Glycyrrhizin is a triterpenoid saponin isolated from liquorice, the dried unpeeled rhizome and root of the perennial herb Glycyrrhiza glabra (Leguminosae), a number of commercial varieties of which are cultivated. Much of liquorice is used in the form of a dried extract of the roots and stolons especially in confectionary and for flavouring, tobacco, beer etc. Owing to its sweet taste, liquorice has been long used in pharmacy to mask the bitter taste of drugs. It has been used in several formulations due to its surfactant, demulcent and mild expectorant properties. An important drug of Asian traditional medicine, liquorice, and its constituents, has been extensively investigated.

Liquorice extracts are reported with anti-inflammatory, corticosteroid-like and mineralocorticoid activities. These are used in the treatment of rheumatoid arthritis, Addison’s disease and various inflammatory conditions.

Other constituents of liquorice are triterpenoid saponins, glabranin A and B; glabrolide, isoglabrolide, glycyrrhetol; isoflavones; formononetin; glabrone; neolizuritun; hispaglabridin A and B and coumarins. The yellow colour of liquorice is due to flavonoids which are reported to have gastroprotective effects.

Glycyrrhizin is a mixture of potassium and calcium salts of glycyrrhizinic acid, which is the diglucopyranosiduronic acid of glycyrrhetenic acid which has a triterpenoid structure. Much of the activity reported for liquorice and its extracts has been attributed to glycyrrhetenic acid. It is found to inhibit enzymes that catalyse the conversion of prostaglandins and glucocorticoids into inactive metabolites, resulting in increased levels of prostaglandins and of hydrocortisone. This increased prostaglandin activity of liquorice and its constituents is used in the symptomatic treatment of peptic ulcer pain. A semi-synthetic derivative of glycyrrhetenic acid, the hemisuccinate carbenoxolone sodium, is widely prescribed for the treatment of gastric and duodenal ulcers.