<p>&nbsp / </p> <p align="left"><font face="Times New Roman">Aspalathus linearis (A. linearis), </font><font face="Times New Roman">commonly known as Rooibos tea or Red bush tea and </font><i><font face="Times New Roman">amellia sinensis (C. sinensis) </font></i><font face="Times New Roman">or Black tea are beverages that are consumed throughout the</font><font face="Times New Roman">world. These teas possess antioxidant, immunomodulating and anti-cancer actions. The aim</font> <font face="Times New Roman">of this study was to use <i>in vitro </i>assays to screen Rooibos and Black tea for endocrine</font> <font face="Times New Roman">modulation. </font><font face="Times New Roman">The immune modulating effects of Rooibos and Black tea were investigated using an <i>in vitro</i></font> <font face="Times New Roman">whole blood culture (WBC) assay. Unstimulated WBCs treated with Rooibos tea secreted</font> <font face="Times New Roman">higher levels of IL-6, IL-10 and IFN<font lang="JA">&gamma / </font>than cultures treated with DMSO control. Rooibos treatment of stimulated WBCs resulted in higher IL-6, lower IL-10 and no effect on IFN&gamma / </font><font face="Times New Roman">secretion compared to DMSO treated stimulated WBC. Black tea treatment of stimulated</font> <font face="Times New Roman">WBC resulted in decreased IL-6, IL-10 and IFN<font lang="JA">&gamma / </font>secretion compared to the DMSO treated</font> <font face="Times New Roman">stimulated WBC. </font><font face="Times New Roman">Extracts of Rooibos and Black tea were assessed for phytoestrogens using quantitative </font><font face="Times New Roman">estrogen ELISAs. Both teas contain phytoestrogens. The quantitative ELISAs showed that </font><font face="Times New Roman">Rooibos tea contained significantly lower estrone (E1), estradiol (E2) and estriol (E3) levels </font><font face="Times New Roman">than Black tea. The effects of Rooibos and Black tea on proliferation of the estrogen</font> <font face="Times New Roman">dependant MCF-7 cell line was determined to further characterise the phytoestrogenic</font> <font face="Times New Roman">properties of the teas. Both Rooibos and Black tea extracts caused a significant inhibition of</font> <font face="Times New Roman">MCF-7 proliferation. </font><font face="Times New Roman">This study shows that Rooibos tea and Black tea are beverages that can either stimulate or </font><font face="Times New Roman">suppress the immune system. Also, both teas contain significant levels of phytoestrogens as </font><font face="Times New Roman">determined by quantitative ELISAs. The current study confirms previous reports showing </font><font face="Times New Roman">inhibition of growth in breast cancer cell lines by phytoestrogens. The findings extend </font><font face="Times New Roman">related observations on the anti-carcinogenic potential of the two teas.</font></p>

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

Assignment (MPhil)--Stellenbosch University, 2000. / ENGLISH ABSTRACT: From 1954 to 1993 the Rooibos Control Board, a statutory one-channel marketing system, regulated the rooibos industry. In 1993 the industry was deregulated and competition between different role players in the industry emerged. In this study competitiveness is analysed from both a historical as well as a modem -day perspective. Modem economic theory defines that competition is good for all industry and that it leads to economic development. In the case of the rooibos industry, one could be inclined to think that the unique character of the product and the fact that the Control Board had established a marketing mechanism would limit competition and rivalry in the post -Control Board era. Inthis study it was determined that deregulation in this industry coincided with very intense price-driven rivalry in the export market whilst very little rivalry occurred in the domestic market. The information for this thesis was obtained from published Annual Reports of the Rooibos Control Board and from personal interviews with the main role players in the industry. Two strategies that could enhance the competitiveness of this industry are recommended: 1. Repositioning rooibos as a gourmet health tea. 2. Improving supply chain coordination within the industry. / AFRIKAANSE OPSOMMING: Verbetering van die Mededingendheid van die Rooibos Industrie Vanaf 1954 tot 1993 het die Rooibos Beheerraad, 'n statutêre enkelkanaal bemarkingsorganisasie, die rooibosindustrie gereguleer. In 1993 is die bedryf gedereguleer en kon mededinging tussen verskillende rolspelers plaasvind. In hierdie studie word mededinging uit beide 'n historiese sowel as moderne perspektiefbestudeer. Moderne ekonomiese teorie stel dit dat mededinging tot voordeel van alle industrieë is en dat dit lei tot ekonomiese ontwikkeling. In die geval van rooibos sou mens geneig wees om te dink dat die unieke karakter van die produk en die feit dat 'n bestaande bemarkingskanaal alreeds bestaan, mededinging sou beperk in die post-Beheerraad tydvak. In hierdie studie is bevind dat deregulering gepaard gegaan het met intense prys-gedrewe mededinging in die uitvoermark, terwyl die binnelandse mark bykans geen mededinging ervaar rue. Die inligting vir hierdie tesis is verkry uit gepubliseerde Jaarverslae van die Rooibos Beheerraad en deur persoonlike onderhoude wat gevoer is met rolspelers binne die bedryf Twee strategieë word voorgestel waarmee die bedryf meer mededingend gemaak kan word: 1. Produk herposisionering as 'n gourmet gesondheidstee. 2. Verbeterde koordinasie binne die voorsieningskettings.

