Thesis submitted in fulfilment of the requirements for the degree DOCTOR TECHNOLOGIAE: ENGINEERING: CHEMICAL In the FACULTY OF ENGINEERING At the CAPE PENINSULA UNIVERSITY OF TECHNOLOGY 2009 / The white rot fungus, Phanerochaete chrysosporium strain BKMF-1767 (ATCC 24725), produces the extracellular enzymes, Lignin peroxidase (LiP) and Manganese peroxidase (MnP), that constitute the major route for lignin degradation by this organism. LiP and MnP have also been shown to play a major role in aromatic pollutant degradation. Due to the need for continuous production of LiP and MnP, a fixed-film bioreactor, classified as a membrane gradostat reactor (MGR), was developed. The implementation of batch-reactor operational parameters to the MGR system was found to be ineffective, thus creating the need for further research to improve the operational aspects of the MGR system to optimise its capabilities for continuous and industrial-scale operations. The research undertaken in this study, provides information that can be used to classify the dissolved oxygen (DO) transport kinetics into immobilised fixed-films of P. chrysosporium. Operational limitations of the MGR relating to environmental stresses in the bioreactor during operation and to biofilm deterioration, including limitations of DO mass transport, oxidative stress, trace element accumulation and polysaccharide storage in the fungal biomass, were evaluated in single capillary MGR systems (SCMGRs). These conditions were identified as existing in the continuous MGR systems. From DO profiles, the oxygen consumption and flux into the biofilms, including the distribution of DO, was determined to be dependent on the immobilised biofilm’s age. Younger biofilms showed higher DO distribution than older biofilms even when aeration was directed to the extracapillary space (ECS) of the reactor against the biofilm’s surface. An increase in anaerobic zone thickness was observed to be increasing with an increase in biofilm thickness. Although, DO kinetic parameters were comparable with those obtained in submerged mycelia pellets, higher oxygen consumption values were observed in biofilms grown in the SCMGRs. The limitations of MGR were identified as: 1) poor DO distribution in immobilised biofilms because of b-glucan production and storage in the immobilised biomass, resulting in ethanol production; 2) the peroxidation of lipids of the biofilms, which in turn will affect the long-term performance of the biomass caused by oxygenation and 3) trace element ion accumulation enhanced by b-glucan production. Furthermore, trace element ion accumulation was higher in the MGRs than in batch cultures using the same nutrient medium. The development of a perfluorocarbon (PFC) emulsion for the MGRs to counteract these limitations was investigated. The compatibility of the emulsion with oxygen-carrying capacity was shown with an improvement in biomass generation, LiP/MnP production and overall consumption of primary substrates, mainly glucose and ammonium tartrate, in batch cultures. The emulsions investigated were based on the addition of oxygen carriers: Perfluorooctyl bromide (PFOB), Bis-(Perfluorobutyl) ethene (PFBE) and Perfluoropropylamine (PFPA), using Pluronic F 68 (PF 68) as the surfactant. Concentrations of 10 to 30% (w/v) PFC and 8.5% (w/v) PF 68 were tested successfully in batch cultures. The emulsions containing 10% (w/v) PFCs resulted in improved biomass performance as opposed to emulsions with higher PFC oil concentrations. An emulsion containing 10% (w/v) PFOB was used to evaluate its efficacy in the SCMGRs, as the biomass yield and overall enzyme production were superior to PFPA and PFBE-based emulsions with similar oil concentrations. After successfully applying PFOB and PF 68 to the SCMGRs, the following results were obtained: 1) reduced ethanol production; 2) reduced trace element accumulation; 3) lower b-glucan production and 4) improved DO-penetration ratio in immobilised biofilms.

