Abstract
Objectives Depression is a complex neuropsychiatric disorder, which affects the quality of life
of the sufferers and treatment approach is associated with serious adverse effects
and sometimes therapeutic failures. Cymbopogon citratus leaf (CC) has been reported to exert anti-depressant effect but its mechanism of action
is yet to be elucidated hence, the need for this study.
Methods The anti-depressant-like effect of Cymbopogon citratus aqueous leaf was evaluated using forced swim test (FST), tail suspension test (TST)
and yohimbine-induced lethality test (YLT) in aggregated mice. Interaction studies
involving p-chlorophenylalanine (pCPA), an inhibitor of serotonin biosynthesis and
yohimbine, α2-adrenergic receptor antagonist were carried out to evaluate the role of monoaminergic
system in the anti-depressant-like effect of CC. The effect of CC on spontaneous motor
activity (SMA) was also assessed using activity cage.
Results Cymbopogon citratus (25 and 50 mg/kg, p.o.) demonstrated antidepressant-like activity devoid of significant
stimulation of the SMA in mice. However, the antidepressant-like property of CC was
significantly (p<0.05) attenuated by pretreatment with yohimbine suggesting involvement
of noradrenergic pathway in the action of the extract. Also, pCPA reversed the anti-immobility
effect of CC, indicating the role of serotonergic system in the mediation of its antidepressant
activity. Moreover, CC (25 and 50 mg/kg) potentiated the lethal effect of yohimbine
in aggregated mice, which further suggest the involvement of monoaminergic systems
in its action.
Conclusions The results of the study showed that C. citratus might be interacting with serotonergic and noradrenergic pathways to mediate its
anti-depressant-like effect in mice.
Key words
Cymbopogon citratus - anti-depression - serotonergic - noradrenergic