Thesis (MSc)--Stellenbosch University, 2015. / ENGLISH ABSTRACT: This study describes: 1. Substrate binding assays investigating the effects of methanolic extracts of unfermented and fermented Rooibos on the binding of natural substrates to ovine adrenal microsomal and mitochondrial P450 enzymes, demonstrating the interference of substrate binding in the presence of the Rooibos extracts. 2. The effects of selected flavonoids (quercetin, rutin and aspalathin) on the binding of natural substrates to ovine adrenal microsomal and mitochondrial P450 enzymes, demonstrating interference of substrate binding in the presence of the flavonoid compounds. 3. Substrate conversion assays in non-steroidogenic COS-1 cells to investigate the effects of methanolic extracts of unfermented and fermented Rooibos on the activity of key steroidogenic P450 enzymes (CYP17A1, CYP21A2, CYP11B1, and CYP11B2), demonstrating inhibition of the catalytic activity in the presence of Rooibos extracts. 4. The effects of selected flavonoids on the substrate conversion of the aforementioned key steroidogenic enzymes expressed in COS-1 cells. 5. An investigation of the effect of methanolic extracts of unfermented and fermented Rooibos on steroid hormone production in human adrenal H295R cells under basal and stimulated conditions, demonstrating the modulating effects of unfermented and fermented Rooibos extracts. Basal and stimulated steroid hormone production was decreased in the presence of unfermented and fermented Rooibos. / AFRIKAANSE OPSOMMING: Hierdie studie beskryf: 1. Die gebruik van substraatbindings-essais om die effek van metanoliese ekstrakte, van gefermenteerde- en ongefermenteerde Rooibos, op die binding van die natuurlike substrate aan skaap adrenale mikrosomale en -mitochondriale P450 ensieme te bepaal. Daar is getoon dat die ekstrakte 'n beduidende inhiberende effek op ensiemsubstraatinteraksie gehad het. 2. Die die inhiberende effek van geselekteerde flavonoïede (kwersetien, rutien and aspalatien) op die binding van die natuurlike substrate aan skaap adrenale mikrosomale en -mitochondriale P450 ensieme. 3. Die gebruik van substraatomsettings-essais in nie-steroïedogeniese COS-1 selle, om die effek van gefermenteerde- en ongefermenteerde Rooibos ekstrakte op die aktiwiteit van die steroïedogeniese P450 ensieme (CYP17A1, CYP21A2, CYP11B1, and CYP11B2) se katalitiese aktiwiteit te bepaal. Daar kon aangetoon word dat die katalitise aktiwiteite van bg. ensieme beduidend beïnvloed word deur die Rooibos ekstrakte. 4. Die gebruik van substraatomsettings-essais in nie-steroïedogeniese COS-1 selle, om die effek van geselekteerde flavonoïede op die aktiwiteit van bogenoemde steroïedogeniese P450 ensieme te bepaal. 5. 'n Ondersoek na die invloed van metanoliese ekstrakte van gefermenteerde- en ongefermenteerde Rooibos op steroïedhormoon biosintese in die menslike adrenale H295R-selmodel. Die ondersoek, onder basale en gestimuleerde toestande, het getoon dat beide Rooibosekstrakte in bogenoemde toestande steroïedhormoon produksie geinhibeer het.

