Browsing by Author "Shyur, Lie-Fen"

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Cytopiloyne, a novel polyacetylenic glucoside from Bidens pilosa, functions as a T helper cell modulator
(2007-04-04)
Chiang, Yi-Ming
;
Chang, Cicero Lee-Tian
;
Chang, Shu-Lin
;
Yang, Wen-Chin
;
Shyur, Lie-Fen
An extract of Bidens pilosa, an anti-diabetic Asteraceae plant, has recently been reported to modulate T cell differentiation and prevent the development of non-obese diabetes (NOD) in NOD mice. In this paper, a novel bioactive polyacetylenic glucoside, cytopiloyne (1), was identified from the Bidens pilosa extract using ex vivo T cell differentiation assays based on a bioactivity-guided fractionation and isolation procedure. Its structure was elucidated as 2 beta-D-glucopyranosyloxy-1-hydroxytrideca-5,7,9,11-tetrayne by various spectroscopic methods. Functional studies showed that cytopiloyne was able to inhibit the differentiation of naive T helper (Th0) cells into type I T helper (Th1) cells but to promote the differentiation of Th0 cells into type II T helper (Th2) cell. Accordingly, cytopiloyne also suppressed IFN-gamma expression and promoted IL-4 expression in mouse splenocytes ex vivo. These results suggest that cytopiloyne functions as a T cell modulator that may directly contribute to the ethnopharmacological effect of Bidens pilosa extract on preventing diabetes. Moreover, cytopiloyne can serve as an index compound for quality control of lot-to-lot extract preparations of Bidens pilosa. (c) 2006 Elsevier Ireland Ltd. All rights reserved.
Flavonoids, centaurein and centaureidin, from Bidens pilosa, stimulate IFN-gamma expression
(2007-06-13)
Chang, Shu-Lin
;
Chiang, Yi-Ming
;
Chang, Cicero Lee-Tian
;
Yeh, Hsu-Hua
;
Shyur, Lie-Fen
Bidens pilosa is used as an ethnical medicine for bacterial infection or immune modulation in Asia, America and Africa. Here, we employed an IFN-gamma promoter-driven luciferase reporter construct and T cells to characterize immunomodulatory compounds from this plant based on a bioactivity-guided isolation principle. We found that PHA, a positive control, caused a six-fold increase in IFN-gamma promoter activity. In contrast, hot water crude extracts from Bidens pilosa and its butanol subfraction increased IFN-gamma promoter activity to two- and six-fold, respectively. Finally, centaurein (EC50 = 75 mu g/ml) and its aglycone, centaureidin (EC50 = 0.9 mu g/ml), isolated from this butanol subtraction, augmented IFN-gamma promoter activity by similar to four-fold. Consistent with the role of centaurein or its aglycone in IFN-gamma regulation, we showed that centaurein induced the activity of NEAT and NF kappa B enhancers, located within the IFN-gamma promoter, in Jurkat cells. Overall, our results showed that centaurein regulated IFN-gamma transcription, probably via NFAT and NF kappa B in T cells. (c) 2007 Elsevier Ireland Ltd. All rights reserved.