Nrf2 activators from Glycyrrhiza inflata and their hepatoprotective activities against CCl4-induced liver injury in mice.

Glycyrrhiza inflata (licorice) has been used to treat liver diseases for a long history. However, the bioactive compounds are still not clear. In this work, 77 compounds, including 9 new ones, were isolated from the EtOAc extract of the roots and rhizomes of G. inflata. The Nrf2 activation activities of all compounds were screened using ARE-luciferase reporter assay on HepG2C8 cells. The results indicated a number of chalcones were potent Nrf2 activators, including 11 (licochalcone A, 4.07-fold), 12 (licochalcone B, 5.17-fold), and 19 (echinatin, 4.09-fold). Further studies indicated that 11, 12 and 19 remarkably attenuated CCl4-induced acute liver injury in mice (10 or 50mg/kg, 7days, ig.). These compounds could be promising hepatoprotective natural agents.