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HERO ID
1310212
Reference Type
Journal Article
Title
Effects of tea catechins on the ERE-regulated estrogenic activity
Author(s)
Kuruto-Niwa, R; Inoue, S; Ogawa, S; Muramatsu, M; Nozawa, R
Year
2000
Is Peer Reviewed?
Yes
Journal
Journal of Agricultural and Food Chemistry
ISSN:
0021-8561
EISSN:
1520-5118
Volume
48
Issue
12
Page Numbers
6355-6361
Language
English
PMID
11312808
Abstract
Tea catechins exert many biological effects, including anticancer and antibacterial activities. Also, it is reported that some plant flavonoids exhibit estrogenic activity. In this study, we investigated estrogenic or antiestrogenic activities of catechins in HeLa cells transiently transfected with an estrogen response element (ERE)-regulated luciferase reporter and an estrogen receptor (ER) alpha or ERbeta expression vector. Catechins alone did not induce luciferase (luc) activity in either of the ERs. Addition of 17beta-estradiol (E2) plus epicatechin gallate (ECG) or epigallocatechin gallate (EGCG) at 5 x 10(-6) M resulted in significant decreases in the ERalpha-mediated luc activity compared with that of E2 alone. On the contrary, lower concentrations significantly increased the E2-induced luc activity. Similar effects were observed with tamoxifen. The ERbeta-mediated estrogenic activities were stimulated by catechins. In conclusion, some catechins, particularly EGCG, were antiestrogenic for ERalpha at higher doses, and co-estrogenic for ERalpha at lower doses and for ERbeta. The lower doses were found in human plasma after tea-drinking. In addition, some catechins may be antiendocrine disruptors because they suppressed bisphenol A-induced luc activities.
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