Nijhoff W A, Peters W H
Department of Gastroenterology, University Hospital St Radboud, Nijmegen, The Netherlands.
Carcinogenesis. 1994 Sep;15(9):1769-72. doi: 10.1093/carcin/15.9.1769.
Four dietary, naturally occurring anticarcinogens (flavone, coumarin, alpha-angelicalactone and ellagic acid) were studied with respect to their effects on oesophageal, gastric and pancreatic (i) glutathione S-transferase (GST) enzyme activity, (ii) GST isozyme levels and (iii) glutathione (GSH) content in male Wistar rats. GST enzyme activity was significantly increased in the oesophagus by flavone, coumarin and alpha-angelicalactone (125, 240 and 155% respectively) and in the stomach by coumarin and alpha-angelicalactone (140 and 230%). No change in pancreatic GST activity was observed. In addition, class- and tissue-specific changes in GST isozyme levels occurred. Class alpha GSTs were induced in the oesophagus by flavone, coumarin and alpha-angelicalactone (570, 1580 and 570%), but did not change in the stomach. GST-alpha was undetectable in the pancreas. GST-mu was expressed at high levels in all three tissues investigated, but only pancreatic GST-mu levels of ellagic acid-fed rats were increased (160%). GST-pi was induced in the stomach by coumarin and alpha-angelicalactone (470 and 1120%) and in the pancreas by flavone (200%). GST-pi was detectable at low levels in rat oesophageal epithelium of coumarin-fed animals only. GSH concentrations were uninfluenced by the dietary anticarcinogens in all tissues. These results suggest that dietary ellagic acid and, more especially, flavone, coumarin and alpha-angelicalactone may exert strong chemoprotective effects by selective enhancement of members of the GST detoxification system in the oesophagus or stomach and, to a lesser extent, in the pancreas.
研究了四种膳食中天然存在的抗癌物质（黄酮、香豆素、α-当归内酯和鞣花酸）对雄性Wistar大鼠食管、胃和胰腺的以下影响：（i）谷胱甘肽S-转移酶（GST）活性；（ii）GST同工酶水平；（iii）谷胱甘肽（GSH）含量。黄酮、香豆素和α-当归内酯可使食管中的GST酶活性显著增加（分别为125%、240%和155%），香豆素和α-当归内酯可使胃中的GST酶活性增加（分别为140%和230%）。胰腺GST活性未观察到变化。此外，GST同工酶水平出现了类别和组织特异性变化。黄酮、香豆素和α-当归内酯可使食管中α类GST诱导增加（分别为570%、1580%和570%），但胃中未发生变化。胰腺中未检测到GST-α。GST-μ在所有三个研究组织中均高水平表达，但仅鞣花酸喂养大鼠的胰腺GST-μ水平增加（160%）。香豆素和α-当归内酯可使胃中GST-π诱导增加（分别为470%和1120%），黄酮可使胰腺中GST-π诱导增加（200%）。仅在香豆素喂养动物的大鼠食管上皮中可检测到低水平的GST-π。所有组织中的GSH浓度均不受膳食抗癌物质的影响。这些结果表明，膳食中的鞣花酸，尤其是黄酮、香豆素和α-当归内酯，可能通过选择性增强食管或胃以及程度较小的胰腺中GST解毒系统的成员发挥强大的化学保护作用。
