Effects of Marapuama in the chronic mild stress model: Further indication of antidepressant properties

Ptychopetalum olacoides Bentham (PO) (Olacaceae), known as Marapuama, is regarded as a “nerve tonic” in the Amazon. Traditional uses include states of lassitude with noticeable lack of desire/motivation, and to manage particularly stressful (physical and/or psychological) circumstances. Suggestive of antidepressant activity, we have established that a specific PO ethanol extract (POEE) significantly decreases immobility in the tail suspension and forced swimming tests. The aim of this study was to verify the effects of POEE in the unpredictable chronic mild stress (UCMS) depression model in mice, given the construct and face values of the UCMS as an experimental model of depression and the traditional use of this species. Over 6 weeks BALB/c mice were subjected to the UCMS protocol. The effects of POEE (50, 100, 300 mg/kg, p.o.) and imipramine (20 mg/kg, i.p.) were evaluated in relation to coat state, splash-test grooming, and corticosterone levels. The coat state degradation, decreased grooming and increased serum corticosterone induced by UCMS were prevented by POEE and imipramine treatments. In addition to supporting traditional claims and previously reported antidepressant properties for POEE, this study shows that POEE prevents stress-induced HPA hyperactivity.