Antidepressant and Nootropic Activity of Aqueous Extract of Indigofera Tinctoria in Mice

Objective: The present study was undertaken to evaluate the antidepressant and nootropic potential of aqueous extract of Indigofera tinctoria (ITAE). Methods: Antidepressant activity of ITAE was evaluated in mice by using the forced swim test (FST), tail suspension test tail suspension test and tetrabenazine induced catalepsy and ptosis models at doses of 250 and 500 mg/kg orally. Nootropic activity was assessed using elevated plus maze (EPM) Morris water maze. Imipramine (25 mg/kg) and Piracetam (300 mg/kg) were used as standard drugs for antidepressant and nootropic activity respectively. Antioxidant assays like DPPH and TBARS was also carried out support the antidepressant and nootropic activity. Results: Pre-treatment with ITAE showed significant dose dependent reduction in immobility time displayed in both, FST and TST, when compared to that of vehicle.(P<0.05). Also, significant reduction in tetrabenazine induced catalepsy and ptosis was observed. Moreover ITAE showed dose dependent cognitive enhancing activity in MWM and EPM. ITAE exhibited IC50 value of 17.39 μg/ ml in DPPH assay and 398. 71 μgm/ ml in TBARS assay. Conclusion: ITAE exhibits significant antidepressant and nootropic activities at the dose of 250 and 500 mg/ kg which are comparable to imipramine and piracetam respectively which could be attributed to its effect on neurotransmitters and antioxidant activity respectively.