Abstract:
Ethnopharmacological relevance: Xylopia aethiopica has been used traditionally to treat some central
nervous system disorders including epilepsy.
Aim of the study: Despite the central analgesic and sedative effects, there is little evidence for its tra-
ditional use for CNS disorders. This study thus assessed the antidepressant potential of Xylopia aethiopica
ethanolic fruit extract (XAE).
Material and methods: Antidepressant effect was assessed in the forced swim test (FST) and tail sus-
pension test (TST) models in mice. The role of monoamines in the antidepressant effects of XAE was
evaluated by selective depletion of serotonin and noradrenaline, whereas involvement of NMDA/nitric
oxide was assessed with NMDA receptor co-modulators; D-serine and D-cycloserine and NOS inhibitor, L-
NAME.
Results: Xylopia aethiopica (30, 100, 300 mg kg 1) dose dependently reduced immobility in both FST and
TST. The reduced immobility was reversed after 5-hydroxytryptamine (5-HT) depletion with tryptophan
hydroxylase inhibitor—p-chlorophenylalanine (pCPA) and after monoamine depletion with vesicular
monoamine transporter inhibitor—reserpine. The observed antidepressant effect was not affected by
catecholamine depletion with the tyrosine hydroxylase inhibitor, α-methyl-p-tyrosine (AMPT). Similarly
XAE did not potentiate the toxicity of a sub-lethal dose of noradrenaline. XAE had a synergistic effect
with the glycineB receptor partial agonist, D-cycloserine and nitric oxide synthase inhibitor, L-NAME.
However established antidepressant effects of XAE were abolished by NMDA and NOS activation with D-
serine and L-arginine.
Conclusion: This study shows that Xylopia aethiopica has antidepressant potential largely due to effects
on 5-HT neurotransmission with possible glutamatergic effect through the glycineB co-binding site and
nitric oxide synthase inhibition
