Mol Nutr Food Res. 2015 Sep 23. doi: 10.1002/mnfr.201500479. [Epub ahead of print]

Phytoestrogenic activity of blackcurrant (Ribes nigrum) anthocyanins is mediated through estrogen receptor alpha.

Nanashima N1, Horie K2, Tomisawa T3, Chiba M1, Nakano M1, Fujita T4, Maeda H5, Kitajima M2, Takamagi S4, Uchiyama D6, Watanabe J2, Nakamura T1, Kato Y7.

• 1Department of Biomedical Sciences, Hirosaki University Graduate School of Health Sciences, 66-1 Hon-cho, Hirosaki, 036-8564, Japan.
• 2Department of Pathologic Analysis, Hirosaki University Graduate School of Health Sciences, 66-1 Hon-cho, Hirosaki, 036-8564, Japan.
• 3Department of Health Promotion, Hirosaki University Graduate School of Health Sciences, 66-1 Hon-cho, Hirosaki, 036-8564, Japan.
• 4Department of Disability and Health, Hirosaki University Graduate School of Health Sciences, 66-1, Hon-cho, Hirosaki, 036-8564, Japan.
• 5Faculty of Agriculture and Life Science, Hirosaki University, 3 Bunkyo-cho, Hirosaki, 036-8561, Japan.
• 6Center for Joint Research, Hirosaki University, 3 Bunkyo-cho, Hirosaki, 036-8561, Japan.
• 7Faculty of Education, Hirosaki University, 1 Bunkyo-cho, Hirosaki, 036-8560, Japan.

Abstract

SCOPE:

Blackcurrants (Ribes nigrum L., Grossulariaceae) contain high amounts of anthocyanin polyphenols, which have antioxidant and anti-carcinogenic health benefits. This study analyzed the potential phytoestrogenic effects of blackcurrant extract (BCE) in breast cancer (MCF-7) and human endometrial cancer (Ishikawa) cell lines that over-express estrogen receptor alpha (ERα), as well as in immature female rats.

METHODS AND RESULTS:

Microarray analysis and Ingenuity® Pathway Analysis showed that BCE activated the ERα pathway, whereas quantitative-PCR confirmed that BCE and four types of anthocyanins up-regulated genes downstream of ERα. BCE (0.1-1.0 μg/mL) and anthocyanins (0.1-10 μM) induced MCF-7 cell proliferation; however, this effect was blocked by ER antagonist fulvestrant.

Flow cytometry showed that anthocyanins reduced and increased the number of MCF-7 cells in the G0/G1 and G2/M phases, respectively.

Anthocyanins stimulated ERα transcriptional activity in human ERα reporter assays and induced alkaline phosphatase activity in Ishikawa cells. Competition assays and in silico analysis indicated that anthocyanins bind to ERα.

Finally, BCE focally induced stratification of columnar epithelial cells in the rat uterus and increased cytoplasmic mucin levels in these cells.

CONCLUSION:

These results suggest that blackcurrant anthocyanins act as phytoestrogens in vitro and in vivo. This article is protected by copyright. All rights reserved.

KEYWORDS:  Anthocyanin; Blackcurrant; Estrogenic activity; Phytoestrogen; Uterotrophic assay

PMID:  26395027