Antidepressant-like effect of hydroalcoholic extract from barks of Rapanea ferruginea: Role of monoaminergic system and effect of its isolated compounds myrsinoic acid A and B.

Major Depressive Disorder (MDD) is a highly disabling condition and has been linked to increased inflammatory mediators. Hydroalcoholic extract from barks of Rapanea ferruginea (HEBRF) and the majoritary compounds-myrsinoic acid A (MAA) and B (MAB)-have been studied due to their anti-inflammatory potential, but there is no evidence about its antidepressant-like effects. This research investigated the HEBRF, MAA, and MAB antidepressant-like effect, besides the involvement of the monoaminergic system and MAO-A activity in the HEBRF antidepressant-like effect. HEBRF (50-300 mg/kg, p.o.), MAA (5-30 mg/kg, p.o.) or MAB (3-60 mg/kg, p.o.) were administrated to mice, and behavioral parameters were assessed using the tail suspension test (TST), splash test (ST) and open field test (OFT). The involvement of monoaminergic system in the HEBRF antidepressant-like effect was established through the pretreatment of mice with antagonists. The influence triggered by HEBRF in the monoamine oxidase A (MAO-A) activity was evaluated in the hippocampus (HIP) and prefrontal cortex (PFC) of mice. HEBRF (100-300 mg/kg) promoted antidepressant-like effect in the TST and augmented the total time of grooming in the ST, without compromising the locomotor activity. Pretreatment of mice with serotoninergic, dopaminergic, and noradrenergic antagonists, reversed the HEBRF antidepressant-like effect. Besides, HEBRF inhibited the MAO-A activity in the HIP and PFC. Moreover, MAA (5 mg/kg) and MAB (3 mg/kg) also promoted antidepressant-like and anti-anhedonic effects in mice. Data showed that monoaminergic system is involved in the HEBRF antidepressant-like effect, besides MAA and MAB possibly could be responsible for these pharmacological effects.

Avaliação psicofarmacológica do óleo essencial de Piper amplum / Psychopharmacology analysis of essential oil Piper amplum

Espécies do gênero Piper são utilizadas na medicina popular e carecem de validação farmacológica. Estudos científicos com a espécie Piper amplum são concentrados principalmente nos efeitos antimicrobianos e pouco se sabe sobre suas ações sobre o sistema nervoso central (SNC), apesar da planta ser utilizada de forma etnofarmacológica em processos neurológicos. Portanto, para avaliar os efeitos sobre o SNC, o óleo essencial obtido de Piper amplum (OEPA) (50, 100, 150 mg/kg, v.o.) foi administrado em camundongos fêmeas Swiss (25-30 g/ n=8-10 animais) e 60 minutos após os mesmos foram submetidos a testes de: depressão (teste do nado forçado, TNF), deambulação motora (campo aberto, TCA e Rotarod), convulsão e hipnose. Grupos controle-positivo (fármacos usados na terapêutica) e negativo (veículo no qual o OEPA foi dissolvido) foram utilizados nas mesmas condições experimentais. Os resultados demonstraram que o tratamento com OEPA não afetou a deambulação e atividade exploratória dos animais no TCA, assim como não afetou o sistema motor no Rotarod. Não foram detectados efeitos anticonvulsivante, hipnótico e ansiolítico do OEPA, entretanto, verificou-se atividade antidepressiva no TNF nas doses testadas. Diante dos efeitos do OEPA sobre o SNC, pode-se considerar o mesmo como alvo potencial para maiores estudos relacionados a atividade antidepressiva.(AU)

Species of the genus Piper used are in folk medicine and need pharmacological validation. Scientific studies with Piper amplum species are mainly concentrated on antimicrobial effects, little known is about their actions on the central nervous system (CNS), although the plant is ethnopharmacological used in neurological processes. Therefore, to evaluate the effects on the CNS, the essential oil obtained from Piper amplum (OEPA) (50, 100-150 mg/kg, p.o.) was administered in Swiss female mice (25-30 g/ n=8-10 animals) and 60 minutes after, the same were submitted to tests: depression forced swimming test, FST), motor ambulation (open field, OFT and Rotarod), seizure and hypnosis. Control-positive (drugs used in therapy) and negative (vehicle in which OEPA was dissolved) control groups were used under the same experimental conditions. The results showed that OEPA treatment did not affect the ambulation and exploratory activity of the animals in the OFT, and did not it affect the motor system in Rotarod. No anticonvulsive, hypnotic and anxiolytic effects of OEPA detected were, however, antidepressant activity in TNF at all doses tested. In view of the effects demonstrated by the OEPA on the CNS, it be can considered the same as a potential target for further studies related to antidepressant activity.(AU)