Abstract: ObjectiveTo assess the effects of peach blossom polyphenol(PBP) and levels of norepinephrine(NE) and 5-hydroxytryptamine(5-HT) in hippocampus of mice with chronic depression induced by unpredictable mild stress.MethodsBased on body weight and addiction to 1% sucrose water,50 Kuming mice were randomly divided into model control group,fluose fine hydrochloride(FFH) group,three PBP treatment groups at doses of 20 mg/kg,40 mg/kg,and 80 mg/kg.The depression model of the mice was induced by chronic unpredictable mild stress.The changes in behavior and hippocampus 5-HT,NE content of the mice were observed and compared among different groups.ResultsCompared with model group,the frequency of avoidance failure and immobility time of tail suspension in PBP treatment goups were significantly reduced with a dose-response manner(P<0.01).PBP treatment significantly increased brain 5-HT and NE levels(P<0.01) with an anti-depression effect similar to that of FFH.ConclusionPBP can significantly increase brain 5-HT and NE levels,which could be the mechanism of antidepressant effect of PBP.