Antidepressant-like activity of the aqueous extract of Allium macrostemon in mice

Aim of the study: The aim of this study was to identify the effects of water extracts of Allium macrostemon Bunge (AM-W), a traditional herb, in mice. Materials and methods: The antidepressant-like activities of AM-W were evaluated through behavioral despair in forced swimming test and tail suspension test. To elucidate the mode of action of the antidepressant-like effects of AM-W, new born cells in the subgranular zone and the granule cell layer were analyzed by immunostaining for incorporation of 5-bromo-2-deoxyuridine (BrdU). In addition, the effects of AM-W on the expression levels of brain-derived neurotrophic factor (BDNF) were investigated by western blotting and immunohistochemistry. Results: The administration of AM-W reduced the immobility duration in the forced swimming test and tail suspension test (100 or 200. mg/kg, P<0.05). Sub-chronic administration of AM-W (100 or 200. mg/kg, p.o., for 14 days) increased the number of BrdU-incorporating cells. The percentage of BrdU-incorporating cells co-localized with NeuN was significantly increased after AM-W administration (100 or 200. mg/kg, P<0.05). Moreover, the expression levels of BDNF which is reported to be associated with neurogenesis were significantly increased in the hippocampus after administration of AM-W. Conclusions: These results suggest that AM-W may be a good antidepressant, and that its mechanism of action may be related to its positive effects on neurogenesis and BDNF release.