Background: Gladiolus dalenii
Van Geel (Iridaceae) has been used for the treatment of depression and psychotic disorders in African traditional
medicine. The aim of this study was to assess the effect of the aqueous extract from the corm of Gladiolus dalenii
and its possible mechanisms of
Materials and Methods:
We assessed the antidepressant properties of G. dalenii
corm aqueous extract in mice, using the open field, forced
swimming, and tail suspension tests. Spontaneous locomotor activity of mice given various doses of G. dalenii
extract (per os
) was determined in
the open field, whereas immobility was evaluated in the other two tests.
Extract maximal effect was observed at 15 mg/kg, as mice displayed a marked reduction in immobility time in both the forced
swimming test (80%) and the tail suspension test (66%). In further studies aimed at investigating the mechanism of action of G. dalenii
the latter significantly antagonized the effect of N-methyl-D- aspartate (NMDA, 75 mg/kg) at both the doses 15 mg/kg (p<0.001) and 150 mg/kg
(p=0.004). A significant reduction in immobility time was also observed following treatment with combinations of a sub-effective dose of extract
(7.5 mg/kg) with either the NMDA receptor antagonist D-(-)-2-amino-7-phosphonoheptanoic acid (D-AP7, 50 mg/kg, P< 0.001), the serotonin
reuptake inhibitor fluoxetine (5 and 10 mg/kg, P< 0.001and P< 0.001 respectively), and the multi-target antidepressant imipramine (5 and 10
mg/kg, P< 0.001and P< 0.001 respectively). Moreover, neither G. dalenii
extract alone nor its combinations with NMDA ligands imipramine and
fluoxetine enhanced mouse spontaneous locomotor activity.
Altogether, these results suggest that G. dalenii
has antidepressant properties, probably mediated through interactions with NMDA,
serotonin and/ or noradrenergic systems, and may justify its use in traditional medicine.