Inaugural Addresses (Biochemistry)

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Browsing Inaugural Addresses (Biochemistry) by Subject "Cyclopia"

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    I go to seek a great perhaps: the quest to obtain an approximate understanding of steriod hormone receptor signalling
    (2015-04) Louw, Ann
    Ann Louw (née Ramsay) was born on 30 March 1957 in Vereeniging, where she grew up until the age of 13 when her parents relocated to Mexico City. She started her schooling at Drie Riviere Laerskool and Drie Riviere Hoërskool in Vereeniging, continued it at the Greengates School in Mexico City and completed Grade 13 at Forest Hill Collegiate Institute in Toronto, Canada. She returned to South Africa for her tertiary education, completing her BSc with majors in biochemistry and physiology in 1977 and her BSc Honours in 1978 at Stellenbosch University, the alma mater of both her mother, Una Ramsay (BA in 1947), and her grandfather, Eben Dönges (BA in 1918, MA in 1919). She then continued studying towards her MSc in Biochemistry while working for the Research Department of the Western Province Blood Transfusion Service (1979–1985), completing the degree cum laude in 1984. She married her husband Albé in 1980. In 1986 her son Niel was born, and she needed some time to acclimatise to parenthood. Thus she accepted part-time employment: first as part-time technical officer in the Department of Medical Biochemistry at the University of Cape Town (1987–1988) and in 1988 as part-time technical officer in the Department of Biochemistry at Stellenbosch University, where she has remained ever since. In 1990, the year her second son, Ramsay, was born, she was appointed as lecturer in the Department of Biochemistry and continued her studies under the supervision of Prof Kirsten van der Merwe and Prof Pieter Swart, receiving her PhD in 1998, the year her daughter Una was born. She was promoted to senior lecturer in 1999, to associate professor in 2009 and to full professor in 2014. Prof Louw’s research focuses on signal transduction via steroid hormone receptors, specifically the glucocorticoid receptor (GR) and the oestrogen receptor (ER), which mediate the intracellular actions of the stress hormone cortisol and the sex hormone oestrogen, respectively. Recent work on the phytooestrogenic activity of Cyclopia or honeybush tea has highlighted ER subtype-specific signalling, indicating a potential use in breast cancer prevention or treatment, while recent work on the GR is focussing on the implications of loss or gain of dimerisation.
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    Selective extraction of Cyclopia for enhanced in vitro phytoestrogenicity
    (Stellenbosch : University of Stellenbosch, 2008-03) Mfenyana, Ciko; Louw, Ann; Joubert, Lizette; University of Stellenbosch. Faculty of Science. Dept. of Biochemistry.
    Phytoestrogens are plant compounds whose ability to mimic the action of estrogens has resulted in their usage for the treatment of menopausal symptoms. Despite uncertainties about the safety and effectiveness of phytoestrogens in humans, the use of market phytoestrogenic nutraceuticals and botanicals is on the increase. Positive epidemiological study findings coupled to an entrenched belief in many societies about the superiority of what they view as “natural” remedies, as well as the reluctance of women to use the traditional hormone replacement therapy due to its association with detrimental health effects as reported by studies such as the World Health Initiative, the Million Women and the Kronos Early Estrogen Prevention studies, are thought to be instrumental in the growth of the phytoestrogen market. As the subject of the current thesis, we investigated the candidacy of extracts of the honeybush plant (genus Cyclopia), which is used for the manufacture of popular tea beverages, for use in the formulation of a high quality phytoestrogenic nutraceutical with a competitive market edge. We evaluated four harvestings of Cyclopia (M6-9) available in bulk and selected 2 harvestings (M6 and M7) for further extraction using solvents of differing polarity and also mimicking the preparation of a cup of tea. Our findings clearly demonstrate that of the resultant 22 extracts the SM6Met and SM6EAc extracts had the highest in vitro potency and efficacy, respectively. Another exciting finding from our study is the unequivocal demonstration of phytoestrogenic activity by extracts prepared in the same manner as the traditional cup of honeybush tea. Additionally, our study has highlighted the importance and the influence of experimental variables such as the specific harvesting evaluated and the characteristics of the extraction solvent (e.g. polarity and temperature) on the yield and the estrogenic activity of the extracts. In addition, the advantage of certain in vitro assays over others for discriminating between estrogenic substances based on their efficacies and potencies was demonstrated with the alkaline phosphatase assay being most suitable for discriminating efficacy and the E-screen most suitable for discriminating potency. Furthermore, our study has imparted a valuable lesson about the pharmacological behavior of estrogenic substances by presenting a conundrum in the form of the two desirable pharmacological parameters (potency and efficacy) occurring in different extracts, an outcome that complicates the central aim of our study, which is the preparation of an extract that embodies both parameters. Additionally, the low quantity of known putative phytoestrogens and the presence of unidentified polyphenols in M6, the source of our choice extracts (SM6Met and SM6EAc), makes the high estrogenic potency and efficacy of the choice extracts that much more intriguing. Nonetheless, benchmarking against four market phytoestrogen extracts indicate that the Cyclopia extracts have comparable estrogenicity suggesting potential as marketable phytoestrogenic preparations. The combination of the achievement of aims and the birth of new questions from that very achievement, which are the hallmark of scientific endeavors, have made this study a rewarding experience and we hope to share the feeling in its entirety with the reader.