (N.O. Polypodi- 

 acece), Myrrhis odorata, Scopoli (N.O. Um- 

 belliferce), Ononis spinosa, Linne (N.O. 

 Leguminosce), &c., contain sweet principles, 

 possibly glycyrrhizin. The leaves of Eu- 

 patorium Rebaudianum (N.O. Compositce), 

 contain eupatorin, and rebaudin said to be 

 180 times as sweet as sugar. 



According to Robert eupatorin is a 

 neutral and rebaudin an acid saponin 

 (compare p. 254). Glycyrrhizin also belongs 

 to the saponin s ; it has no haemolytic action, 

 but its decomposition product, glycyrrhe- 

 tinic acid, has ; Robert considers that this explains the value of liquorice as 

 a remedy for coughs. 



Uses. Liquorice root is a demulcent and expectorant ; the liquid 

 extract is frequently employed to mask the taste of nauseous 

 medicines. 



Varieties. Russian Liquorice Root. Very large quantities of 

 liquorice root are collected in southern Russia, where the plant grows 

 wild on the banks of the Volga and other rivers, needing no cultivation. 

 The plant that yields this root is G. glandulifera, Waldstein and 

 Kitaibel. Instead of producing numerous runners this plant forms 

 a large rootstock, from which long perennial roots are given off. 

 These are usually freed from the purplish brown cork by scraping. 



Nearly all the Russian liquorice root that reaches this country 

 has been peeled, and presents therefore a smooth yellow exterior, to 

 which loose fibres are attached, the larger pieces being often longitu- 

 dinally split. It attains a much larger size than the Spanish, the 



FIG. 162. Russian Liquorice 

 root. Transverse section. Mag- 

 nified 1| diam. (Berg.) 