Thesis (DTech( Mechanical Engineering)-- Cape Peninsula University of Technology, 2014 / Magnetohydrodynamic (MHD) boundary layer flow of an electrically conducting viscous incompressible fluid with a convective surface boundary condition is frequently encountered in many industrial and technological applications such as extrusion of plastics in the manufacture of Rayon and Nylon, the cooling of reactors, purification of crude oil, textile industry, polymer technology, metallurgy, geothermal engineering, liquid metals and plasma flows, boundary layer control in aerodynamics and crystal growth etc. Nanofluid is envisioned to describe a fluid in which nanometer-sized particles are suspended in conventional heat transfer base fluids to improve their thermal physical properties. Nanoparticles are made from various materials, such as metals (Cu, Ag, Au, Al, Fe), oxide ceramics (Al2O3, CuO, TiO2), nitride ceramics (AlN, SiN), carbide ceramics (SiC, tiC), semiconductors, carbon nanotubes and composite materials such as alloyed nanoparticles or nanoparticle core–polymer shell composites. It is well known that, conventional heat transfer fluids, such as oil, water, and ethylene glycol, in general, have poor heat transfer properties compared to those of most solids. Nanofluids have enhanced thermophysical properties such as thermal conductivity; thermal diffusivity, viscosity and convective heat transfer coefficients compared with those of base fluids like oil or water. Owing to their enhanced properties, nanofluids can be used in a plethora of technical and biomedical applications such as nanofluid coolant: electronics cooling, vehicle cooling, transformer cooling, computers cooling and electronic devices cooling; medical applications: magnetic drug targeting, cancer therapy and safer surgery by cooling; process industries; materials and chemicals: detergency, food and drink, oil and gas, paper and printing and textiles.

A Thesis submitted in fulfilment of the degree Doctor Educationis Faculty of Education and Social Sciences Mowbray Campus Cape Peninsula University of Technology, 2012 / This thesis uses Reflective Topical Autobiography, as an adapted interpretation of narrative methodology, to investigate the influences on the construction of the identity of an art teacher‘s identity over time. The notion of human identity, and theorists who investigate this notion, initiates the study. The concept of teacher identity, and more specifically, art teacher identity, is explored. Teacher identity is acknowledged to be an integral part of the teaching and learning process, and so meaningful teaching, and more specifically, meaningful art teaching, is discussed. Questions that arise from this discussion provide the underpinning focus of the data analysis. What influences contribute to the construction of teacher identity? What role does knowledge play? What kinds of knowledge are important? How is that knowledge acquired? In this interpretive study, which is lodged in the qualitative paradigm of research, social constructionism provides a lens through which to investigate the life and the voice of an art teacher, as an interpretation of her professional identity construction. That life, and that voice, are my own. The purpose for this investigation is to attempt to trace the influences that construct the identity of an art teacher over an extended time, through reflecting on influential people, places and experiences in the educational and professional context,. Although I acknowledge that the personal and the professional are enmeshed, emphasis has been placed on the professional in order to invite greater reader resonance. Initially, an autobiography provides the broad data, from which incidents are selected that I believe have been important influences in the construction of my own teacher identity over time. Data analysis takes the form of further deep reflection on these incidents, in order to extract their significance and meaning. The methodology of Reflective Topical Autobiography is followed, reflecting on this carefully selected data, and these reflections are underpinned with a theoretical base. The construction of my own teacher identity over time is plotted, exploring significant educational and personal experiences that have contributed to making me the kind of teacher that I am. An attempt is made to extract principles of art teacher identity construction. The thesis concludes with recommendations for teacher education, in which my work is lodged, and with further recommendations to in-service teachers. This thesis uses the metaphor of a spiral, which is a process that begins at the centre, and moves outwards in a circular line. The reason for this choice is that reflection is a process that looks back, and with experience and new knowledge, enables one to come to a new understanding of the focus. The looking back, however, is from a different place on the spiral, and may in fact be from several different places on the spiral. Thus, the looking back, or reflection from a different place, offers a different perspective of the focus. Throughout the thesis, the poem Little Gidding, one of the Four Quartets, by T S Eliot (1942), is used and interpreted through the lens of this study. The use of artefacts, and in this case, photographs and mandalas that I have made over the years, offer a form of truth, a kind of substantiation for the written word. Education in South Africa has progressed through many years of difficulty, and amended or new curricula with various foci do not seem to address the problems appropriately. Perhaps a closer investigation of the identity of the teacher, and a stronger emphasis on nurturing this identity, will help to address some of the problems that seem to result in the poor preparation, for learners, for a meaningful place in the world beyond the classroom.

