Flavonoids, centaurein and centaureidin, from Bidens pilosa, stimulate IFN- expression

Bidens pilosa is used as an ethnical medicine for bacterial infection or immune modulation in Asia, America and Africa. Here, we employed n IFNpromoter-driven luciferase reporter construct and T cells to characterize immunomodulatory compounds from this plant based on a ioactivity-guided isolation principle. We found that PHA, a positive control, caused a six-fold increase in IFNpromoter activity. In contrast, hot ater crude extracts from Bidens pilosa and its butanol subfraction increased IFNpromoter activity to twoand six-fold, respectively. Finally, entaurein (EC50 = 75 g/ml) and its aglycone, centaureidin (EC50 = 0.9 g/ml), isolated from this butanol subfraction, augmented IFNpromoter ctivity by ∼four-fold. Consistent with the role of centaurein or its aglycone in IFNregulation, we showed that centaurein induced the activity f NFAT and NF B enhancers, located within the IFNpromoter, in Jurkat cells. Overall, our results showed that centaurein regulated IFNranscription, probably via NFAT and NF B in T cells. 2007 Elsevier Ireland Ltd. All rights reserved.