Effects of the mulberry leaf extract on depression-like behavior in mice / 国际药学研究杂志

ABSTRACT

Objective: To investigate the antidepressant effect and mechanism of the extract of mulberry leaf(EML). Methods: Male BALB/c mice were randomly assigned to receive EML(100, 200 and 400 mg/kg)or vehicle for 7 days or single administration by intragastric(ig)route. The effect of EML on spontaneous activity in mice was evaluated using the open field test. The anti-depressant activity of EML was evaluated using the tail suspension test and forced swimming test. After single ig administration of EML (100, 200 and 400 mg/kg), the effects of EML on the function central monoaminergic nervous system were evaluated using the 5-hydroxy-L-tryptophan(5-HTP)induced head-twitch test, yohimbine toxicity potentiation test and reserpine test in mice. Results: In the behavioral despair model, the continuous administration of EML(100 mg/kg)for 7 days significantly reduced the immobility time in the tail suspension test and forced swimming test. Compared with the vehicle group, the inhibitory rates of immobility time were 35.5% and 41%(P<0.05, P<0.01)in the tail suspension test and forced swimming test, respectively. The single treatment with EML(400 mg/kg)also significantly reduced the immobility time in the tail suspension and forced swimming test, and the inhibitory rates of immobility time were 29.1% and 35.3%, respectively(P<0.05). The results of spontaneous activity test showed that EML had no excitatory or inhibitory effect on the central nervous system in mice. In the 5-HTP induced head-twitch test in mice, the single treatment with EML(100 mg/kg)significantly increased the number of head-twitches in mice. In the yohimbine toxicity potentiation test, the single treatment with EML(100, 200 and 400 mg/kg)had no significant effect on the mortality rate in yohimbin-treated mice. In the reserpine test, compared with the model group, the single treatment with EML(400 mg/kg)antagonized reserpine induced ptosis (P<0.05)and had no significant effect on the decrease in rectal temperature and akinesia. Conclusion: EML showed antidepressant effect, and the action mechanism was likely related to the enhancement of the function of serotonergic nervous system.