Thesis (MSc)--Stellenbosch University, 2015. / ENGLISH ABSTRACT: In this study, the influence of rooibos on the catalytic activity of enzymes 17β -hydroxysteroid dehydrogenase type 3 (17βHSD3), 17β-hydroxysteroid dehydrogenase type 5 (AKR1C3), 17β-hydroxysteroid dehydrogenase type 2 (17βHSD2), 5α-reductase type 1 (SRD5A1) and 5α-reductase type 2 (SRD5A2), which catalyse prostate androgen metabolism, was investigated. The activities of both 17βHSD3 and AKR1C3 heterologously expressed in CHO-K1 and HEK293 cells were inhibited significantly by rooibos, with rooibos reducing the conversion of androstenedione (A4) and 11keto-androstenedione (11KA4) to testosterone (T) and 11ketotestosterone (11KT), respectively. The catalytic activity of 17βHSD2 towards T, 11hydroxytestosterone (11OHT) and 11KT was also significantly inhibited by rooibos in transiently transfected HEK293 cells. In transiently transfected HEK293 cells rooibos did not inhibit SRD5A1 while the rate of T conversion to dihydrotestosterone (DHT) by SRD5A2 was decreased. Analysis of steroid metabolism in PNT2 cells also suggests that rooibos does not modulate the catalytic activity of endogenously expressed SRD5A towards A4, however, the conversion of T to DHT was reduced. In addition, reductive 17βHSD activity towards A4 was inhibited in the presence of rooibos in both PNT2 and BPH-1 cells. In contrast, the conversion of 11KA4 to 11KT was inhibited in BPH-1, PC-3 and LNCaP cells, with negligible conversion of 11KA4 in PNT2 cells. Interestingly, data suggests inhibition of 3α-hydroxysteroid dehydrogenase type 3 (AKR1C2) activity in the production of androsterone (AST) from 5α–androstenedione (5α-dione), as well as the dehydrogenase reaction of T to A4 in PNT2 cells by rooibos. Androgen metabolism pathways were subsequently investigated in LNCaP cells to determine androgen metabolism by endogenous enzymes. Rooibos resulted in the reduced conversion of A4 in LNCaP cells to the same extent as indomethacin, a known AKR1C3 inhibitor. Rooibos also modulated T, DHT and AST metabolism in LNCaP cells. Furthermore, uridine diphosphate glucuronosyltransferase (UGT) activity in LNCaP cells was inhibited by rooibos, decreasing T-, DHT– and AST-glucuronide formation. These data prompted subsequent investigations into the influence of rooibos at cellular level, and prostatespecific antigen (PSA) levels were assayed in the presence of rooibos. PSA was significantly inhibited by rooibos in the absence and presence of DHT, suggesting possible interaction of rooibos with the mutated androgen receptor (AR) or estrogen receptor-β (ERβ) expressed in LNCaP cells. Taken together, rooibos inhibited the catalytic activity of key enzymes that catalyse the activation of androgens in the prostate, as well as inhibiting enzymes involved in the conjugation of androgens. At cellular level, PSA levels were also decreased by rooibos, possibly through AR or ERβ interactions – clearly indicating a modulatory role for rooibos in active androgen production. / AFRIKAANSE OPSOMMING: In hierdie studie was die invloed