Field Survey of Glycyrrhiza Plants in Central Asia (5). Chemical Characterization of G. bucharica Collected in Tajikistan

One triterpene and five triterpene glycosides, including four new compounds, have been identified in the underground parts of Glycyrrhiza bucharica, which was shown to be closely related to Glycyrrhizin-producing Glycyrrhiza species, G. uralensis, G. glabra and G. inflata, based on their chloroplast rbcL sequences. Two known compounds were identified squasapogenol and macedonoside C. The structures of four new compounds, bucharosides A, B, C, and D, were determined to be 3-O-alpha-L-rhamnopyranosyl-(1 -> 2)-beta-D-glucuronopyranosyl-(1 -> 2)-beta-D-glucuronopyranosyl-22-O-alpha-L-rhamnopyranosyl-squasapogenol, 3-O-alpha-L-rhamnopyranosyl-(1 -> 2)-beta-D-glucuronopyranosyl-(1 -> 2)-beta-D-glucuronopyranosyl-macedonic acid, 3-O-alpha-L-rhamnopyranosyl-(1 -> 2)-beta-D-glucuronopyranosyl-(1 -> 2)-beta-D-glucuronopyranosyl-squasapogenol, and 22-O-alpha-L-rhamnopyranosyl squasapogenol, respectively. Contents of these triterpene glycosides were less than 0.5% of dry weight, and no main saponin, like glycyrrhizin or macedonoside C found in other Glycyrrhiza species, was found in the underground parts of G. bucharica.