A dissertation submitted to the Faculty of Health Sciences, University of the Witwatersrand, Johannesburg, in fulfilment of the requirements for the degree of Master in Pharmacy. Johannesburg, South Africa, 2006 / The aqueous extract of rooibos has been used for more than three hundred years since its discovery by the indigenous people. Currently, rooibos is gaining popularity in the cosmetic industry and incorporation of rooibos extracts in topical cosmetic formulations has become a fashionable trend. Both topical and intestinal absorption of rooibos tea were investigated. The transport of aspalathin in the unfennented (green) rooibos aqueous extracts and aqueous solution of pure aspalathin were studied. / IT2018

Thesis (MSc)--University of Stellenbosch, 2008. / Bibliography. Also available via the Internet.

Thesis (MTech (Biomedical Technology))--Cape Peninsula University of Technology, 2010 / Consumption of sucrose with a meal containing oxidised and oxidisable lipids cause an increase in oxidative stress which is referred to as postprandial oxidative stress. The modulating effect on postprandial oxidative stress by an antioxidant-rich beverage, fermented rooibos (Aspalathus linearis) was compared to that of a commercial soft drink (soda). Both study beverages contained sucrose and were consumed with a standardised fat meal. The study consisted of two parts, a pilot study (Phase One) where participants consumed either a standardised fat meal with water (control group n = 5) or a standardised fat meal with a sucrose-containing commercial soda (treatment group n = 8) using a parallel design, and the experimental study (Phase Two) where participants (n = 14) consumed the standardised fat meal with the commercial soda (control group) or the rooibos beverage (treatment group) using a crossover design. Specific analytical techniques and methods for determination of plasma glucose, serum insulin, lipid profile, an inflammatory indicator (high sensitive C-reactive protein), plasma antioxidant capacity, whole blood redox status and plasma lipid oxidation biomarkers were used. Results from the pilot study indicated significantly (P<0.05) higher postprandial levels of glucose in the control group at 4 hr and 6hr postprandially. The inflammatory biomarker and triglyceride levels were significantly (P<0.05) elevated in both groups when compared to their respective baselines. Results also showed the total antioxidant capacity and total glutathione levels in the plasma of both groups to be significantly (P<0.05) lowered when compared to the baseline values. The level of lipid oxidation biomarkers in the plasma was significantly (P<0.05) higher at 2 hr, 4 hr and 6 hr post time intervals for thiobarbituric acid reactive substances and 4 hr post time interval for conjugated dienes in the participants consuming the standardised fat meal with soda when compared to the baseline value, while this was reflected only at 2 hr post time interval for thiobarbituric acid reactive substances, with the conjugated dienes levels being significantly (P<0.05) lowered at 6 hr post time interval in the control group. No differences were shown on inter group level for the pilot study. On inter group level, results from Phase Two showed significant (P<0.05) lower levels of plasma glucose at 6 hr post time interval in the treatment group when compared to the control group, with insulin levels being significantly (P<0.05) higher in the control group at 4 hr post time interval.

>Magister Scientiae - MSc / The incidence of type 2 diabetes (T2D) is persistently increasing globally. T2D is associated with pancreatic β cell dysfunction and insulin resistance in peripheral tissues such as the liver and skeletal muscle. Skeletal muscle is the major site for insulin stimulated glucose uptake. Maintenance on a gestational high fat diet may programme insulin resistance. Programming is induced by the exposure of organisms to either a stimulus or insult during foetal and/or early neonatal life and alters offspring physiology and metabolism. The aim of the present study was therefore to investigate the effects of maternal diets, varying in fat content, on neonatal hepatic and skeletal muscle gene (mRNA) and protein (immunoreactivity) expression of proximal insulin signalling factors: insulin receptor alpha (IRα), insulin receptor substrate 2 (IRS2) and phosphoinositide 3-kinase-p110 alpha (PI3K-p110α), and to assess the therapeutic potential of Aspalathus linearis extract after high fat programming. Pregnant rats were randomised into groups maintained on diets with varying fat proportions: 10% (control), 20% (20F), 30% (30F) and 40% (40F) fat as energy throughout