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

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dc.contributor.authorVerhoog, Nicolette J. D.en_ZA
dc.contributor.authorJoubert, Elizabethen_ZA
dc.contributor.authorLouw, Annen_ZA
dc.date.accessioned2011-05-15T15:56:51Z
dc.date.available2011-05-15T15:56:51Z
dc.date.issued2007-04
dc.descriptionThe original publication is available at http://pubs.acs.org/
dc.description.abstractUnfermented 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.description.versionPublishers' version
dc.format.extent11 p. : ill.
dc.identifier.citationVerhoog, 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.issn0021-8561 (print)
dc.identifier.issn1520-5118 (online)
dc.identifier.otherdoi:10.1021/jf063588n
dc.identifier.urihttp://hdl.handle.net/10019.1/10079
dc.language.isoen_ZAen_ZA
dc.publisherAmerican Chemical Society
dc.rights.holderAmerican Chemical Society
dc.subjectCyclopiaen_ZA
dc.subjectPhytoestrogensen_ZA
dc.subjectPolyphenolsen_ZA
dc.subjectFunctional foods -- Analysisen_ZA
dc.titleEvaluation of the phytoestrogenic activity of Cyclopia genistoides (honeybush) methanol extracts and relevant polyphenols
dc.typeArticle
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