Biochemistry Laboratory, Central Leather Research Institute, Adyar, Chennai, India.
Free Radic Biol Med. 2011 Dec 1;51(11):2090-107. doi: 10.1016/j.freeradbiomed.2011.09.009. Epub 2011 Sep 16.
The phytochemicals plumbagin and juglone have recently been gaining importance because of their various pharmacological activities. In this study, these compounds are shown to induce concentration- and time-dependent toxicity in human peripheral blood lymphocytes via the apoptotic pathway. Flow cytometry data revealed the occurrence of about 28% early apoptotic cells after 6h exposure to 10μM plumbagin and 35% late apoptotic cells and about 43% sub-G1 population after 24h. The cytotoxic effect of plumbagin was at least twofold higher than that of juglone as evidenced by the IC(50) value for cytotoxicity. Characteristic apoptotic features such as chromatin condensation and apoptotic body formation were observed through TEM, and membrane blebbing and cell surface smoothening were seen in SEM studies. Generation of ROS was evidenced through the HPLC analysis of superoxide-specific 2-OH-E+ formation. In addition, a decrease in GSH levels parallel to ROS production was observed. Reversal of apoptosis in both NAC- and Tempol-pretreated cells indicates the involvement of both ROS generation and GSH depletion in plumbagin- and juglone-induced apoptosis. The mechanistic pathway involves a decrease in MMP; alterations in the levels of Bcl-2, Bax, and cytosolic cytochrome c; and PARP-1 cleavage subsequent to caspase-3 activation.
植物化学物质白花丹素和胡桃醌由于其各种药理学活性而最近受到重视。在这项研究中，这些化合物通过凋亡途径被证明在人外周血淋巴细胞中诱导浓度和时间依赖性毒性。流式细胞术数据显示，在暴露于 10μM 白花丹素 6 小时后，约有 28%的早期凋亡细胞，24 小时后有 35%的晚期凋亡细胞和约 43%的亚 G1 群体。白花丹素的细胞毒性作用至少是胡桃醌的两倍，这可以通过细胞毒性的 IC50 值来证明。TEM 观察到特征性的凋亡特征，如染色质浓缩和凋亡小体形成，SEM 研究观察到细胞膜起泡和表面平滑。通过超氧化物特异性 2-OH-E+形成的 HPLC 分析证明了 ROS 的产生。此外，还观察到 GSH 水平与 ROS 产生平行下降。NAC 和 Tempol 预处理细胞中的凋亡逆转表明，ROS 的产生和 GSH 的耗竭都参与了白花丹素和胡桃醌诱导的凋亡。其机制途径包括 MMP 降低；Bcl-2、Bax 和胞质细胞色素 c 水平的改变；以及 caspase-3 激活后 PARP-1 切割。