gestation. Neonatal liver and skeletal muscle were collected to determine the proximal insulin signalling expression profiles of the target factors: IRα, IRS2 and PI3K-p110α. Quantitative polymerase chain reaction (qPCR) was applied to determine mRNA expression of these target insulin signalling factors. Immunostaining of the target proteins in the liver and skeletal muscle was performed followed by relative quantification with image analysis software. Further, Aspalathus linearis (Al) extract was orally administered to mothers during gestation in the 10% (Control-Al) and 40% (HFD-Al) diets at a dose of 150 mg/kg. Body weight, food intake and blood glucose concentrations were monitored throughout gestation in mothers. Maternal diets, varying in the percentage of fat content, showed no significant effect on neonatal hepatic IR and IRS2 mRNA expression. However, hepatic PI3K mRNA expression was elevated in 30F neonates compared to 20F neonates. Skeletal muscle IR and PI3K mRNA expression were reduced in the 30F and 40F neonates compared to 20F neonates. There was reduced hepatic IRα immunoreactivity in 40F neonates compared to control and 20F neonates. Further, skeletal muscle IRα immunoreactivity was significantly reduced in 30F and 40F neonates compared to control neonates. Therefore foetal high fat programming reduced IRα in both the liver and skeletal muscle which may impair proximal insulin signalling in these glucose recipient organs. Aspalathus linearis had no effect on maternal serum insulin and glucagon concentrations. In addition, maternal caloric intake, body weight and organ weights (liver, brain and pancreas) were not altered amongst the groups. Further, HFD-Al neonates were heavier than control neonates. In conclusion, Aspalathus linearis, at a dose of 150 mg/kg, had neither harmful nor ameliorative effects in pregnant mothers fed high fat diet during gestation. In addition, Aspalathus linearis treatment had no ameliorative effects on neonates from mothers fed high fat diet throughout gestation.

Aspalathus linearis vorm deel van die Fabaceae familie. Die plant is n bladboudende, stikstofbindende naalddraer waarvan die naalde en dunner stingels geoes word vir bemarking as rooibostee. Die inbeemse plant, wat natuurlik in die Seder- en Olifantsrivierberge voorkom, word vandag reeds deur meer as 400 produsente kommersieel verbou. Die gewas word normaalweg verbou onder lae en wisselvallige reenval- en stremmende grondtoestande. Lae produksie is daarom een van die belangrikste knelpunte. Hiermee saam dra progressiewe terugsterwing by tot wisselende produksietendense. Hierdie situasie lei tot onstabiele markvoorsiening en het n beperkende uitwerking op die ontwikkeling van markte. Daar het dus n beboefte aan veral inligting oor die uitwerking van oespraktyke op produksie en terugsterwing asook basiese inligting oor aspekte van groei, koolbidraatreserwes en voedingselemente bestaan. Die doel van die buidige studie was dan ook daarop toegespits om bogenoemde inligting te bekom. Resultate verkry het daarop gedui dat die oes van rooibosteeplant die jaarlikse wegneem van 50 tot 60% van die droe massa van die bos bebels het, indien eenmalig geoes word. Oorblywende blaarmassa van plante wat op n konstante boogte gesny is, bet toegeneem met toenemende frekwensie van oes. Waar eenmalig, tweemalig of driemalig geoes is, was respektiewelik 5%, 21% of 52% van die totale blaarmassa voor oes aanwesig. Dit is duidelik dat groot boeveelbede fotosintetiserende materiaal asook droemassa met oes verwyder word. Resultate het getoon dat lengte- en massagroei van die oesbare gedeelte boofsaaklik tussen Augustus- en Meimaand plaasgevind het. co2 -opname het saam met die ontwikkeling van groei toegeneem gedurende die seisoen, totdat die volwasse blaar op n stadium as stoororgaan van koolbidrate begin funksioneer en fotosinteties blykbaar minder aktief geraak het. Die beste tyd van oes was wanneer die koolbidraatreserwes in alle bosdele relatief boog was. Indien te vroeg in die groeiseisoen geoes is, was verdwerging die meeste en terugsterwingsprobleme was groter as gedurende die midseisoen. Indien te laat gedurende die groeiseisoen geoes is, het daar nie weer bergroei voor die lente plaasgevind nie en die bos was onbedek, met groot wonde en laag in fisiologiese aktiwiteit gelaat. Dit skep moontlik ideale infeksietoestande vir swamme wat terugsterwing bevorder. Veldproewe het aangetoon dat die boogste produksie verkry is waar eenmalig tydens ongeveer Maartmaand geoes is. 