Anti-genotoxicity and glutathione S-transferase activity in mice pretreated with caffeinated and decaffeinated coffee.

In vivo anti-genotoxic effects of caffeinated and decaffeinated instant coffee were compared in mice after pretreatment either by gavage for 10 consecutive days or in the drinking water for 2 weeks. Changes in hepatic sulfhydryl (-SH) content and glutathione S-transferase (GST) activity were evaluated in pretreated animals. Both caffeinated and decaffeinated instant coffee induced a moderate increase in -SH content and GST activity following pretreatment (with 70, 140 and 280 mg/kg body weight) by gavage for 10 days. This enhancement was not always dose dependent. The maximum effect on GST activity was observed at a dose of 140 mg/kg body weight/day. However, such an effect was not observed after administration of drinking water containing 2% caffeinated/decaffeinated instant coffee for 2 weeks. Results of the bone marrow micronucleus test for evaluating genotoxic effects revealed that both caffeinated and decaffeinated instant coffee (140 mg/kg body weight/day) could exert significant anti-genotoxic effects against ip injected benzo[a]pyrene (BP), cyclophosphamide (CPH), 7,12-dimethylbenz[a]anthracene (DMBA), mitomycin C (MMC) and procarbazine (PCB) in animals pretreated by gavage. Anti-genotoxic effects against BP, DMBA and urethane (URE) were evaluated in animals that received drinking water containing 2% caffeinated/decaffeinated instant coffee for 2 weeks. With the exception of the anti-genotoxic effect of decaffeinated coffee against DMBA, there was no significant change in genotoxicity after the above pretreatment. From this work, there is no evidence for any significant difference in the in vivo anti-genotoxicity of caffeinated and decaffeinated instant coffee.