The effects of Valeriana officinalis L. hydro-alcoholic extract on depression like behavior in ovalbumin sensitized rats

BACKGROUND: Neuroimmune factors have been considered as contributors to the pathogenesis of depression. Beside other therapeutic effects, Valeriana officinalis L., have been suggested to have anti-inflammatory effects. In the present study, the effects of V. officinalis L. hydro alcoholic extract was investigated on depression like behavior in ovalbumin sensitized rats. MATERIALS AND METHODS: A total of 50 Wistar rats were divided into five groups: Group 1 (control group) received saline instead of Valeriana officinalis L. extract. The animals in group 2 (sensitized) were treated by saline instead of the extract and were sensitized using the ovalbumin. Groups 3-5 (Sent - Ext 50), (Sent - Ext 100) and (Sent - Ext 200) were treated by 50, 100 and 200 mg/kg of V. officinalis L. hydro-alcoholic extract respectively, during the sensitization protocol. Forced swimming test was performed for all groups and immobility time was recorded. Finally, the animals were placed in the open-field apparatus and the crossing number on peripheral and central areas was observed. RESULTS: The immobility time in the sensitized group was higher than that in the control group (P < 0.01). The animals in Sent-Ext 100 and Sent-Ext 200 groups had lower immobility times in comparison with sensitized group (P < 0.05 and P < 0.01). In the open field test, the crossed number in peripheral by the sensitized group was higher than that of the control one (P < 0.01) while, the animals of Sent-Ext 50, Sent-Ext 100 and Sent-Ext 200 groups had lower crossing number in peripheral compared with the sensitized group (P < 0.05 and P < 0.01 respectively). Furthermore, in the sensitized group, the central crossing number was lower than that of the control group (P < 0.001). In the animals treated by 200 mg/kg of the extract, the central crossing number was higher than that of the sensitized group (P < 0. 05). CONCLUSIONS: The results of the present study showed that the hydro-alcoholic extract of V. officinalis prevents depression like behavior in ovalbumin sensitized rats. These results support the traditional belief on the about beneficial effects of V. officinalis in the nervous system. Moreover, further investigations are required in order to better understand this protective effect.