Licorice, derived from the roots and rhizomes of Glycyrrhiza genus, is widely distributed all over the world. In China, three Glycyrrhiza species, G. uralensis, G. glabra, and G. inflata, are used as licorice without discrimination according to the 2015 edition of the Chinese Pharmacopoeia. Triterpenoid saponins, flavonoids and polysaccharides are considered as bioactive ingredients of licorice. The component properties, types and contents of these chemical compounds, vary significantly in different species and different licorice species have species-specific markers respectively, such as the contents of major flavonoids (liquiritin, liquilitigenin and isoliquiritin) in G. uralensis are obviously higher than in G. glabra and glycycoumarin only exists in G. uralensis. To some extent variation in active constituent could affect the therapeutic effects and safety of licorice, thus licorice used for medicinal purposes should be discriminated and chemically standardized according to those component properties in order to promote its reasonable application.
In this review, we describe differences of the types and contents of chemical composition among three licorice species. The result of this review is intended to provides the basis for the accurate identification and reasonable use of licorice.