Gebhardt R
Physiologisch-Chemisches Institut, University of Tübingen, Germany.
Toxicol Appl Pharmacol. 1997 Jun;144(2):279-86. doi: 10.1006/taap.1997.8130.
Primary rat hepatocyte cultures exposed to tert-butylhydroperoxide (t-BHP) or cumene hydroperoxide were used to assess the antioxidative and protective potential of water-soluble extracts of artichoke leaves. Both hydroperoxides stimulated the production of malondialdehyde (MDA), particularly when the cells were pretreated with diethylmaleate (DEM) in order to diminish the level of cellular glutathione (GSH). Addition of artichoke extracts did not affect basal MDA production, but prevented the hydroperoxide-induced increase of MDA formation in a concentration-dependent manner when presented simultaneously or prior to the peroxides. The effective concentrations (down to 0.001 mg/ml) were well below the cytotoxic levels of the extracts which started above 1 mg/ml. The protective potential assessed by the LDH leakage assay and the MTT assay closely paralleled the reduction in MDA production and largely prevented hepatocyte necrosis induced by the hydroperoxides. The artichoke extracts did not affect the cellular level of glutathione (GSH), but diminished the loss of total GSH and the cellular leakage of GSSG resulting from exposure to t-BHP. Chlorogenic acid and cynarin accounted for only part of the antioxidative principle of the extracts which was resistant against tryptic digestion, boiling, acidification, and other treatments, but was slightly sensitive to alkalinization. These results demonstrate that artichoke extracts have a marked antioxidative and protective potential. Primary hepatocyte cultures seem suitable for identifying the constituents responsible for these effects and for elucidating their possible mode of action.
将原代大鼠肝细胞培养物暴露于叔丁基过氧化氢（t-BHP）或氢过氧化异丙苯中，以评估洋蓟叶水溶性提取物的抗氧化和保护潜力。两种氢过氧化物均刺激丙二醛（MDA）的产生，尤其是当细胞用马来酸二乙酯（DEM）预处理以降低细胞内谷胱甘肽（GSH）水平时。添加洋蓟提取物不会影响基础MDA的产生，但当与过氧化物同时存在或在过氧化物之前加入时，能以浓度依赖的方式阻止氢过氧化物诱导的MDA形成增加。有效浓度（低至0.001 mg/ml）远低于提取物的细胞毒性水平，提取物的细胞毒性水平在1 mg/ml以上开始出现。通过乳酸脱氢酶（LDH）泄漏试验和MTT试验评估的保护潜力与MDA产生的减少密切平行，并在很大程度上防止了氢过氧化物诱导的肝细胞坏死。洋蓟提取物不影响细胞内谷胱甘肽（GSH）水平，但减少了因暴露于t-BHP而导致的总GSH损失和GSSG的细胞泄漏。绿原酸和洋蓟酸仅占提取物抗氧化原理的一部分，该抗氧化原理对胰蛋白酶消化、煮沸、酸化和其他处理具有抗性，但对碱化略有敏感。这些结果表明洋蓟提取物具有显著的抗氧化和保护潜力。原代肝细胞培养似乎适合于鉴定造成这些作用的成分并阐明其可能的作用方式。
