Effect of daidzein on anxiety, social behavior and spatial learning in male Balb/cJ mice

Daidzein is an abundant isoflavone present in soy. It is unique as it can be further metabolized into equol, a compound with greater estrogenic activity than other isoflavones. The potential benefit of daidzein in the prevention of various cancers and cardiovascular diseases has drawn attention to this molecule and isoflavone consumption is increasing around the world. However, it remains unclear whether daidzein affects locomotor activity, anxiety, social behavior or spatial memory. Here we report the results from a range of tests designed to assess anxiety, social behavior and spatial learning and memory in male Balb/cJ mice following consumption of daidzein for 30 days. We found that daidzein treatment significantly increased locomotor activity in the open field, elevated plus-maze and Morris water-maze tests; resulted in increased amicable behavior, decreased aggression and decreased sexual behavior during social interaction tests; and resulted in an anxiolytic effect amongst treated males. We found no effect of daidzein consumption on the acquisition and retrieval of spatial memory. Our results suggest that long-term consumption of daidzein may produce significant effects on locomotor activity, mood and social behavior without significant effects on learning and memory.