'n Hoër frekwensie van oes het wel die leeftyd van rooibosteeplante aansienlik verleng, maar dit het nie opgeweeg teen die verliese in opbrengs nie. Daar word voorgestel dat bosse wat gedurende die periode geoes word, se naalde weer fotosinteties aktief is voor die dormante rusperiode en moontlik selfs tydens die winter. Hierdie aspek verdien verdere navorsing. Dit wil ook voorkom asof bosse wat later gedurende die groeiseisoen geoes word minder en vir korter periodes afhanklik van reserwes in die volgende vroeër lente was. Beide suiker- en styselreserwes kon egter dien as substrate vir energie en onderhoud van groei tot ongeveer Desembermaand. Uit resultate verkry is bereken dat 18,4 g N, 1,2 g P, 4,6 g K, 4,1 g Ca en 4,1 Mg benodig word vir elke 1 kg bemarkbare tee wat later in die groeiseisoen geproduseer is. Omdat die rooibosteeplant stikstofbindende knoppiesbakteriee bevat, beboort dit ten opsigte van N selfvoorsienend te wees. Daar word aanbeveel dat P, Ca en Mg met grondvoorbereiding reeds voorsien word vir die leeftyd van n aanplanting. K moet egter jaarliks toegedien word. / Thesis (DSc Agric)--University of Pretoria, 1987. / gm2015 / Agricultural Economics, Extension and Rural Development / Unrestricted

Thesis (MSc)--Stellenbosch University, 2012. / ENGLISH ABSTRACT: Damping-off of rooibos (Aspalathus linearis), which is an important indigenous crop in South Africa, causes serious losses in rooibos nurseries and is caused by a complex of pathogens of which oomycetes, mainly Pythium, are an important component. The management of damping-off in organic rooibos nurseries is problematic, since phenylamide fungicides may not be used. Therefore, alternative management strategies such as rotation crops, compost and biological control agents, must be investigated. The management of damping-off requires knowledge, which currently is lacking, of the Pythium species involved, and their pathogenicity towards rooibos and two nursery rotation crops (lupin and oats). Pythium species identification can be difficult since the genus is complex and consists of more than 120 species. Species identification is, however, greatly facilitated by analyses of the internal transcribed spacer (ITS) regions. These regions, have also been used to divide the genus into 11 phylogenetic clades (A to K), with some clades, such as clade G, still being poorly characterised. The first aim of the study was to characterize 12 Pythium clade G isolates that were obtained from damped-off rooibos seedlings, along with six known clade G species. Subsequently, oligonucleotides were designed for differentiating two rooibos associated groups that may represent new taxons, for future use in DNA macro-array analyses. Phylogenetic analyses of the ITS region and a combined phylogeny of four gene regions (ITS, -tubulin and, COX1 and COX2 [cytochrome c oxidase subunits I and II]) identified five sub-clades within Pythium clade G. The rooibos isolates formed two groups, Rooibos group I (RB I) and II (RB II) that clustered into two groups within sub-clade 1 with good support (64%-89% bootstrap, 1.00 probability). The Pythium RB I isolates had P. iwayamai as its nearest neighbour, and may represent a new species. The Pythium RB II isolates had P. canariense and P. violae as their closest relatives and may, along with other isolates contained in the RB II sub-clade, represent several new species. Morphological analyses of the rooibos isolates were inconclusive, since the isolates all contained similar morphological characteristics that did not correspond to the description of known Pythium species. The Pythium RB I and II isolates were all non-pathogenic toward rooibos, lupin and oats seedlings. For each of the two rooibos groups, one newly developed oligonucleotide was able to differentiate the isolates from clade G reference isolates using DNA macro-array analyses. The second aim of the study was to determine the oomycetes species associated with rooibos in nurseries and in a native rooibos site, and their pathogenicity towards rooibos and two nursery rotation crops (lupin and oats). Since some isolates were shown to be nonpathogenic, another aim was to determine whether these isolates, along with the previously characterised non-pathogenic Pythium RB I and RB II isolates, could suppress pathogenic oomycetes. Characterisation of isolates from 19 nurseries and one native rooibos site revealed the presence of five Pythium species (P. acanthicum, P. irregulare, P. mamillatum, P. myriotylum, and P. pyrilobum) and Phytophthora cinnamomi. In nurseries, P. irregulare was the most common species (81%) followed by P. myriotylum (14%). Similarly, P. irregulare was also the most prevalent species (57%) in native rooibos, but P. pyrilobum (26%) was second most prevalent. Pathogenicity studies on rooibos showed that all species, except