Effects of kale ingestion on pharmacokinetics of acetaminophen in rats

Kale is a cruciferous vegetable (Brassicaceae) that contains a large amount of health-promoting phytochemicals. The chronic ingestion of cabbage of the same family is known to accelerate conjugating acetaminophen (AA) and decrease the plasma AA level. Therefore, we examined to clarify the effects of kale on the pharmacokinetics of AA, its glucuronide (AA-G) and sulfate (AA-S). AA was orally administered to rats pre-treated with kale or cabbage (2000 mg/kg/day) for one week. Blood samples were collected from the jugular vein, and the concentrations of AA, AA-G and AA-S were determined. In results, kale ingestion induced an increase in the area under the concentration-time curve (AUC) and a decrease in the clearance of AA, whereas cabbage had almost no influence. In addition, there were significant differences in the AUC of AA-G between the control and kale groups. mRNA expression levels of UDP-glucuronosyltransferases, the enzymes involved in glucuronidation, in the kale group were significantly higher than those in the control group. In conclusion, kale ingestion increased the plasma concentrations of both AA and AA-G. The results suggest that kale ingestion accelerates the glucuronidation of AA, but an increase of plasma AA levels has a different cause than the cause of glucuronidation.