The genetic and chemical diversity in three original plants of licorice, Glycyrriza uralensis Fisch., Glycyrrhiza inflata Bat. and Glycyrrhiza glabra L.

Abstract

Licorice is one of the most frequently used Chinese herbs, mainly containing triterpenoids and flavonoids. Three original plants, Glycyrrhiza glabra L., Glycyrrhiza uralensis Fisch., and Glycyrrhiza inflata Bat., are defined as licorice in Chinese pharmacopeia. In this study, 40 G. uralensis samples (Group A), 60 G. glabra samples (Group B, C and D) and 40 G. inflata samples (Group E and F), were used as plant materials, the genetic diversity of samples were determined by gene sequencing technology and the chemotypic diversity were detected by HPLC. The chemotypic diversity analysis showed that contents of triterpenoids in G. glabra (isoglycyrrhizin: 2.483±0.0671 mg·g-1, glycyrrhizin: 34.660±0.8591 mg·g-1) were obviously higher than that in G. uralensis and G. inflata. However, the contents of flavonoids (liquiritin: 21.996±0.6396 mg·g-1, isoliquiritin: 4.556±0.1252 mg·g-1, liquiritigenin: 0.623±0.0200 mg·g-1, isoliquiritigenin: 0.281±0.008 mg·g-1) in G. uralensis were higher than that in G. glabra and G. inflata. And contents of triterpenoids and flavonoids were both lowest in G. inflata. The genetic diversity analysis showed that the psbA-trnH intergenic regions on chloroplast DNA sequences were same in the same species, and significantly different between any two species. These findings will lay a solid foundation for the identification and quality control of licorice. Furthermore,recently the activity of isoglycyrrhizin has attracted more and more attentions and researches. The HPLC method established in this paper for the simultaneous assay of isoglycyrrhizin and glycyrrhizin will be helpful for the screening of superior quality licorice with a high content of isoglycyrrhizin.