van rooibos ten opsigte van die katalitiese aktiwiteite van die ensieme 17β-hidroksi-steroïed-dehidrogenase tipe 2, tipe 3 en tipe 5 (17βHSD2, 17βHSD3, AKR1C3), asook 5α-reduktase tipe 1 en tipe 2 (SRD5A1, SRD5A2) ondersoek. Hierdie ensieme is betrokke in die produksie van androgene in die prostaat. Rooibos het die katalitiese aktiwiteit van 17βHSD3 en AKR1C3 in CHO-K1 en HEK293 selle beïnvloed en het vermindere omskakeling van androstenedioon (A4) en 11keto-androstenedioon (11KA4) na testosteroon (T) en 11-ketotestosteroon (11KT), afsonderlik, veroorsaak. Die katalitiese aktiwiteit van 17βHSD2 teenoor T, 11-hidroksie-testosteroon (11OHT) en 11KT was ook beïnvloed in die teenwoordigheid van rooibos in HEK293 selle. Die katalitiese aktiwiteit van SRD5A1 teenoor A4 en T is nie beïnvloed deur rooibos nie, alhoewel dit voorkom asof rooibos die omsettingstempo van T na dihidrotestosteroon (DHT) deur SRD5A2, getransfekteer in HEK293 selle, verminder het. Verdere ondersoeke is in normale prostaat epiteel selle, in die teenwoordigheid van rooibos uitgevoer. Rooibos het geen invloed op die katalitiese aktiwiteit van SRD5A teenoor A4 gehad nie, alhoewel vermindere omskakeling van T na DHT aangetoon kon word. Rooibos het ook die omskakeling van A4 na T in beide PNT2 en BPH-1 selle tot „n mate geïnhibeer. Die omskakeling van 11KA4 na 11KT was ook verminder in BPH-1, PC-3 en LNCaP selle. Die omskakeling van 11KA4 na 11KT was beduidend laer in PNT2 selle en kon die invloed van rooibos nie aangetoon word nie. Bykomende data toon dat rooibos ook die omskakeling van 5α-androstenedioon (5α-dione) na androsteroon (AST), gekataliseer deur 3α-hidroksi-dehidrogenase tipe 3 (AKR1C2), verminder, gesamentlik met die vermindere omskakeling van T na A4, deur 17βHSD2, in PNT2 selle. Hierdie studie het ook ondersoek ingestel, na die metabolisme van androgene in LNCaP selle. Vermindere A4 metabolisme is in die teenwoordigheid van rooibos asook in die teenwoordigheid van indometasien, „n bekende AKR1C3 inhibitor, gevind. Rooibos verminder dus die aktiwiteit van reduktiewe 17βHSD in LNCaP selle. Verandering in die metabolisme van T, DHT en AST in LNCaP selle, in die teenwoordigheid van rooibos, is ook gevind. Verdere ondersoek in LNCaP selle het gewys dat rooibos „n vermindering in die produksie van gekonjugeerde T, DHT en AST veroorsaak. Die studie het die invloed van rooibos op prostaat-spesifieke antigeen (PSA) ook ondersoek. Daar is vasgestel dat rooibos die vlakke van PSA verminder in die afwesigheid en teenwoordigheid van DHT in LNCaP selle. Hierdie resultaat dui op moontlike interaksie van rooibos met die androgeen (AR) of estrogeen-reseptor-β (ERβ), teenwoordig in LNCaP selle. Rooibos het die katalitiese aktiwiteit van ensieme, wat bydra tot androgeen produksie, geïnhibeer, asook die konjugasie van androgene. Op „n sellulêre vlak, het rooibos die vlakke van PSA-sekresie verminder, wat moontlike interaksie met die AR en ERβ aandui. Hierdie bevindings dui daarop dat rooibos wel n rol het om te speel in die modulasie van aktiewe androgene in die prostaat.