P. acanthicum, were highly virulent causing 100% damping-off. On lupin, P. acanthicum was also the only non-pathogenic species, with the other species being less virulent on lupin than on rooibos. Only P. irregulare, P. myriotylum, and P. pyrilobum were pathogenic towards oats, and were also less virulent on oats than on rooibos. On lupin and oats, not all off the isolates from a specific species was pathogenic. Non-pathogenic Pythium species (P. acanthicum, Pythium RB I and II) was only effective at suppressing disease on the less susceptible crops of lupin and oats, but not on rooibos. The third aim of the study was to investigate the management of rooibos damping-off using two composts (A and B), and composts combined with non-pathogenic Pythium species. Evaluation of the suppression by composts of Ph. cinnamomi and 29 Pythium isolates, which represented the four pathogenic Pythium rooibos species, showed that both composts were able to suppress some, but not all of the pathogenic Pythium isolates. Both composts were very effective at, and the highest percentage control was achieved, with suppression of Ph. cinnamomi. Most isolates of P. mamillatum and P. pyrilobum were suppressed by composts, whereas most P. irregulare (> 62%) and P. myriotylum (>50%) isolates were not suppressed. Non-pathogenic Pythium species combined with either of the two composts were able to significantly reduce damping-off caused by P. irregulare or a combination of pathogenic species (P. irregulare, P. mamillatum, P. myriotylum, P. pyrilobum, and Ph. cinnamomi), compared to than when only the pathogens were present. In the absence of non-pathogenic species, neither of the composts was able to suppress the aforementioned pathogenic isolates. This study has improved our knowledge of the oomycete species that are involved in rooibos damping-off, and has identified possible management strategies for use in organic nurseries. Several oomycete species are involved in causing damping-off and their differential virulence, and responses to being suppressed by composts, will require the use of integrated management strategies. Management strategies that showed promise include the combined use of compost and non-pathogenic Pythium taxons. The use of oats, which is susceptible to fewer oomycete isolates than rooibos, could also be valuable as a rotation crop. Altogether, knowledge obtained in this study can be used to (i) optimize integrated management strategies for organic nurseries, (ii) elucidate the mechanisms involved in disease suppression and (ii) develop molecular techniques, such as DNA macro-arrays and quantitative PCR (qPCR) for the rapid assessment of the species involved, and the quantification of inoculum in nursery soils. / AFRIKAANSE OPSOMMING: Omvalsiekte van rooibos (Aspalathus linearis), wat ‘n belangrike inheemse gewas in Suid-Afrika is, veroorsaak ernstige verliese in rooiboskwekerye, en word deur ‘n kompleks van patogene veroorsaak, waarvan oömysete, hoofsaaklik Pythium, ’n belangrike komponent is. Die bestuur van omvalsiekte in organiese rooiboskwekerye is problematies, aangesien fenielamied fungisiedes nie gebruik mag word nie. Alternatiewe bestuurstrategieë, soos rotasie-gewasse, kompos en biologiese beheer-agente, moet dus ondersoek word. Die bestuur van omvalsiekte vereis kennis, wat tans ontbreek, naamlik die Pythium spesies wat betrokke is, hul patogenisiteit teenoor rooibos, en twee kwekery rotasie-gewasse (lupiene en hawer). Pythium spesie-identifikasie kan moeilik wees aangesien die genus kompleks is en uit meer as 120 spesies bestaan. Spesie-identifikasie word egter grootliks vergemaklik deur analise van die interne getranskribeerde spasieerder (ITS) areas. Hierdie areas is ook gebruik om die genus in 11 filogenetiese “clades” (A tot K) te verdeel, met sommige “clades”, soos “clade” G, wat steeds swak gekarakteriseer is. Die eerste doelwit van die studie was om 12 Pythium “clade” G isolate te karakteriseer, wat vanaf omvalsiekte rooibossaailinge verkry is, tesame met ses bekende “clade” G spesies. Gevolglik is oligonukleotiede ontwerp ten einde twee rooibosgeassosieerde groepe, wat nuwe taksons kan verteenwoordig, te onderskei, en vir toekomstige gebruik in DNS makro-“array” analise. Filogenetiese analise van die ITS area en ‘n gekombineerde filogenie van vier geen-areas (ITS, -tubulien en, COX1 en COX2 [sitokroom c oksidase sub-eenhede I en II]) het vyf sub-“clades” binne Pythium “clade” G geïdentifiseer. Die rooibos isolate het twee groepe gevorm, Rooibos groep I (RB I) en II (RB II) wat twee groepe binne sub-“clade” 1 gevorm het, met goeie ondersteuning (64%-89% “bootstrap”, 1.00 waarskynlikheid). Die Pythium RB I