Quantitative determination of constituents in various licorice roots by means of high performance liquid chromatography

During the course of our studies on the chemical constituents of botanically identified Chinese licorice roots of various origins, we have identified 15 kinds of saponins and 49 kinds of flavonoids (including flavonoid glycosides). With these chemical constituents at hand, we have carried out the chemical evaluation studies of licorice roots available in Japan by means of high performance liquid chromatography (HPLC). In the HPLC analysis using an ODS reversed-phase column, a combination of 1% aqueous acetic acid and acetonitrile was used as the mobile phase in a gradient solvent system, and the eluate was monitored with UV absorption at 254 nm (for saponins with a diene or a conjugated carbonyl moiety, liquiritin, and liquiritin apioside) or at 350 nm (for other flavonoid constituents). By our analytical method described here, quantitative analyses of saponin and flavonoid constituents were effected simultaneously. We have found an interesting piece of information concerning the origin of parent plants and their characteristic constituents such as saponins and flavonoids.