Thesis (MTech (Consumer Science: Food and Nutrition))--Cape Peninsula University of Technology, 2011.Includes bibliographical references (leaves 139-156). / Oxidative stress has been implicated in the development of a number of chronic degenerative diseases. These diseases can often be prevented by dietary and lifestyle changes. One major dietary aspect is increasing the intake of plant foods, such as fruit and vegetables as they are rich in the major nutrient and nonnutrient antioxidants. The South African population does not have an adequate intake of fruit and vegetables and many barriers have been noted against increasing the intake of these foods. Other avenues should therefore be sought to increase the antioxidant intake. One such avenue is to use a basic food item consumed often as an antioxidant carrier to increase the antioxidant intake. Much interest has developed in functional foods and their therapeutic effects as well as the use of nutraceuticals in food product development and food fortification. Tea and its polyphenols, due to the antioxidant properties, is a potentially viable option for nutraceutical and functional food use. Rooibos and honeybush herbal teas, native to South Africa, can be potential nutraceutical sources to increase antioxidant levels of food due to their unique polyphenol content. The objective of the study was to increase the total antioxidant capacity (TAC) of a basic food item consumed regularly by most South Africans, such as brown bread through fluid manipulation using rooibos, honeybush and black teas respectively, as the replacement fluid for water in a standardised bread recipe formulation. The TAC of these experimental breads were compared to the TAC of the bread produced with no fluid manipulation (control bread) and a commercially processed bread (reference bread). The experimental breads were prepared using 2% weight per volume (w/v) and 5% (w/v) concentration levels for rooibos, honeybush and black tea respectively. To ascertain the TAC of the experimental breads, the fluorescein(FL)-based oxygen radical absorbance capacity (ORACFL) method was used. The hydrophilic (H)-ORACFL assay was used as the teas contain polyphenols which favour a water environment. The results indicated that the H-ORACFL of the control bread using water as the fluid and the commercial reference bread was significantly different (p < 0.05 for each) to all the experimental bread formulations besides for the 2% (w/v) honeybush experimental bread formulation. The 2% (w/v) honeybush experimental bread formulation was therefore not considered for the consumer acceptance testing. There was no significant difference (p > 0.05) in the H-ORACFL of the 2% (w/v) rooibos and black tea experimental bread formulations, but the H-ORACFL of the 5% (w/v) black tea experimental bread formulation was significantly (p < 0.05) higher than that of the 5% (w/v) rooibos experimental bread formulation. This particular experimental bread formulation had a “golden-orange” colour with a pungent smell due to the increase in rooibos concentration. The 5% (w/v) black tea experimental bread formulation, however, had noted negative sensory attributes of being densely textured with a very dark colour and a pungent and overpowering taste of black tea. These sensory attributes and TAC results lead to the rooibos experimental breads containing 5% (w/v) (as bread A) and 2% (w/v) (as bread B) chosen for the consumer acceptance testing and rooibos being a proudly South African product. The participants (n = 85) of the consumer acceptance testing participated voluntarily and were regular bread consumers. The sample was mostly female (57.6%), in the age group of 18 to 24 years (54.1%), with an education level of between three to four years post-matric/-grade 12 (71.7%) and single, living on their own without children (76.4%). They also represented a sample which had characteristics of a healthy lifestyle. Most participants perceived themselves as being of an optimal body weight (55.2%) and the majority was non-smokers (74.1%), physically active (63.5%), having no family history of chronic disease (69.4%) and not consuming dietary supplements (70.5%). Three sensory attributes of the experimental breads were rated for the acceptance testing and included appearance/colour, flavour/taste and texture/mouthfeel. Both the experimental bread formulations was accepted favourably regarding the above-mentioned sensory attributes. The three liking acceptance categories, ‘neither like nor dislike’ (neutral response), ‘like’ and ‘like very much’ were the most commonly indicated by the participants which also resulted in the experimental breads being rated as fair, good and very good according to the development scores. Although both breads were very similarly scored, there was a trend for bread A to be rated slightly higher regarding the above-mentioned sensory attributes. The acceptance category, ‘like’/good was scored the highest for bread A according to the sensory attributes of appearance/colour (56.5%), flavour/taste (55.3%) and texture/mouthfeel (50.6%). There was no significant association/difference (p > 0.05 for each) between the participants’ demographic characteristics and their overall acceptance of the experimental breads. Most of the participant biographic characteristics also had no significant (p > 0.05 for each) impact on the sensory attribute acceptance of the experimental breads. Although the majority (75%) of the participants consumed rooibos, there was no significant (p > 0.05) association/difference between the participants’ tea consumption and their acceptance of the experimental breads. Although most participants (64%) had no awareness of functional foods, most indicated willingness to purchase foods with added health benefits (93%) and to pay more for foods with added health benefits (73%). These results indicated a general acceptance of bread with functional food characteristics and the possibility of purchasing such products with added health benefits and even at a higher price premium.

