Potent protective effect of isoimperatorin against aflatoxin B1-inducible cytotoxicity in H4IIE cells: bifunctional effects on glutathione S-transferase and CYP1A.
Potent protective effect of isoimperatorin against aflatoxin B1-inducible cytotoxicity in H4IIE cells: bifunctional effects on glutathione S-transferase and CYP1A.
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DOI：
10.1093/carcin/bgl118
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发表时间：
2006-12
期刊：
影响因子：
4.7
通讯作者：
Yuba Raj Pokharel;E. Han;Ji Young Kim;S. Oh;S. K. Kim;E. Woo;H. Jeong;K. Kang
中科院分区：
文献类型：
--
作者：
Yuba Raj Pokharel;E. Han;Ji Young Kim;S. Oh;S. K. Kim;E. Woo;H. Jeong;K. Kang
通常，化学预防剂诱导II相解毒酶或抑制致癌物代谢所需的细胞色素P450酶（CYP）。本研究从枳壳中分离得到一个香豆素类化合物异欧前胡素，并研究其对黄曲霉毒素B1（AFB 1）诱导的H4 IIE细胞毒性的保护作用。异欧前胡素（>0.3 μ M）可显著抑制AFB 1的细胞毒性作用。CDNB [1-氯-2，4-二硝基苯;谷胱甘肽S-转移酶（GST）亚型-非特异性]和NBD（7-氯-4-硝基苯并-2-氧杂-1，3-二唑; GST α型特异性）测定显示，异欧前胡素（0.3-3 μ M）以浓度依赖性方式增加GST活性。使用亚型特异性抗体的蛋白质印迹分析证实，GST α蛋白，而不是GSTmu或GSTpi，在用异欧前胡素处理的细胞中诱导。报告基因分析使用的抗氧化剂反应元件（ARE）含有构建体和亚细胞分级分离试验表明，GST α诱导异欧前胡素与Nrf 2/ARE激活。此外，乙氧基试卤灵-O-脱乙基酶试验表明，异欧前胡素（2 μ M）完全抑制3-甲基choranthrene诱导的CYP 1A活性。这些结果表明，枳壳中的异欧前胡素是有效成分。对黄曲霉毒素B1具有有效的肝保护作用，可能是通过诱导GST α和直接抑制CYP 1A，并表明异欧前胡素应被认为是一种潜在的化学预防剂。
Typically chemopreventive agents either induce phase II detoxifying enzymes or inhibit the cytochrome P450 enzymes (CYPs) that are required for the metabolism of carcinogens. In this study, we isolated a coumarin compound, isoimperatorin from Poncirus trifoliata Raf., and studied its protective effects against aflatoxin B1 (AFB1)-induced cytotoxicity in H4IIE cells. Isoimperatorin (>0.3 microM) significantly inhibited the cytotoxic effect of AFB1. CDNB [1-chloro-2,4-dinitrobenzene; glutathine S-transferase (GST) subtype-non-specific] and NBD (7-chloro-4-nitrobenzo-2-oxa-1,3-diazole; GSTalpha type-specific) assays revealed that isoimperatorin (0.3-3 microM) increased GST activity in a concentration-dependent manner. Western blot analyses using subtype-specific antibodies confirmed that GSTalpha protein, but not GSTmu or GSTpi, was induced in cells treated with isoimperatorin. Reporter gene analysis using an antioxidant response element (ARE) containing construct and subcellular fractionation assays revealed that GSTalpha induction by isoimperatorin is associated with Nrf2/ARE activation. Moreover, ethoxyresorufin-O-deethylase assays showed that isoimperatorin (2 microM) completely inhibited 3-methylchoranthrene-inducible CYP1A activity. These results indicate that isoimperatorin from Poncirus trifoliata Raf. possesses a potent hepatoprotective effect against AFB1, presumably through the induction of GSTalpha and the direct inhibition of CYP1A, and suggest that isoimperatorin should be considered a potential chemopreventive.