INDUCTION OF GLUTATHIONE-S-TRANSFERASE ACTIVITY IN HEPG2 CELLS BY EXTRACTS FROM FRUITS AND VEGETABLES

The human hepatoma cell line, hepG2, retains many of the xenobiotic me tabolising enzymes found in normal hepatocytes, including an inducible glutathione S-transferase (GST). The isoform of GST that is induced b y xenobiotics in this cell line is GSTA1-1. As a first step to determi ning the effect of diet on induction of GST in humans, we have examine d the ability of extracts from a wide variety of fruits and vegetables to induce GST activity in hepG2 cells. Extracts from cruciferous vege tables (broccoli, Brussels sprouts, cabbage) were the most potent indu cers, but this was dependent on the variety. Most of the extracts from fruits, with the exception of grapefruit, were poor inducers. Similar ities and differences between the induction of GST and of quinone redu ctase in mouse hepa1c1c7 cells are discussed. The results show that ex tracts from cruciferous vegetables are effective inducers of human GST , in agreement with previous studies on GST in animals and cell lines derived from animals. (C) 1997 Elsevier Science Ltd.