Glabridin was isolated from the roots of Glycyrrhiza glabra and its effects on cognitive functions and cholinesterase activity were investigated in mice. Glabridin (1, 2 and 4 mg kg (-1), P. O.) and piracetam (400 mg kg (-1), i. p.), a clinically used nootropic agent, were administered daily for 3 successive days to different groups of mice. The higher doses (2 and 4 mg kg (-1), P. O.) of glabridin and piracetam significantly antagonized the amnesia induced by scopolamine (0.5 mg kg (-1), I. P.) in both the elevated plus maze test and passive avoidance test. Furthermore, glabridin (2 and 4 mg kg (-1), P. O.) and metrifonate (50 mg kg (-1), I. P.), used as a standard drug, both remarkably reduced the brain cholinesterase activity in mice compared to the control group. Therefore, glabridin appears to be a promising candidate for memory improvement and it will be worthwhile to explore the potential of glabridin in the management of Alzheimer patients.

Licochalcone A was isolated from the roots of Glycyrrhiza inflata and evaluated for its anti-inflammatory activity in xylene-induced mice ear edema and carrageenan-induced paw edema tests. At the same time, the inhibition of prostaglandin biosynthesis by licochalcone A was also studied in lipopolysaccharide (LPS)-induced mouse macrophage cells. At 5 mg/ ear, licochalcone A showed remarkable effects against acute inflammation induced by xylene, and at the doses of 2.5, 5, 10 mg/kg (p.o.), licochalcone A reduced significantly paw edema induced by carrageenan compared to the control at the fourth hour. Both COX-2 activity and expression were significantly inhibited by licochalcone A at all the test doses. Therefore, licochalcone A could be a useful compound for the development of new anti-inflammatory agents.