Evaluation of the phytoestrogenic activity of Cyclopia genistoides (honeybush) methanol extracts and relevant polyphenols

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dc.contributor.author Verhoog, Nicolette J. D.
dc.contributor.author Joubert, Elizabeth
dc.contributor.author Louw, Ann
dc.date.accessioned 2011-05-15T15:56:51Z
dc.date.available 2011-05-15T15:56:51Z
dc.date.issued 2007-04
dc.identifier.citation Verhoog, N. J. D., Joubert, E. & Louw, A. 2007. Evaluation of the phytoestrogenic activity of Cyclopia genistoides (honeybush) methanol extracts and relevant polyphenols. Journal of Agricultural and Food Chemistry, 55(11), 4371-4381, doi:10.1021/jf063588n.
dc.identifier.issn 0021-8561 (print)
dc.identifier.issn 1520-5118 (online)
dc.identifier.other doi:10.1021/jf063588n
dc.identifier.uri http://hdl.handle.net/10019.1/10079
dc.description The original publication is available at http://pubs.acs.org/
dc.description.abstract Unfermented C. genistoides methanol extracts of different harvestings and selected polyphenols were evaluated for phytoestrogenic activity by comparing binding to both ER subtypes, transactivation of an ERE-containing promoter reporter, proliferation of MCF-7-BUS and MDA-MB-231 breast cancer cells, and binding to SHBG. The extracts from one harvesting of C. genistoides (P104) bound to both ER subtypes. All extracts transactivated ERE-containing promoter reporters via ERβ but not via ERα. All extracts, except P122, caused proliferation of the estrogen-sensitive MCF-7-BUS cells. Proliferation of MCF-7-BUS cells was ER-dependent as ICI 182,780 reversed proliferation. Physiologically more relevant, extracts antagonized E2-induced MCF-7-BUS cell proliferation. Furthermore, all extracts, except P122, induced proliferation of the estrogen-insensitive MDA-MB-231 cells, suggesting that the extracts are able to induce ER-dependent and ER-independent cell proliferation. Binding to SHBG by extracts was also demonstrated. These results clearly show that C. genistoides methanol extracts display phytoestrogenic activity and act predominantly via ERβ. HPLC and LC-MS analysis, however, suggests that the observed phytoestrogenic activity cannot be ascribed to polyphenols known to be present in other Cyclopia species. © 2007 American Chemical Society.
dc.format.extent 11 p. : ill.
dc.language.iso en_ZA en_ZA
dc.publisher American Chemical Society
dc.subject Cyclopia en_ZA
dc.subject Phytoestrogens en_ZA
dc.subject Polyphenols en_ZA
dc.subject Functional foods -- Analysis en_ZA
dc.title Evaluation of the phytoestrogenic activity of Cyclopia genistoides (honeybush) methanol extracts and relevant polyphenols
dc.type Article
dc.description.version Publishers' version
dc.rights.holder American Chemical Society


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