Abstract
In this study, methanolic crude extracts of Stephania japonica (Thunb.) Miers. (MESJ) whole plants were examined for possible antidepressant and sedative-hypnotic activities. Herein, the forced swimming test and tail suspension test were conducted to explore the antidepressant activity. In addition, the open field test and hole-board test were performed to evaluate the sedative-hypnotic activities. In the acute toxicity test, the MESJ ensured safety up to a dose of 2000 mg/kg, p.o. The experimental doses were 100 and 200 mg/kg p.o. In both the forced swimming test and tail suspension test, the extract significantly (p<0.01 and p<0.05) inhibited immobility time in a dose dependent manner compared to the control. These results (13.56-26.46% inhibition) indicate the mild antidepressant activity of MESJ compared to nortriptyline (60.4-64.6% inhibition). The open field test and hole-board test demonstrated the dose dependent significant (p<0.001, p<0.01 and p<0.05) and moderate sedative-hypnotic activities of the extract compared to diazepam. However, these activities were found to gradually decrease after 60 min in the open field test and must be considered as short-term activities, compared to diazepam. It can be claimed that the methanolic crude extract of Stephania japonica possesses mild antidepressant and moderate but short-term sedative-hypnotic activities.