Extract of Yi Zhi Fang improves learning and memory behaviours of mice and its possible mechanisms.

The effects of Yi Zhi Fang extract (YZF) on learning and memory performances were investigated in mice using passive avoidance tasks. Oral administration of YZF improved learning and memory disorders induced by chemicals in both normal and senile mice. The acetylcholine (Ach) concentration, the muscarinic Ach receptors (M-R) and the monoamine oxidase B (MAO-B) activities were analysed by a radioimmunoassay, a radioligand receptor binding assay and UV spectrophotometry, respectively, using senile decapitated mice. The oral administration of YZF to the senile mice increased the M-R concentration, while the concentration of Ach and the activity of MAO-B decreased in senile mice brains. From these results it is evident that YZF promotes the function of the central cholinergic system and inhibits the activity of MAO-B in mice brains resulting in an enhancement of learning and memory.