Thesis (MScVoedselwet)--University of Stellenbosch, 2005. / Bibliography. Also available via the Internet.

Thesis (MTech(Biomedical Technology) -- Cape Peninsula University of Technology, 2010 / Defective sperm function is the most prevalent cause of male infertility. Mammalian sperm are rich in polyunsaturated fatty acids (PUFA) and are susceptible to attack by reactive oxygen species (ROS), an important mediator of sperm function. Normally, a balance is maintained between the amount of ROS produced and the antioxidant defense system. When an imbalance exists between ROS production and antioxidants protection in the favour of ROS activity, oxidative stress (OS) occurs which could lead to cellular damage. A shift in the levels of ROS towards pro-oxidation in semen can induce oxidative stress on sperm. This study compares the modulation of OS by an indigenous herbal tea (rooibos), Chinese green tea, commercial rooibos and green tea supplements in rat epididymal sperm and testicular function. Sixty male Wistar rats were supplemented with fermented or “green” rooibos, Chinese green tea, rooibos supplement, green tea supplement or water for ten weeks while inducing OS during the last two weeks. Rats consuming fermented rooibos and “green” rooibos showed a significant higher sperm concentration and motility. The superoxide dismutase (SOD) activity was significantly higher in the sperm of rats that consumed fermented rooibos, “green rooibos” and green tea compared to the control. Also, the superoxide dismutase activity of the groups that received fermented rooibos, rooibos supplement and green tea increased significantly in the testicular tissue compared to control. Catalase (CAT) activity in the epididymal sperm was significantly increased in the rats consuming fermented rooibos, “green rooibos” and both rooibos and green tea supplements compared to the control. None of the tea treatments showed a significant effect on catalase activity in the testicular tissue. A tendency to increase this activity was observed in fermented rooibos, green tea, rooibos and green tea supplements. The glutathione levels of rats fed with fermented rooibos and “green” rooibos were significantly higher in the rat epididymal sperm compared to the control while the glutathione level of rats consuming green tea supplement also increased significantly in the testicular tissue compared to the control. None of the tea treatments showed a significant effect on lipid peroxidation and ROS levels in the rat sperm. Although rooibos fermented, “green” rooibos and rooibos supplements showed a tendency to lower the levels of these biomarkers when compared with the control group in epididymal sperm. However, the rooibos supplement showed a significantly reduced ROS levels in the testicular tissue. In conclusion, our study demonstrated that rooibos extract and green tea are effective as antioxidants by increasing the antioxidant enzyme activities and glutathione levels in oxidative stress-induced rats and could offer a measure of protection against oxidative damage, thereby improving sperm quality and function.

Magister Scientiae (Medical Bioscience) - MSc(MBS) / Modulation of the male reproductive system occurs as a result of exposure to endocrine disrupting compounds (EDCs) in different life stages. The effects of EDCs on the male reproductive system include infertility, decreased sperm count, function and morphology, abnormal development of secondary sex characteristics, reproductive function and sexual behavior, as well as decreased libido. Phytochemicals are naturally occurring, biologically active chemical compounds in plants. They are divided into different groups. Isoflavonoids and lignans, are the two major groups of phytoestrogens. Phytoestrogens of teas, coffee and buchu have many beneficial effects on body systems such as antimutagenic, antidiabetic, anti-inflammatory, antibacterial and antiviral properties. They also elicit many adverse events, for example, heavy consumption of green and black tea may cause liver damage and added unwanted effects when combined with other herbal beverages. Chronic heavy consumption of coffee is positively correlated to acute myocardial infarction and can elevate serum cholesterol levels. Rooibos tea decreases steroidogenesis by steroid secreting cell lines.This study investigated the effects of these beverages on the male reproductive system, using a minced testes method for determination of cell viability