Behavioural and neuroendocrine effects of aqueous extract of Boerhaavia diffusa Linn. in mice using tail suspension and forced swim tests--a preliminary study.

The present study was done to evaluate the effect of aqueous extract of B. diffusa on depression in mice using behavioral models such as tail suspension test (TST) and forced swim test (FST). The extract (50, 100 and 200 mg/kg, po) was administered for 14 successive days to Swiss young albino mice. On 14th day, 60 min after administration, mice were subjected to TST and FST. The administration of aqueous extract of B. diffusa (50, 100 and 200 mg/kg, po) significantly decreased immobility period in both TST and FST, indicating significant antidepressant-like activity. The lowest dose (50 mg/kg) of the extract decreased the immobility period most significantly in FST, showing most potent antidepressant-like action. The efficacy of the extract (50 mg/kg) was comparable to fluoxetine (20 mg/kg). The extract did not show any significant effect on locomotor activity. The extract showed significant monoamine oxidase -A inhibitory activity. There was no significant effect of the extract on plasma corticosterone levels. Prazosin (alpha1-adrenoceptor antagonist), sulpiride (selective D2-receptor antagonist), baclofen (GABA(B) agonist), and p-CPA (tryptophan hydroxylase inhibitor) significantly attenuated the extract-induced antidepressant-like effect, when tested in TST. The extract might produce antidepressant-like effect by interaction with alpha1-adrenoceptors, dopamine-D2 receptors, serotonergic, and GABA(B) receptors. Thus, aqueous extract of B. diffusa showed significant antidepressant-like activity in mice probably through involvement of monoaminergic and GABAergic systems.