Magister Scientiae - M.Sc. / Aspalathus linearis (A. linearis), commonly known as Rooibos tea or Red bush tea and Camellia sinensis (C. sinensis) or Black tea are beverages that are consumed throughout the
world. These teas possess antioxidant, immunomodulating and anti-cancer actions. The aim of this study was to use in vitro assays to screen Rooibos and Black tea for endocrine
modulation. The immune modulating effects of Rooibos and Black tea were investigated using an in vitro whole blood culture (WBC) assay. Unstimulated WBCs treated with Rooibos tea secreted higher levels of IL-6, IL-10 and IFNγ than cultures treated with DMSO control. Rooibos treatment of stimulated WBCs resulted in higher IL-6, lower IL-10 and no effect on IFNγ secretion compared to DMSO treated stimulated WBC. Black tea treatment of stimulated WBC resulted in decreased IL-6, IL-10 and IFNγ secretion compared to the DMSO treated stimulated WBC. Extracts of Rooibos and Black tea were assessed for phytoestrogens using quantitative estrogen ELISAs. Both teas contain phytoestrogens. The quantitative ELISAs showed that
Rooibos tea contained significantly lower estrone (E1), estradiol (E2) and estriol (E3) levels than Black tea. The effects of Rooibos and Black tea on proliferation of the estrogen dependant MCF-7 cell line was determined to further characterise the phytoestrogenic properties of the teas. Both Rooibos and Black tea extracts caused a significant inhibition of MCF-7 proliferation. This study shows that Rooibos tea and Black tea are beverages that can either stimulate or suppress the immune system. Also, both teas contain significant levels of phytoestrogens as determined by quantitative ELISAs. The current study confirms previous reports showing inhibition of growth in breast cancer cell lines by phytoestrogens. The findings extend related observations on the anti-carcinogenic potential of the two teas. / South Africa
| Identifer | oai:union.ndltd.org:netd.ac.za/oai:union.ndltd.org:uwc/oai:etd.uwc.ac.za:11394/2863 |
| Date | January 2008 |
| Creators | Hendricks, Rahzia |
| Contributors | Pool, Edmund J., Faculty of Science |
| Publisher | University of the Western Cape |
| Source Sets | South African National ETD Portal |
| Language | English |
| Detected Language | English |
| Type | Thesis |
| Rights | University of the Western Cape |
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