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 (Biochemistry))--Stellenbosch University, 2008. / This study describes: 1. The preparation of chloroform, methanol and aqueous extracts of unfermented and fermented rooibos (Aspalathus linearis). 2. The chromatographic fractionation of aqueous rooibos extracts and an investigation into the polyphenol content and antioxidant activity of the fractions. 3. The preparation of ovine adrenal microsomes containing active steroidogenic P450 enzymes, including cytochrome P450 17a-hydroxylase, CYP17, and cytochrome P450 steroid 21-hydroxylase, CYP21. 4. An investigation into the influence of chloroform and methanol extracts of rooibos on the binding of steroid substrates, progesterone and 17-hydroxyprogesterone, to CYP17 and CYP21.

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) / The blood brain barrier (BBB) is a signaling interface between the blood and the central nervous system (CNS), which prohibits the entry of harmful blood-borne substances into the brain micro-environment, thus maintaining brain homeostasis. The crucial role of the BBB is protecting the CNS, which may adversely be affected by alcohol. The central component of the BBB, endothelial cells (ECs), regulates BBB transport by regulating the permeability both transcellularly and through their paracellular junctions, by structures called tight junctions (TJs) that are composed of proteins. The aim of this study was to investigate the in vitro effects of ethanol (EtOH) and fermented rooibos (Rf) on a monolayer of bEnd5 mouse brain ECs, by determining the effects of EtOH and Rf on bEnd5 (i) cell viability (ii) cell proliferation (iii) rate of cell division (iv) cell toxicity (v) claudin-5 transcription (vi) permeability across a monolayer of bEnd5 ECs and (vii) morphology, for a selected experimental timeline of 24, 48, 72, and 96hrs. We then investigated if the simultaneous exposure of Rf and EtOH could reverse or alleviate the EtOHinduced effects on the bEnd5 ECs. EtOH metabolism induces oxidative stress and results in a range of adverse physiological effects. Aspathalus linearis (rooibos) contains many phenolic compounds, of which the main antioxidant activity is attributed to aspalathin. Our underlining hypothesis is that the antioxidants in an aqueous rooibos extract may therefore protect against the potential oxidant damaging effects of alcohol on the BBB. Cells were exposed for 24hrs to selected concentrations of EtOH (25mM and 100mM), a concentration of Rf containing equivalent of 1.9nM aspalathin, and the combinations of EtOH and Rf. Cell viability and cell toxicity was determined, while cell proliferation and rate of cell division was estimated using the trypan blue exclusion assay. Real time quantitative PCR was implemented to quantify claudin-5 transcription, normalized against housekeeping genes, GAPDH and HPRT. Transepithelial electrical resistance (TEER) was measured using the Ohm Millicell-electrical resistance system, while bEnd5 monolayer morphology was analysed using the Zeiss scanning electron microscope. Both concentrations of EtOH led to an overall decrease in cell viability, and a decreased number of live cells across 72hrs. Consistent with this, EtOH resulted in increased cell toxicity across the 96hr experimental timeframe and a diminished rate of cell division. The transcription of claudin-5 in bEnd5 ECs exposed to 25mM and 100mM EtOH varied dramatically across the 96hr timeframe. While 25mM EtOH resulted in an overall decrease in TEER, cells exposed to 100mM EtOH only decreased TEER between 48 and 96hrs. Morphologically, both concentrations of EtOH led to compromised paracellular spaces as endorsed by high definition SEM analysis. The administration of Rf on its own resulted in an initial decrease in viability, followed by recovery between 72 and 96hrs. Exposure to Rf diminished live cell numbers at 72 and 96hrs, accompanied by a compromised rate of cell division and an overall increase in cell toxicity. In addition, Rf down-regulated claudin-5 transcription across the course of the experiment, particularly between 24 and 48hrs. In alignment with this, Rf also led to an increase in BBB permeability from 24 to 96hrs. However, SEM studies were not able to discriminate any differences between control and Rf treated cells. Our study showed that the BBB could be protected against the adverse effects of EtOH, and this at the plasma concentration induced by 500ml’s of Rooibos tea. The simultaneous exposure of Rf and EtOH was able to negate the effects of EtOH on cell viability, cell proliferation, and cell toxicity but exacerbated the effects of EtOH on claudin-5 transcription and paracellular permeability. Morphologically, co-exposure with Rf only reversed the effects of 25mM EtOH while exacerbating the effects of 100mM EtOH at 96hrs. In conclusion, EtOH was shown to be detrimental to the integrity of bEnd5 ECs, and the addition of a minuscule quantity of the Rf extract was able to partially alleviate excess ROS-induced effects.

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 (Master of Environmental Health)--Cape Peninsula University of Technology, 2020 / Background: The development of metabolic disease is accompanied by changes in gut microbiota phenotype, including a decrease of beneficial bacteria and increase of pernicious bacteria of the gastrointestinal tract. A Western (high-fat and high-sugar) diet, sedentary lifestyle and altered gut microbiota diversity have been associated with an increased risk of developing metabolic diseases such as type 2 diabetes and its associated risk factor, obesity. Many researchers have studied the link between the gut microbiota and diet. Hence our in vitro study is aimed at investigating the potential prebiotic effect of an aspalathin-rich unfermented rooibos extract, Afriplex GRT™ and aspalathin on the faecal bacterial diversity of vervet monkeys fed Western diet. Methodology: A total of six vervet monkeys (Chlorocebus pygerythrus) were selected from monkeys fed either a maize based normal diet (standard diet group; n=3) or a high fat diet (Western diet group; n=3) for more than 5-years. Faecal samples were collected from the animals in both groups at the Primate Unit and Delft Animal Centre (PUDAC) between 7 – 9 AM. Faecal samples from the two groups were divided into culture-independent baseline samples (before culture) and culture-dependent samples (after anaerobic culture). The culture-dependent samples were cultured under anaerobic conditions at 37°C for 10 hours, with or without Afriplex GRT™ extract or aspalathin. Bacterial genomic DNA (gDNA) was extracted from all samples using the NucleoSpin® DNA Stool extraction kit. Purified gDNA was sent for metagenomic sequencing for 16S rRNA gene analysis of microbial diversity using an Ion Torrent Next-generation Sequencing platform. Results: Results indicated that the Western diet affects the abundance of several bacterial species. Afriplex GRT™ and aspalathin significantly enhanced the relative abundance of health promoting butyrate-producing bacteria such as Faecalibacterium prausnitzii in both standard and Western diet groups (p= 0.02 and p=0.04, respectively). A similar trend was observed in other beneficial bacteria such as Eubacterium spp., Sutterella spp., and Dorea longicatena. Conclusion: Based on the data observed, it can be suggested that Afriplex GRT™ has a beneficial prebiotic effect on gut microbiota diversity and gut health.