Induction of glutathione-dependent hepatic biotransformation enzymes by lycopene in the hamster cheek pouch carcinogenesis model.

Consumption of carotenoids is recognised to be inversely related with cancer incidence. Lycopene, a major carotenoid in tomatoes is a potent antioxidant with potential anticarcinogenic properties. We undertook the study to investigate the effect of lycopene on hepatic biotransformation enzymes during 7,12-dimethylbenz[a]anthracene (DMBA)-induced hamster buccal pouch (HBP) carcinogenesis using hepatic lipid peroxidation, reduced glutathione (GSH) and biotransformation enzymes that use GSH as a substrate such as glutathione peroxidase (GPx), glutathione-S-transferase (GST) and glutathione reductase (GR). Enhanced lipid peroxidation in the liver of tumour-bearing animals was accompanied by significant decreases in the activities of GSH and GSH-dependent enzymes. Administration of lycopene significantly decreased the formation of lipid peroxides and enhanced the activities of hepatic biotransformation enzymes. Our results indicate that elevation of hepatic GSH and biotransformation enzymes by lycopene may play a key role in preventing cancer development at extrahepatic sites.