isolate het P. iwayamai as sy naaste verwant, en mag ‘n nuwe spesie verteenwoordig. Die Pythium RB II isolate het P. canariense en P. violae as hul naaste verwante en mag, tesame met ander isolate wat in die RB II sub-“clade” ingesluit word, verskeie nuwe spesies verteenwoordig. Morfologiese analise van die rooibos-isolate was onbeslis, aangesien die isolate almal soortgelyke morfologiese kenmerke bevat het, wat nie met die beskrywing van bekende Pythium spesies ooreengestem het nie. Die Pythium RB I en II isolate was almal nie-patogenies teenoor rooibos-, lupien- en hawersaailinge. Vir elk van die twee rooibosgroepe, was een nuut-ontwikkelde oligonukleotied in staat om die isolate van “clade” G verwysingsisolate te differensieer, deur die gebruik van DNS makro-“array” analise. Die tweede doelwit van die studie was om die oömysete spesies wat met rooibos in kwekerye en in ‘n inheemse rooibos-area geassosieer word, te bepaal, en hul patogenisiteit teenoor rooibos en twee kwekery rotasie-gewasse (lupien en hawer). Aangesien van die isolate nie-patogenies was, was ’n ander doelwit om te bepaal of hierdie isolate, tesame met die voorheen gekarakteriseerde nie-patogeniese Pythium RB I en RB II isolate, patogeniese oömysete kan onderdruk. Karakterisering van isolate van 19 kwekerye en een inheemse rooibos-area, het op die teenwoordigheid van vyf Pythium spesies (P. acanthicum, P. irregulare, P. mamillatum, P. myriotylum, en P. pyrilobum) en Phytophthora cinnamomi gedui. P. irregulare was die mees algemene spesie (81%) in kwekerye, gevolg deur P. myriotylum (14%). Soortgelyk was P. irregulare ook die mees algemene spesie (57%) in inheemse rooibos, maar P. pyrilobum (26%) was tweede mees algemeen. Patogenisiteitstudies op rooibos het getoon dat alle spesies, behalwe P. acanthicum, hoogs virulent was en 100% omvalsiekte veroorsaak het. Op lupien was P. acanthicum ook die enigste nie-patogeniese spesie, terwyl die ander spesies minder virulent op lupien as op rooibos was. Slegs P. irregulare, P. myriotylum en P. pyrilobum was patogenies teenoor hawer, en was ook minder virulent op hawer as op rooibos. Op lupien en hawer was nie alle isolate van ‘n spesifieke spesie patogenies nie. Nie-patogeniese Pythium spesies (P. acanthicum, Pythium RB I en II) was slegs effektief om siekte op die minder vatbare gewasse, lupien en hawer, te onderdruk, maar nie op rooibos nie. Die derde doelwit van die studie was om die bestuur van rooibos omvalsiekte te ondersoek, deur die gebruik van twee tipes kompos (A en B), en kompos gekombineer met nie-patogeniese Pythium spesies. Evaluasie van die onderdrukking deur kompos van Ph. cinnamomi en 29 Pythium isolate, wat die vier patogeniese Pythium rooibosspesies verteenwoordig het, het getoon dat beide tipes kompos in staat was om sommige, maar nie al die patogeniese Pythium isolate, te onderdruk nie. Beide tipes kompos was baie effektief, en die hoogste persentasie beheer was met die onderdrukking van Ph. cinnamomi verkry. Meeste isolate van P. mamillatum en P. pyrilobum is deur kompos onderdruk, terwyl meeste P. irregulare (> 62%) en P. myriotylum (>50%) isolate nie onderdruk is nie. Nie-patogeniese Pythium spesies, in kombinasie met enige van die twee tipes kompos, was in staat om betekenisvol omvalsiekte veroorsaak deur P. irregulare, of in ’n kombinasie met patogeniese spesies (P. irregulare, P. mamillatum, P. myriotylum, P. pyrilobum, en Ph. cinnamomi), te verminder, in vergelyking met wanneer slegs die patogene aanwesig was. In die afwesigheid van nie-patogeniese spesies, was nie een van die tipes kompos in staat om die voorafgenoemde patogeniese isolate te onderdruk nie. Hierdie studie het ons kennis rakende die oömysete spesies betrokke in rooibos omvalsiekte verbeter, en het moontlike bestuurstrategieë geïdentifiseer wat in organiese kwekerye gebruik kan word. Verskeie oömysete spesies is betrokke in die oorsaak van omvalsiekte, en hul verskille in virulensie, en reaksies op onderdrukking deur kompos, sal die gebruik van geïntegreerde bestuurstrategieë vereis. Bestuurstrategieë wat belofte toon, sluit die gekombineerde gebruik van kompos en nie-patogeniese Pythium taksons in. Die gebruik van hawer, wat vir minder oömysete isolate as rooibos vatbaar is, kan ook waardevol as ‘n rotasie-gewas wees. Tesame, kan kennis wat in die studie opgedoen is gebruik word om (i) geïntegreerde bestuurstrategieë vir organiese kwekerye te optimaliseer, (ii) die meganismes betrokke in siekte-onderdrukking te bepaal, en (iii) molekulêre tegnieke, soos DNS makro- “arrays” en kwantitatiewe PKR (qPKR) te ontwikkel vir die vinnige bepaling van die spesies betrokke, en die kwantifisering van inokulum in kwekery-gronde.

