中文摘要：

目的用多巴胺诱导的SH—SY5Y细胞凋亡模型，研究从小蜡树皮提取的单体化合物liriodendrin的神经保护作用。方法应用MTT法检测liriodendrin对细胞存活率的影响。应用Annexin V-FITC与PI双染流式法检测firiodendrin对多巴胺诱导的细胞凋亡的影响。应用荧光染料DCFH—DA及Rhodamine123对细胞内活性氧簇（ROS）及线粒体膜电位（Δψm）进行了检测。此外，应用RT—PCR方法，对细胞内P53基因的转录水平进行了检测。结果在经过10^-8，10^-7，10^-6，10^-5及10^-4mol·L^-1浓度liriodendrin处理后，细胞存活率与多巴胺处理组相比有显著性提高。流式细胞术结果显示liriodendrin具有显著的抗细胞凋亡作用。同时liriodendrin可明显改善多巴胺引起的 Δψm下降，并可以逆转多巴胺诱导的ROS水平升高。此外，liriodendrin还可以降低多巴胺引起的P53基因转录水平的升高。结论Liriodendrin对多巴胺诱导的细胞损伤有明显保护作用。推测主要机制可能与其调节细胞氧化应激反应及细胞凋亡的信号转导通路有关，提示该化合物可以作为治疗退行性神经疾病如帕金森氏病等的候选化合物。

英文摘要：

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）