Laboratory of Mutagenesis and Carcinogenesis, Cancer Research Institute, Slovak Academy of Sciences 833 91Bratislava, Slovakia.
Mutagenesis. 2012 Sep;27(5):581-8. doi: 10.1093/mutage/ges023. Epub 2012 Apr 27.
Experimental evidences suggest that most essential oils possess a wide range of biological and pharmacological activities that may protect tissues against oxidative damage. In this study, we investigated DNA-protective effect of borneol, a component of many essential oils, against oxidative DNA damage induced in primary cultures of rat hepatocytes. Borneol was added to drinking water of Sprague-Dawley rats and DNA resistance against oxidative agents was compared in hepatocytes originated from control and borneol-treated rats. Oxidative stress induced by visible light-excited methylene blue (MB/VL) or 2,3-dimethoxy-1,4-naphthoquionone (DMNQ) resulted in increased levels of DNA lesions measured by the modified single cell gel electrophoresis. Borneol (17 or 34 mg/kg body weight) added to drinking water of rats for 7 days reduced the level of oxidative DNA lesions induced in their hepatocytes by MB/VL or DMNQ. To explain the increased resistance of DNA towards oxidative stress, we measured the base-excision repair (BER) capacity in liver cell extracts of control and borneol-supplemented rats on DNA substrate of HepG2 cells containing oxidative damage. Our results showed that administration of borneol in drinking water had no effect on incision activity of hepatocytes isolated from supplemented rats. The spectrophotometric assessment of enzymatic antioxidants superoxide dismutase (SOD) and glutathione peroxidase (GPx) activities and the flow cytometric assessment of total intracellular glutathione (iGSH) in primary hepatocytes of borneol-supplemented rats showed no changes in SOD and GPx activities but higher iGSH content particularly in hepatocytes of higher borneol dose (34 mg/kg) supplemented rats in comparison to control animals. Despite the fact that borneol had no effect either on BER of oxidative DNA damage or on the levels of antioxidant enzymes and manifested no reducing power and radicals scavenging activity, it increased significantly the level of non-enzymatic antioxidant iGSH which could reduce the oxidative DNA lesions induced by MB/VL or DMNQ.
实验证据表明，大多数精油具有广泛的生物和药理活性，可以保护组织免受氧化损伤。在这项研究中，我们研究了龙脑，许多精油的成分，对原代培养大鼠肝细胞中氧化诱导的 DNA 损伤的 DNA 保护作用。将龙脑添加到 Sprague-Dawley 大鼠的饮用水中，并比较来自对照和龙脑处理大鼠的肝细胞中对氧化剂的 DNA 抗性。可见光激发的亚甲蓝（MB/VL）或 2,3-二甲氧基-1,4-萘醌（DMNQ）诱导的氧化应激导致通过改良的单细胞凝胶电泳测量的 DNA 损伤水平增加。将龙脑（17 或 34mg/kg 体重）添加到大鼠饮用水中 7 天，可降低 MB/VL 或 DMNQ 诱导其肝细胞中氧化 DNA 损伤的水平。为了解释 DNA 对氧化应激的抗性增加，我们在含有氧化损伤的 HepG2 细胞 DNA 底物上测量了对照和龙脑补充大鼠肝细胞提取物中的碱基切除修复（BER）能力。我们的结果表明，饮用水中添加龙脑对补充大鼠分离的肝细胞的切口活性没有影响。分光光度法评估超氧化物歧化酶（SOD）和谷胱甘肽过氧化物酶（GPx）的酶促抗氧化剂活性和补充龙脑的原代肝细胞的总细胞内谷胱甘肽（iGSH）的流式细胞术评估显示，SOD 和 GPx 活性没有变化，但 iGSH 含量较高，特别是在补充龙脑剂量较高（34mg/kg）的大鼠肝细胞中，与对照动物相比。尽管龙脑既没有影响氧化 DNA 损伤的 BER，也没有影响抗氧化酶的水平，也没有表现出还原能力和自由基清除活性，但它显著增加了非酶促抗氧化剂 iGSH 的水平，从而降低了 MB/VL 或 DMNQ 诱导的氧化 DNA 损伤。
