Simultaneous determination of glycyrrhizin, glycyrrhetic acid and glycyrrhetic acid mono-glucuronide in Shakuyaku-kanzo-to incubated with rat feces by semi-micro high-performance liquid chromatography

A method for semi-micro high-performance liquid chromatography (HPLC) has b een established for the simultaneous determination of glycyrrhizin (GL), gl ycyrrhetic acid (GA) and glycyrrhetic acid mono-glucuronide (GAMG) in incub ation mixtures of rat feces with Shakuyaku-kanzo-to decoction (combination of licorice root and peony root). The analysis could be accomplished within 20 min with a TSKgel ODS-80TsQA (150 X 2.0 min i.d.) column by linear grad ient elution using a mobile phase containing aqueous phosphoric acid and ac etonitrile at a flow rate of 0.2 ml . min(-1), a thermostatic oven at 25 de greesC, and detection at 254 nm. The detection limits of these compounds we re 0.1-0.85 pmol per injection (5 mul). The concentrations of GL and its me tabolites in the incubation mixture after continuous consumption of Shakuya ku-kanzo-to were significantly different compared with those of untreated c ontrol. GL-hydrolysis of rat feces was enhanced by pre-consumption of Shaku yaku-kanzo-to.