Philosophiae Doctor - PhD / South Africa (SA) is home to one of the six floral kingdoms of the world, and hosts a very diverse flora comprising an astonishing ~30,000 species. Herbal medicines play an important role in many of the diverse cultures of this country. Yet, agricultural production systems for most of these species are missing, and medicinal plants are usually collected in the wild. The endemic medicinal plants of SA produce a wide range of rare medicinally active compounds, which could be developed into drugs. Knowledge on the genes involved in the biosynthesis of these compounds could not only promote establishment of plant production systems, but also their biotechnological exploitation. Transcriptomics has been revolutionized by Next Generation Sequencing technologies, which can cost-efficiently provide a lot of information on plant genes and biosynthetic pathways. This thesis focuses on the establishment of methodologies for high-throughput plant transcriptome research, including: 1) harvesting plant material suitable for high-quality RNA analysis from distant locations, 2) high-throughput, and inexpensive biochemical sample screening, 3) extraction of high-quality RNA from recalcitrant, polysaccharide- and polyphenol rich plant material, and 4) biocomputational analysis of Illumina sequencing data, including quality control and pre-processing of data, de novo assembly of reads, protein prediction and functional transcriptome annotation. Rooibos (Aspalathus linearis) was chosen as the pilot plant, because it is one of the few indigenous SA medicinal plants that has been successfully cultivated as a commercial crop. It produces a wide range of phenolic compounds with health promoting properties (e.g. aspalathin and a phenylpropenoic acid glucoside with scientifically verified antidiabetic and cardioprotective effects). In the course of this study, seven rooibos transcriptomes were produced, assembled and functionally annotated, providing a first extensive dataset for identification of genes associated with economically important traits such as medicinal compound production, rooibos growth type characteristics and stress resistance.

Magister Scientiae (Medical Bioscience) - MSc(MBS) / The prostate is prone to three pathological processes that include inflammation, benign prostate hyperplasia (BPH) and tumors. According to the center for Disease and Control 1999-2012 report, prostate cancer is the second leading cause of death in the United States. Scientific evidence suggests that up to 30% of men in the general population aged from 50 years and above, irrespective of geographic origin, have foci of prostate neoplastic growth. Unbalanced ROS production and a dysregulated antioxidant defence system have been implicated in prostate cancer development. The transformation of a normal cell into cancer takes a very long period. This observation provides the advantage of using nutraceuticals to prevent, arrest or reverse the cellular and molecular processes of carcinogenesis. Based on scientifically observed positive health roles of green tea (Cameli sinensis) and rooibos (Aspalathus linearis) on major diseases like atherosclerosis, hepatitis and certain types of cancer, this thesis evaluated the effects of these two teas on benign (RPWE 1) and malignant (LNCaP) prostate cells. This was done through the quantification of reactive oxygen species (ROS) using a fluorescence dye 5,6 CM-H2DCFDA, total prostate specific antigen (PSA) levels using a PSA ELISA kit, cell viability using the MTT assay, apoptosis using Tali annexin V stain and cell imaging studies using a Zeiss axiovert 200M inverted fluorescence microscope. Statistical analysis was done using graphpad prism. The findings of this study show that aqueous extracts of green and black tea, fermented and unfermented rooibos and their active compounds epigallocatechin gallate (EGCG) and aspalatin, respectively, are cytotoxic in malignant (LNCaP) prostate cells but exert protective effects in benign (RPWE 1) prostate cells. This thesis implicates the pro-oxidant and anti-oxidant properties of the plant extracts, respectively, for the above mentioned effects. In this regard, tea and rooibos promoted ROS production in malignant (LNCaP) prostate cells, which