Thesis submitted in fulfillment for the requirements for the degree Doctor Technologiae: Environmental Health in the Faculty of Applied Sciences, Cape Peninsula University of Technology, 2012 / Water related issues such as water treatment and distribution have become extremely important all over the world due to population growth, growing urbanization, health and environmental pollutions. Contamination of water bodies especially in Africa with antibiotic resistant bacteria strains is a cause for concern. Escherichia coli O157 H:7, and various strains of non O157 E. coli and Acinetobacter spp. are known for antibiotic resistance. Both bacteria are environmental organisms found coexisting together with high potentials of exchange of resistance genes. Despite the stress conditions confronting these bacteria in water, food and the human body, in the form of disinfectants, antibiotics, salts and the innate immunity, they appear to develop adaptive mechanisms that enable them survive and cause infection. This therefore necessitates the need for investigation of effective virulence factor-targeted control measures. Culture of 62 water samples on Brilliance E. coli/coliform selective medium (BECSM, Oxoid), Eosin Methylene Blue (EMB) agar, or Baumann’s enrichment medium (BEM) and Leeds Acinetobacter Medium (LAM) for the isolation of E. coli and Acinetobacter spp. was carried out. Isolates were investigated for virulence factors, antibiotic resistance and transformation of resistance genes. The effect of oxidative stress exerted by 0.3% Crystal violet, 0.3% Bile salt, 4.0% NaCl, and 8% ethanol on some of the multi-drug resistant strains as well as the effect of stem back extracts of Curtisia dentata on verotoxin production by the verotoxic strains was also investigated. Out of the 69 isolates of E. coli (including O26:H11, O55, O111:NM, 72 O126, O44, O124, O96:H9, O103:H2, O145:NM and O145:H2.) and 41 isolates of Acinetobacter spp. with 26 (53.06%) of the E. coli and 6 (14.63%) of the A. haemolyticus isolates producing verotoxins, and no A. lwoffii isolate produced the toxins. Twenty five - 25(35.23%), 14(20.30%) and 28(40.58%) of the E. coli isolates were positive for VTx1&2, Vtx1 and Vtx2 respectively, 49(71.015%), were positive for extended-spectrum beta-lactamases (ESBLs), 7(77.78%) for serum resistance, 57(82.61%) for cell surface hydrophobicity, 48(69.57%) for gelatinase production and 37(53.62%) for haemolysin production. While transformation occurred among the E. coli and Acinetobacter isolates (transformation frequency: 13.3 x 10-7- 53.4-7), there was poor curing of the plasmid genes, a confirmation of presence of stable antibiotic resistant genes (DNA concentration between 42.7-123.8 μg) and intra-genetic transfer of multidrug resistant genes among isolates. Oxidative stress due to chemicals, salts, alcohol or freeze-thawing (blow temperature stress) exerted various degrees of lethality on E. coli isolates with some bacterial strains losing their potential to express virulence factors with time. There was however, generally insignificant (t test; P≤0.05) lethal effect against all the A. haemolyticus isolates, but crystal violet exerted the highest lethal effect on some individual isolates followed by ethanol, bile salt and NaCl. Isolates from wastewater demonstrated the highest rate of resistance compared to isolates from river water. The cell kill index (CKI) increased as temperature stress (-5; -18; and -28ºC) increased with time. But the rate of loss of expression of virulence factors or viability was slower in isolates from wastewater and abattoir compared to those from river water. Sixty percent of the E. coli isolates showed various levels of resistance to different antibiotics (ampicillin (10 μg), cefuroxime, cephalexin, ceftazidime and tetracycline (30 95 μg in each case)) (multidrug resistance index (MDRI) values 4.20-5.60%). Relative inhibition zone diameters (RIZD) of C. dentata extracts against E. coli serotypes ranged between 8-28% (MIC, 100-2500 μg/ml), while against A. lwoffii and A. haemolyiticus, the RIZD values ranged between 10-28% (MIC, 100-850 μg/ml) and 6-28% (MIC 150-2500 μg/ml) respectively. However, higher MICs (MIC, 70-2500 mg/ml) were recorded for isolates with high MDRI values. Extracts demonstrated inhibitory action against the expression of both Vtx1 and Vtx2 genes in E. coli, A. haemolyticus and A. lwoffii. Saponins, tannins, glycosides, anthraquinones, flavonoids, steroids, phenols