Antidepressant-like effect of macranthol isolated from Illicium dunnianum tutch in mice

The present study was aimed to evaluate the behavioral and biochemical effects of macranthol, a triphenyl lignan isolated from Illicium dunnianum. To this aim, mice were treated with macranthol (10, 20 and 40 mg/kg) and then subjected to the forced swimming test, tail suspension test and chronic unpredictable mild stress. It was observed that macranthol significantly reduced the immobility time in the forced swimming test and tail suspension test after acute (1-day) treatment, and reversed the reduction of sucrose preference induced by chronic unpredictable mild stress after chronic (5-week) treatment. In addition, macranthol completely ameliorated the corticosterone hypersecretion by acute swim stress or chronic unpredictable mild stress. Chronic macranthol treatment attenuated the reduction of serotonergic neurotransmission in brain regions of frontal cortex and hippocampus. Taken together, our findings suggested that macranthol produced an antidepressant-like effect, which may be mediated by serotonergic and neuroendocrine system. Moreover, the finding that only chronic but not acute treatment enhanced brain-derived neurotrophic factor (BDNF) expression suggested that macranthol did not produce a rapid antidepressant-like response and long-term treatment was required in its clinical application.