Phylogenetic relationship of Glycyrrhiza lepidota, American licorice, in genus Glycyrrhiza based on rbcL sequences and chemical constituents

Two known saponins, licorice-saponin H2 and macedonoside A, were isolated from the stolons of Glycyrrhiza lepidota (American licorice) as major saponins. Since licorice-saponin H2 and macedonoside A are minor saponins isolated from the three glycyrrhizin-producing species (i.e. G. glabra, G. uralensis, G. inflata) and the three macedonoside C-producing species (i.e. G. macedonica, G. echinata, G. pallidiflora), respectively, the present study suggests that G. lepidota is an intermediate of both glycyrrhizin-producing and macedonoside C-producing species. The phylogenetic tree constructed from the nucleotide sequences of ribulose-1,5-bisphosphate carboxylase/oxygenase large subunit gene (rbcL) of these seven Glycyrrhiza plants indicated that G. lepidota was separated from the other six Glycyrrhiza species, and this phylogenetic relationship was in accordance with their saponin compositions.