Liquorice, Glycyrrhiza glabra L.—Composition, uses and analysis

The liquorice plant (Glycyrrhiza glabra L., formerly Liquiritae officinalis Moench) has been used by physicians and herbalists since the earliest of times. Many of the early claims for the effectiveness of liquorice extracts, decoctions and potions have been shown by modern science to be credible, a root component (glycyrrhizin) being generally regarded as the major biologically-active principle. Liquorice extracts (in pharmacy called succus liquiritae) are currently used mainly in the tobacco, pharmaceutical and confectionery industries; because such extracts contain glycyrrhizin there is a need for accurate methods for its estimation, in both crude isolates and finished products. The purpose of this review is to briefly describe the background to current interests in liquorice, to indicate the origins and usage of liquorice extracts and to discuss the composition of liquorice, with particular emphasis on glycyrrhizin. Current methods for the analysis of glycyrrhizin will be considered and the levels found in liquorice roots, extracts and a range of products indicated. Brief mention will also be made of human exposure levels and the possible risk to human health as a result of consuming liquorice-based products.