The effects of the rhizome of Gastrodia elata Blume (Orchidaceae) (abb
reviated as GE) and its active constituents on learning and memory by
using the one-trial passive avoidance task were studied in rats. At th
e 1.0 g/kg dose administered for one week, the methanol extract of GE
significantly prolonged the shortened step-through latency induced by
scopolamine in the passive avoidance task. Furthermore, at the 50.0 mg
/kg dose administered for one week, the ethyl acetate and n-butanol fr
actions of the methanol extract prolonged the shortened step-through l
atency induced by scopolamine in rats. Gastrodin, isolated from the n-
butanol fraction of the methanol extract, and p-hydroxybenzyl alcohol,
isolated from the ethyl acetate fraction of the methanol extract, als
o significantly prolonged the shortened step-through latency induced b
y scopolamine on the passive avoidance task. These results suggested t
hat gastrodin and p-hydroxybenzyl alcohol may be the active constituen
ts of GE.