Yang Hsin-Ling, Chang Wen-Huei, Chia Yi-Chen, Huang Chin-Jung, Lu Fung-Jou, Hsu Hseng-Kuang, Hseu You-Cheng
Institute of Nutrition, China Medical University, Taichung, Taiwan.
Food Chem Toxicol. 2006 Dec;44(12):1978-88. doi: 10.1016/j.fct.2006.06.027. Epub 2006 Jul 18.
Toona sinensis (T. sinensis), well known in Taiwan as a traditional Chinese medicine, has been shown to exhibit antioxidant effects. In this study, therefore, the ability of T. sinensis to induce apoptosis was studied in cultured human premyelocytic leukemia HL-60 cells. Treatment of the HL-60 cells with a variety of concentrations of the aqueous extracts of T. sinensis (TS extracts) (10-75 microg/ml) and gallic acid (5-10 microg/ml), the natural phenolic components purified from TS extracts, resulted in dose- and time-dependent sequences of events marked by apoptosis, as shown by loss of cell viability and internucleosomal DNA fragmentation. Furthermore, apoptosis in the HL-60 cells was accompanied by the release of cytochrome c, caspase 3 activation and specific proteolytic cleavage of poly (ADP-ribose) polymerase (PARP). This increase in TS extracts- and gallic acid-induced apoptosis was also associated with a reduction in the levels of Bcl-2, a potent cell-death inhibitor, and an increase in those of the Bax protein, which heterodimerizes with and thereby inhibits Bcl-2. Interestingly, TS extracts- and gallic acid-induced dose-dependent reactive oxygen species (ROS) generation in HL-60 cells. We found that catalase significantly decreased TS extracts- or gallic acid-induced cytotoxicity, DNA fragmentation, and ROS production, however, slight reduction was observed with vitamins C and E. Our results indicate that TS extracts- or gallic acid-induced HL-60 apoptotic cell death could be due to the generation of ROS, especially H(2)O(2). The data suggest that T. sinensis exerts antiproliferative action and growth inhibition on HL-60 cells through apoptosis induction, and, therefore, that it may have anticancer properties valuable for application in food and drug products.
香椿在台湾作为一种传统中药广为人知，已被证明具有抗氧化作用。因此，在本研究中，我们研究了香椿诱导人早幼粒细胞白血病HL - 60细胞凋亡的能力。用不同浓度的香椿水提取物（TS提取物）（10 - 75微克/毫升）和从TS提取物中纯化得到的天然酚类成分没食子酸（5 - 10微克/毫升）处理HL - 60细胞，导致细胞凋亡呈现出剂量和时间依赖性的一系列事件，表现为细胞活力丧失和核小体间DNA片段化。此外，HL - 60细胞的凋亡伴随着细胞色素c的释放、半胱天冬酶3的激活以及聚（ADP - 核糖）聚合酶（PARP）的特异性蛋白水解切割。TS提取物和没食子酸诱导的凋亡增加还与强效细胞死亡抑制剂Bcl - 2水平的降低以及Bax蛋白水平的升高有关，Bax蛋白与Bcl - 2异二聚化从而抑制Bcl - 2。有趣的是，TS提取物和没食子酸在HL - 60细胞中诱导了剂量依赖性的活性氧（ROS）生成。我们发现过氧化氢酶显著降低了TS提取物或没食子酸诱导的细胞毒性、DNA片段化和ROS产生，然而，维生素C和E仅观察到轻微降低。我们的结果表明，TS提取物或没食子酸诱导的HL - 60细胞凋亡性死亡可能是由于ROS的产生，尤其是H₂O₂。数据表明，香椿通过诱导凋亡对HL - 60细胞发挥抗增殖作用和生长抑制作用，因此，它可能具有在食品和药品中应用的有价值的抗癌特性。