and hormone (testosterone) production. The first objective of this study was to optimize protein supplement for in vitro testosterone production using human serum albumin (HSA) and foetal bovine serum (FBS). Testicular cultures were prepared and exposed overnight to different concentrations of both sera and then incubated for 4 hours with or without luteinizing hormone (LH). The results showed that addition of protein supplements (HSA or FBS) did not have a significant effect on testosterone production. The second objective of this study was to investigate the effects of green tea, black tea, rooibos tea, coffee and buchu on cell viability of testicular cultures. Cells were treated overnight with varying concentrations of the plant extracts followed by incubation with/without LH for 4 hours. The effects of the plant beverages on cellular protein production were determined by the Bradford assay. The results showed that treatment of cells with varying concentrations of the plant extracts (with/without LH-treatment) had no significant effect on total cellular protein. The third objective of this study was to investigate the effects of black, green and rooibos teas, coffee and buchu on testosterone production by testicular cultures. The results obtained from these experiments showed that rooibos tea and buchu did not affect testosterone production in the presence or absence of LH. The results also indicated that green tea, black tea and coffee inhibited testosterone production by mouse testis cultures in the presence of LH, but not in the absence of LH. Black tea was the most potent inhibitor of testosterone synthesis by mouse testis cultures (IC50= 48 μg/ml), followed by coffee (IC50= 64 μg/ml) and green tea (IC50= 173 μg/ml). Green tea, black tea and coffee inhibited LH-stimulated testosterone synthesis, suggesting that these beverages may impair testicular steroidogenesis in mice. Thus, in spite of their acclaimed beneficial effects, consumption of these beverages in high doses raises concerns for their inhibitory effects on male reproductive function. Further in vitro and in vivo studies are warranted to determine their exact mechanisms of action on the male reproductive system in general and testicular function in particular.

Thesis (MScAgric)--University of Stellenbosch, 2005. / ENGLISH ABSTRACT: Grey mould, caused by Botrytis cinerea, is the most important foliar disease of rooibos seedlings. Although the disease is primarily controlled with applications of fungicides, the improvement of cultural methods of disease management should lessen this dependence on chemical control. Such improvements would, however, not be possible without knowledge of the inoculum sources and dispersal of the pathogen. The aim of this study was to investigate the inoculum ecology of B. cinerea in rooibos nurseries in order to identify primary sources of inoculum and to improve the environmentally friendly management of the disease. The study was conducted in four nurseries over two production seasons (March to July 2003 and 2004). Levels of airborne inoculum of B. cinerea were monitored on a monthly basis inside and around the nurseries with spore traps. Samples of plant material and organic debris were taken in the corresponding areas to determine the incidence of plant material infected by the pathogen and the incidences of grey mould in the nurseries were recorded. Low numbers of B. cinerea colonies were observed on the spore traps. Similar levels of airborne inoculum were observed inside and around the nurseries. The incidence of plant material yielding B. cinerea was higher outside the nurseries than inside, indicating the importance of such materials as potential sources of inoculum. Since patterns of airborne inoculum observed in this study confirmed reports of the local dispersal of B. cinerea, the removal of possible hosts outside the nurseries could aid in the management of grey mould in rooibos nurseries. Resistance to dicarboximide fungicides is a genetically stable trait in B. cinerea, and therefore has the potential to be used as a phenotypic marker. This marker can be used to gain knowledge on the dispersal of B. cinerea inoculum inside and outside rooibos nurseries. Isolates of B. cinerea collected from the air and from plant material in and around four rooibos nurseries were assessed for resistance to iprodione at 1 and 3 μg/ml a.i. Some of the isolates showed resistance to iprodione at 1 μg/ml a.i. However, none