Abstract:[Objective] This study aims to investigate the anti -depression effects of enzymatic hydrolysates of mulberry leaf flavonoids (EMLF ).[Methods] EMLF was prepared and its components were analyzed by UPLC -MS.A zebrafish model of depression was induced by 40 mg/L reserpine.Six groups were designed,including the control,model,fluoxetine,L-EMLF (20 μg/mL ),M-EMLF (40 μg/mL ),and H-EMLF (80 μg/mL ) groups.Behavioral tests,including the new tank test and the light -dark box test,were conducted.The structural changes in the brain tissue of zebrafish in each group were observed by HE staining.The mRNA levels of interleukin -1β (IL-1β),tumor necrosis factor -α (TNF-α),tryptophan hydroxylase -2 (TPH- 2),and 5-hydroxytryptamine 2A (5-HT2A) receptor in the brain tissue were determined by q -PCR.The activity of superoxide dismutase (SOD ) and the level of reactive oxygen species (ROS ) in the brain tissue of zebrafish were measured.Metabolomics analysis was performed to identify differential metabolites and associated metabolic pathways.贾东升(1982—),男,河北省农林科学院副研究员,博士。E-mail:jiads 1@163.com|[Results]] UPLC -MS identified 10 flavonoid aglycone compounds.Reserpine (40 mg/L ) induced depression -like behaviors in zebrafish,while EMLF alleviated the bottom -dwelling and dark -preference behaviors,restored the orderly arrangement of nerve cells in the midbrain region,and increased the cell number.EMLF treatment down -regulated the mRNA levels of IL-1β,TNF-α,and 5-HT2A while up -regulating the mRNA level of TPH- 2.In addition,EMLF increased the SOD activity and reduced the ROS level.Metabolomics analysis revealed that EMLF significantly regulated 24 differential metabolites,primarily affecting purine metabolism,arginine and proline metabolism,tryptophan metabolism,and riboflavin metabolism.[Conclusion] EMLF effectively alleviated reserpine -induced depression in zebrafish,potentially by regulating the tryptophan metabolism,purine metabolism,and arginine and proline metabolism.