Abstract: OBJECTIVE:To investigate the effects of active constituents extracted from Cortex Acanthopanacis Radicison improving the impaired memory in mice models.METHODS:The mice models of memory impairment were established using scopolamine.Ameliorating effects of the fractions and constituents on scopolamine-induced memory impairment in vivo were investigated using passive avoidance and Morris water-maze task tests,and their anti-acetylcholinesterase(AChE)and antioxidant activities in vitro examined.The isolation of constituents was performed by chromatographic methods and their structures were identified on the basis of instrumental analysis.RESULTS:Among the fractions tested,ethylacetate fraction exhibited the anti-AChE activity(25.83%±0.23%)properly and excellent 2,2-diphenyl-1-picrylhydrazyl(DPPH)radical and superoxide anion scavenging capacity(87.50%±0.83%and 60.22%±0.43%,respectively).However,the methylene chloride fraction was much more active than the ethylacetate fraction in the passive avoidance task test(167.5%increase of step-through latency time)and Morris water-maze task test(33.3%decrease of es-cape latency time).Four constituents,β-sitosterol,stigmasterol,sesamin,and hyperin were isolated from the methylene chloride fraction,among them,hyperin showed anti-acetylcholinesterase and anti-oxidant activities remarkably.Moreover,hyperin exerted a potent effect(146±38)s on memory improvement in terms of passive avoidance task test compared with the reference compound tacrine(162±43)s at a dose of 2.5 mg/kg.CONCLUSION:Hyperin,a flavonoid glucoside isolated from Cortex Acanthopanacis Radicis,inhibited AChE activity and potently ameliorated scopolamine-induced memory impairment,and its action may be partially mediated by the acetylcholine-enhancing cholinergic nervous system.

Key words: Cortex Acanthopanacis Radicis, Stigmas-terol, Sesamin, Hyperoside, Acetylcholinesterase