We previously showed that extracts of Sargassum fusiforme significantly reduce immobility time in the
forced swim test and tail suspension test, suggesting that these extracts possess antidepressant-like
effects. Here, fucosterol extracted from S. fusiforme was evaluated for antidepressant and anticonvulsant
activities in mice. Fucosterol (10, 20, 30 and 40 mg/kg) significantly shortened immobility time in the
forced swim test and tail suspension test for30 min after treatment but had no effect on locomotor
activity in the open field test. Fucosterol significantly increased serotonin, norepinephrine and the metabolite
5-hydroxyindoleacetic acid in mouse brain, suggesting that the effects of fucosterol may be
mediated through these neurotransmitters. As assessed using maximal electroshock, fucosterol (20, 40,
100 mg/kg) possessed anticonvulsant activity, whereas rotarod toxicity test results indicated that fucosterol
did not induce neurotoxicity at the same dose levels in mice. Thus, fucosterol may be a useful
antidepressant adjunct candidate for treating depression in patients with epilepsy. A significant increase
in hippocampal brain-derived neurotrophic factor (BDNF) levels was found in the fucosterol 20 mg/kg
group (Po0.05). Our findings suggested that fucosterol may possess an antidepressant-like effect, which
may be mediated by increasing central BDNF levels.