Evaluation of the effect of Glycyrrhiza glabra linn root extract on spatial learning and passive avoidance response in rats

The roots and rhizomes of Glycyrrhiza glabra (Leguminosae) have been used in the traditional system of medicine for their antiinflammatory, antiulcer, expectorant and antimicrobial activities.They are also reported to have anxiolytic and antidepressant properties in mice.The present study was under taken to investigate the effect of Glycyrrhiza glabra on learning and memory in rats.Spatial learning T-maze and passive avoidance paradigm were employed to test learning and memory.Three doses of(100,200,300mg/ kg p.o) of the aqueous extract of Glycyrrhiza glabra were administered for 15 days in separate group of animals. The aqueous extract significantly improved spatial learning performance and retention of memory in rats. Furthermore 300mg/kg p.o of this extract significantly reversed the amnesia induced by scopalamine(0.5mg/kg i.p.)Anti oxidant property of Glycyrrhiza glabra may be contributing favourably to the memory enhancement effect.Since scopolamine induced amnesia was reversed by Glycyrrhiza glabra, it is possible that the beneficial effect on learning and memory was due to facilitation of cholinergic.