Antidepressant-Like Potentials of Vernonia Amygdalina (Asteraceae) in Laboratory Mice and the Implication of the Monoaminergic Systems

Vernonia amygdalina commonly called bitter leaf, belongs to the family Astaraceae, and has been reported to be used locally in the treatment of psychiatric challenges. However, dearth work has been reported on anxiety and no work has been reported on depression. This study was therefore designed to investigate the antidepressant activities of Vernonia amygdalina and its probable mechanism of activities in mice. The antidepressant-like potentials of VA (50-200mg/kg) was explored in Forced Swimming Test (FST), Tail Suspension Test (TST), reserpine-induced models and Open Field Test (OFT). Mice were pre-treated with graded doses VA (50-200 mg/kg) and imipramine (60mg/kg). And, also mice were pre-treated with monoamine receptor blockers: metergoline (5-HT2), prazosin (alpha-1- adrenoceptor) and sulpiride (D2) before VA (100mg/kg) was administered to elucidate the mechanisms involved in it antidepressant-like effects using the TST. Vernonia amygdalina (100mg/kg and 200mg/kg) were found to be significantly increase mobility as when compared with control in FST and TST model. 100mg/kg and 200 mg/kg of VA reduced the ptosis in reserpine-induced depression and 200 mg/kg of VA was able to increase the temperature in mice in reserpine-induced depression. VA was seen to be mediated through alpha- 1-adrenergic receptor, dopamine D2 receptor and 5-HT2 receptor as there was significant increase immobility when compared to 100 mg/kg of VA. This study showed that Vernonia maygdalina may possess antidepressantlike effects in FST, TST and reserpine-induced depression models which may be mediated through serotonergic, nor-adrenergic and dopaminergic system.