Singh Shraddha, Eapen Susan, D'Souza S F
Nuclear Agriculture and Biotechnology Division, Bhabha Atomic Research Centre, Trombay, Mumbai 400 085, India.
Chemosphere. 2006 Jan;62(2):233-46. doi: 10.1016/j.chemosphere.2005.05.017. Epub 2005 Jul 1.
Bacopa monnieri L. plants exposed to 10, 50, 100 and 200 microM cadmium (Cd) for 48, 96 and 144 h were analysed with reference to the accumulation of metal and its influence on various enzymatic and non-enzymatic antioxidants, thiobarbituric acid reactive substances (TBARS), photosynthetic pigments and protein content. The accumulation of Cd was found to be increased in a concentration and duration dependent manner with more Cd being accumulated in the root. TBARS content of the treated roots and leaves increased with increase in Cd concentration and exposure periods, indicating the occurrence of oxidative stress. Induction in the activities of superoxide dismutase (SOD), ascorbate peroxidase (APX) and guiacol peroxidase (GPX) was recorded in metal treated roots and leaves of B. monnieri. In contrast, a significant reduction in catalase activity in Cd treated B. monnieri was observed. An increase was also noted in the levels of cysteine and non-protein thiol contents of the roots of B. monnieri followed by a decline. However, in leaves, cysteine and non-protein thiol contents were found to be enhanced at all the Cd concentrations and exposure periods. A significant reduction in the level of ascorbic acid was observed in a concentration and duration dependent manner. The total chlorophyll and protein content of B. monnieri decreased with increase in Cd concentration at all the exposure periods. Results suggest that toxic concentrations of Cd caused oxidative damage as evidenced by increased lipid peroxidation and decreased chlorophyll and protein contents. However, B. monnieri is able to combat metal induced oxidative injury involving a mechanism of activation of various enzymatic and non-enzymatic antioxidants.
将莫氏婆罗门参（Bacopa monnieri L.）植株暴露于10、50、100和200微摩尔镉（Cd）中48、96和144小时，分析金属积累及其对各种酶促和非酶促抗氧化剂、硫代巴比妥酸反应性物质（TBARS）、光合色素和蛋白质含量的影响。发现Cd的积累呈浓度和时间依赖性增加，根部积累的Cd更多。处理过的根和叶的TBARS含量随Cd浓度和暴露时间的增加而增加，表明发生了氧化应激。在金属处理的莫氏婆罗门参的根和叶中，超氧化物歧化酶（SOD）、抗坏血酸过氧化物酶（APX）和愈创木酚过氧化物酶（GPX）的活性被诱导。相反，在Cd处理的莫氏婆罗门参中观察到过氧化氢酶活性显著降低。莫氏婆罗门参根部的半胱氨酸和非蛋白硫醇含量也先增加后下降。然而，在叶片中，在所有Cd浓度和暴露时间下，半胱氨酸和非蛋白硫醇含量均增加。抗坏血酸水平以浓度和时间依赖性方式显著降低。在所有暴露时间下，莫氏婆罗门参的总叶绿素和蛋白质含量随Cd浓度的增加而降低。结果表明，Cd的毒性浓度导致了氧化损伤，脂质过氧化增加以及叶绿素和蛋白质含量降低证明了这一点。然而，莫氏婆罗门参能够对抗金属诱导的氧化损伤，涉及激活各种酶促和非酶促抗氧化剂的机制。
