| Abstrakt: |
Four dietary, naturally occurring anticarcinogens (flavone, coumarin, α-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 α-angelicalactone (125, 240 and 155% respectively) and in the stomach by coumarin and α-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 α GSTs were induced in the oesophagus by flavone, coumarin and α-angelicalactone (570, 1580 and 570%), but did not change in the stomach. GST-α was undetectable in the pancreas. GST-μ was expressed at high levels in all three tissues investigated, but only pancreatic GST-μ levels of ellagic acid-fed rats were increased (160%). GST-π was induced in the stomach by coumarin and α-angelicalactone (470 and 1120%) and in the pancreas by flavone (200%). GST-π 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 α-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. [ABSTRACT FROM PUBLISHER] |
