Field Survey of Glycyrrhiza Plants in Central Asia (4). Characterization of G. glabra and G. bucharica Collected in Tajikistan.

The characteristics of 2 Glycyrrhiza plants, G. glabra and G. bucharica (=Meristotropis bucharica), were investigated in Tajikistan. The glycyrrhizin content in the underground parts of G. glabra varied from 2.56 to 9.29% of the dry weight, and the content of glabridin, a species-specific flavonoid of G. glabra, varied from 0.09 to 0.92% of the dry weight. Seeds of G. glabra plants from Tajikistan were cultivated for 3 years in Japan, and the glycyrrhizin content of the harvested roots ranged from 0.75 to 1.82% of the dry weight. In addition, HPLC analysis of leaf extracts indicated that the G. glabra plants collected in Tajikistan could be divided into various types, according to the flavonoid contents of the leaves. The endemic G. bucharica was also collected. A phylogenetic tree of rbcL nucleotide sequences from various Glycyrrhiza plants indicated that G. bucharica was closely related to the three glycyrrhizin-producing Glycyrrhiza spp. (G. uralensis, G. inflata, and G. glabra), even though G. bucharica does not produce glycyrrhizin.