Pomegranate juice inhibits sulfoconjugation in caco-2 human colon carcinoma cells

ABSTRACT Several fruit juices have been reported to cause food–drug interactions, mainly affecting cytochrome P450 activity; however, little is known about the effects of fruit juices on conjugation reactions. Among several fruit juices tested (apple, peach, orange, pineapple, grapefruit, and pomegranate), pomegranate juice potently inhibited the sulfoconjugation of 1-naphthol in Caco-2 cells. This inhibition was both dose- and culture time-dependent, with a 50% inhibitory concentration (IC50) value calculated at 2.7% (vol/vol). In contrast, no obvious inhibition of glucuronidation of 1-naphthol in Caco-2 cells was observed by any of the juices examined. Punicalagin, the most abundant antioxidant polyphenol in pomegranate juice, was also found to strongly inhibit sulfoconjugation in Caco-2 cells with an IC50 of 45 μM, which is consistent with that of pomegranate juice. These data suggest that punicalagin is mainly responsible for the inhibition of sulfoconjugation by pomegranate juice. We additionally dem...