Objective: To explore the anxiolytic-like effect of extracts from a Chinese traditional herb

Moutan Cortex. Method: Eighty male Kunming mice were divided into eight groups:the vehicle-treated group (Control)

the diazepam-treated group (BZ

1 mg·kg-1

ip)

three phenolic component-treated groups (Px

10

20

40 mg·kg-1

ig) and three aqueous extract-treated groups (Wx

50

100

200 mg·kg-1

ig). Behavior of mice from each group in free exploratory paradigm (FEP)

open field test (OFT)

elevated plus maze (EPM)

elevated zero maze (EZM) and light/dark box (LDB) was recorded by sequence

with a less-than twenty-second interval. The following parameters were evaluated:percentage of time spent in the FEP novel compartment (Ntime%);percentage of number of units visited in the FEP novel area (Ncross%);percentage of number of rears in the FEP novel area (Nrear%);the total number of units visited in FEP (Cross);the total number of rears in FEP (Rear);percentage of time spent in the OFT central area (Ctime%);percentage of number of squares visited in the OFT central area (Ccross%);the total number of horizontal squares in OFT (Cross);the total number of rears in OFT (Rear);percentage of time spent in the EPM or EZM open arms (Otime%);percentage of number of entries into the EPM or EZM open arms (Oentries%);the total number of entries into the EPM or EZM open and closed arms (Entries);percentage of time exploring in the LDB light area (Ltime%);percentage of number of squares crossing in the LDB light area (Lcross%);percentage of rears in the LDB light area (Lrear%);the total number of transition in LDB (Transition);the total number of horizontal squares in LDB (Cross);the total number of rears in LDB (Rear). Result: Compared with control group

both 1 mg·kg-1 BZ and various doses of Px treatment obviously increased the percentage of exploratory and locomotor activity in FEP novel area

such as Ntime%

Ncross%

Nrear%;in OFT central area

such as Ctime%

Ccross%;in EPM and EZM open arms

such as Otime%

Oentries%;in LDB light area

such as Ltime%

Lcross%

Lrear%. However

only 200 mg·kg-1 Wx made an enhancement in OFT Ccross%

EZM Otime % and LDB Lrear%. Meanwhile

both BZ and various doses of Px and Wx showed no effect on the total locomotor and exploratory activity

such as Cross

Rear

Entries and Transition parameters in FEP

OFT

EPM

EZM or LDB. Conclusion: The phenolic components

such as paeonol and its analogues and metabolism

from Moutan Cortex

are the major active ingredients for the anxiolytic-like effect

and they may exhibit positive allosteric effect by targeting on GABAA receptor.