of the isolates showed resistance at 3 μg/ml a.i. iprodione. The initial incidence of dicarboximide-resistance at the nurseries was slightly higher than expected. As the season progressed, the incidence of iprodione-resistant isolates decreased towards May, after which an increase was observed towards July. A relatively high percentage of isolates collected outside the nurseries was found to be dicarboximide-resistant. Two of the nurseries had a significant higher incidence of resistant isolates on plant material collected inside, than on plant material collected outside the nursery. However, when looking at resistance levels of airborne isolates, no significant differences were found in the incidence of resistant isolates sampled inside and outside the four nurseries. The data indicated the importance of organic debris and seed-borne infections in the survival and dispersal of dicarboximide-resistant isolates of the pathogen. With the current emphasis on organic agriculture the knowledge gained in this study presents valuable possibilities of improving the cultural management of grey mould in rooibos nurseries. / AFRIKAANSE OPSOMMING: Vaalvrot, veroorsaak deur Botrytis cinerea, is die belangrikste bo-grondse siekte van rooibossaailinge. Alhoewel die beheer van die siekte hoofsaaklik op die gebruik van fungisiede berus, behoort die verbetering van verbouingspraktyke hierdie afhanklikheid van chemiese beheer te verminder. Sulke verbeteringe sal egter slegs moontlik wees indien voldoende kennis van die inokulumbronne en verspreiding van die patogeen beskikbaar is. Die doel van hierdie ondersoek was om die inokulum ekologie van B. cinerea in rooibos kwekerye te ondersoek sodat primêre inokulumbronne opgespoor en omgewingsvriendelike siektebestuurspraktyke verbeter kan word. Die ondersoek is in vier kwekerye oor twee produksie seisoene (Maart tot Julie 2003 en 2004) uitgevoer. Vlakke van luggedraagde inokulum van B. cinerea is op ’n maandelikse basis met behulp van spoorvangers binne en buite die kwekerye gemonitor. Monsters van plantmateriaal en organiese materiaal is in ooreenstemmende areas geneem om die voorkoms van B. cinerea geïnfekteerde plantmateriaal vas te stel en die voorkoms van vaalvrot in die kwekerye is aangeteken. Min B. cinerea kolonies is op die spoorvangers waargeneem. Soortgelyke vlakke van luggedraagde inokulum is binne en buite die kwekerye waargeneem. Die hoër voorkoms van B. cinerea geïnfekteerde plantmateriaal buite die kwekerye as binne, dui op die belang van sulke materiaal as potensiële inokulumbronne. Aangesien die patrone van luggedraagde inokulum, soos waargeneem in hierdie ondersoek, ander berigte van B. cinerea se beperkte verspreidingsvermoë bevestig, kan die verwydering van moontlike alternatiewe gashere buite die kwekerye die bestuur van die siekte binne die kwekerye verbeter. Weerstand teen dikarboksimied fungisiede is ’n geneties-stabiele kenmerk in B. cinerea en het daarom potensiaal om as ’n fenotipiese merker gebruik te word. Hierdie merker kan gebruik word om kennis aangaande die verspreiding van B. cinerea in en om rooibos kwekerye in te samel. Botrytis cinerea isolate in lug en op plantmateriaal in en om vier rooibos kwekerye is gedurende 2003 en 2004 versamel. Die isolate is vir weerstandbiedendheid teen iprodioon by konsentrasies van 1 en 3 μg/ml aktiewe bestandeel (a.b.) getoets. Isolate met weerstand teen 1 μg/ml a.b. iprodioon is waargeneem, maar nie teen 3 μg/ml nie. Die aanvanklike voorkoms van dikarboksimiedweerstand by die kwekerye was hoër as verwag. Hierdie vlak het egter gedaal met die verloop van die seisoen tot in Mei, waarna ’n toename tot in Julie waargeneem is. Die persentasie dikarboksimied-weerstandbiedende isolate buite die kwekerye was relatief hoog. In twee van die kwekerye was die voorkoms van weerstandbiedende isolate op plantmateriaal in die kwekerye betekenisvol hoër as op plantmateriaal buite die kwekerye. Daar was egter geen betekenisvolle verskille in die voorkoms van luggedraagde weerstandbiedende isolate nie, ongeag van die kwekery of posisie. Die data dui op die belang van organiese materiaal en saadgedraagde infeksies in die oorlewing en verspreiding van dikarboksimied-weerstandbiedende isolate van die patogeen. Met die huidige klem op organiese landbou bied die inligting wat in hierdie ondersoek versamel is moontlike praktyke wat geïmplementeer kan word om die beheer van vaalvrot in kwekerye met behulp van verbouingspraktyke te verbeter.