subsequently promoted cell death of the malignant cells through apoptosis and necrosis. Further to this, tea and rooibos used in this thesis, protected normal prostate cells from the adverse effects of ROS. In this regard, fluorescence microscope photographs showed RPWE 1 cells with low DCF fluorescence compared to the malignant prostate cells. Low magnification light microscope photographs showed RPWE 1 cells with flat polygonal shapes and increased adherence both at low and high concentrations of tea and rooibos. On the contrary, high concentrations of tea and rooibos on malignant (LNCaP) prostate cells induced stress, which made the cells attain irregular shapes and as the stress levels increased, cells became detached and appeared dead. Flow cytometry confirmed the presence of apoptotic and necrotic cell in malignant (LNCaP) prostate cells. In this thesis, EGCG and aspalathin were responsible for the high rates of apoptosis observed whereas green tea and unfermented rooibos induced the highest rate of necrosis. Further to this, tea and rooibos and the main active compounds EGCG and aspalathin, respectively, significantly promoted the reduction of total serum prostate specific antigen (PSA) in malignant prostate cells. In normal prostate cells, these plant extracts maintained the total serum PSA at its basal physiological level. In this thesis, to the best of our knowledge, we report for the first time the cell-specific effects of fermented rooibos, unfermented rooibos and their main active component aspalathin, on prostate cancer cells. We showed that rooibos and aspalathin exert pro-oxidant effects on malignant LNCaP cells and anti-oxidant effects on benign RPWE 1 cells. In conclusion, tea (C. sinensis) and rooibos (A. linearis) and their respective main active compounds, epigallocatechin gallate and aspalathin, are cytotoxic to malignant prostate cells whereas in normal prostate cells, they have protective effects against ROS induced stress. The pro-oxidant and anti-oxidant effects are responsible for the aforementioned effects respectively. The decrease in total serum PSA demonstrate the strong therapeutic effects that tea and rooibos have on malignant (LNCaP) prostate cells. / Malawi Government: Department of Human Resources Development and Management

Magister Scientiae Dentium - MSc(Dent) / Candida albicans is a clinical fungal isolate that is most frequently isolated from different host niches, and is implicated in the pathogenesis of several fungal infections, including oral candidiasis. The pathogenesis and antifungal resistance mechanisms of Candida species are complex and involve several pathways and genes. Oral candidiasis incidence rates are rapidly increasing, and the increase in resistance to conventional antifungals has led to the need to develop innocuous and more efficacious treatment modalities. The purpose of this study was to explore a single pot process for phytosynthesis of zinc oxide nanoparticles (GZnO NPs) and to assess their antifungal potential.

Thesis (MSc (Biochemistry))--University of Stellenbosch, 2009. / This study: 1. Describes the preparation of unfermented and fermented rooibos methanol and aqueous extracts. 2. Investigates the influence of unfermented and fermented rooibos methanol and aqueous extracts on the binding of natural steroid substrates to ovine adrenal microsomal cytochrome P450 enzymes, demonstrating that the binding of natural steroids is inhibited in the presence of rooibos extracts. 3. Describes an assay demonstrating the inhibitory effect of rooibos extracts on the catalytic activity of cytochrome 17α-hydroxylase (CYP17) and cytochrome 21-hydroxylase (CYP21) in ovine adrenal microsomes. 4. Investigates the influence of unfermented and fermented rooibos methanol extracts on the catalytic activity of individual cytochrome P450 enzymes – CYP17 and baboon CYP21, that are expressed in COS1 cells. 5. Demonstrates that fractions of the unfermented rooibos methanol extract inhibits the binding of natural steroid substrate to microsomal cytochrome P450 enzymes as well as the catalytic activity of baboon CYP21 expressed in COS1 cells. 6. Investigates the inhibitory influence of individual rooibos flavonoids on the catalytic activity of baboon CYP21 expressed in COS1 cells.