Modulatory influence of arecanut on the mouse hepatic xenobiotic detoxication system and skin papillomagenesis.

The modulatory influence of arecanut, a masticatory in several human populations, on the levels of biotransformation system enzymes in mouse liver has been studied. Swiss albino mice of either sex (4 weeks old) were fed on diets containing 0.25%, 0.5%, or 1% arecanut (w/w) for 5 weeks. In addition, a group of mice received a 1% arecanut diet for 36 weeks. The findings revealed a significant increase in hepatic levels of cytochrome b5, cytochrome P-450, malondialdehyde (MDA), and glutathione S-transferase (GST). The hepatic -SH content was depressed by 0.5% and 1% arecanut diets. Long-term feeding of a 1% arecanut diet elicited changes similar to those seen following treatment for 5 weeks. Arecanut-modulated profiles of biotransformation enzymes and antioxidant levels are suggestive of its influence in the process of carcinogenesis induced by bioactivated electrophilic species of potential chemical carcinogens among habitual arecanut chewers. Arecanut was also tested for its potency either to induce or to alter 7,12-dimethylbenz[a]anthracene (DMBA)-induced papillomagenesis in the skin of the mouse. Animals put on a 1% arecanut diet and treated with a standard two-stage protocol for tumor induction developed a 5.41 tumor burden (control value: 5.76) along with 100% incidence of mice bearing papillomas (control value: 94.4%), thus signifying that dietary intake of 1% arecanut for 18 weeks could not induce/alter the mouse skin tumorigenesis pattern.