Aim To investigate the effect of liriodendrin, an extract from Fraxinus sielboldiana blume belonging to the Oleaceae family, on dopamine-induced cytotoxicity in human neuroblastoma SH-SY5Y cells. Methods Cell viability was processed when treated with 50 μmol·L^-1 of dopamine for 24 h by MTT assay. Early apoptosis, late apoptosis/necrosis were analyzed by flow cytometry using Annexin V-FITC and propidium iodide （PI） double-staining, respectively. Generation of reactive oxygen species （ROS） was assessed by DCFH-DA, an oxidation-sensitive fluorescent probe. To evaluate mitochondrion membrane potential （Δψm） using flow cytometry with the fluorescent dye Rhodamine 123. The transcriptional level of P53 was studied using RT- PCR. Results The dopamine-induced loss of cell viability was significantly attenuated by liriodendrin treatment at the concentration of 10^-8, 10^-7, 10^-6, 10^-5 and 10^-4 mol·L^-1. The protective effects of liriodendrin （10^-7, 10^-6 and 10^-5 mol·L^-1） on dopamine-induced cytotoxicity may be ascribed to its anti-oxidative properties by reducing ROS level and anti-apoptotic effect via protection of Δψm. In addition, the effect of liriodendrin may involve the P53 pathway in apoptosis. Conclusion Liriodendrin may provide a useful therapeutic strategy for the treatment of neurodegenerative diseases such as Parkinson＇s disease （PD）