quinones, anthocyanins, amines and carboxylic acids were present in C. dentata. Ethanol root bark extracts consistently showed the highest DPPH radical scavenging activity (62.43%), total phenol content (TPH) (57.62 26 mg GAE/g) and reducing power (RP) (41.32%), followed by those of the stem bark and leaf extracts with the respective values of 54.68%, 37.77 mg GAE/g and 21.83%. The extracts also induced the leakage of Na+ and K+ 107 ions from both test bacteria. Detection of virulence factors, antibiotic resistance genes and transformation among these isolates is a very significant outcome that will influence approaches to proactive preventive and control measures and future investigations. Resistant verotoxic A. haemolyticus could further complicate treatment in verotoxic food-borne or nosocomial infections. Induction of cationic leakage by extracts of C. dentata is an indication of one of its mechanism of action on bacterial cells. The plant can therefore be a good source of antibiotic substances for composition as antioxidants or antimicrobials with novel mechanism of action for the treatment of verotoxic bacterial infections.

Thesis submitted in fulfilment of the requirements for the degree Doctor of Technology: Mechanical Engineering in the Faculty of Engineering at the Cape Peninsula University of Technology, 2012 / Over the years, many organisations are constantly under extreme pressure for their survival and sustainability due to globalization, rapid pace of technological innovation and growing knowledge of their customers. Leaders within the Small and Medium Enterprises (SMEs) struggle in dealing with these pressures due to lack of management skills, market know-how, education and training, entrepreneurial drive, technological orientation, product distribution and networking, particularly when compared with large companies. Innovative culture becomes a major problem among these SMEs. This forces leaders to establish a sound environment where employees can be creative and innovative. However, innovative culture is relatively at a slow pace in South Africa compared with other countries. In an attempt to create an innovative environment for employees, many leaders introduced international based policies such as organisational restructuring and reengineering. Instead of these policies to ease the prevailing conditions, the stress levels within the workplaces elevated and crushed the little creativity left in them. Therefore, this study is undertaken to investigate the appropriate leadership style capable to spearhead the SMEs in instilling local based innovation culture for sustainability in the Western Cape, South Africa. A group of participants including both employees (n1=336) and leaders (n2=130) took part in the research survey within 50 SMEs in the Western Cape. Nevertheless, different sample sizes were utilised in various stages through different case studies. This study has adopted the survey research method for its reliability and being quantitative in nature originated from positivism paradigm. An innovative leadership model covered the key characteristics of leadership was developed to achieve the research objectives. All the characteristics as variables were formulated into propositions and hypotheses to determine the state of innovative culture in these SMEs. Cronbach's-Alpha coefficient was used for reliability test of all the characteristics. In addition, descriptive statistical results such as means, standard deviations, correlations, and Chi-Square were generated. The study results revealed that all leadership characteristics variables were found to have p values below (0.01) which suggested on the rejection of null hypotheses. From employees’ point of view, the results showed that the leaders lack inspirational and motivational and high gain risk-taking characters. Thus, employees were not satisfied with their management styles toward innovation. However, leaders rated themselves highly based on the responses. In essence, a mathematical model was also used to analyse the impact of innovative leadership on productivity and profitability. The research findings have confirmed that leadership has the ability to stimulate both productivity and profitability. The study results further indicated that innovative leadership contributed to low production costs that resulted in the increase of productivity and profitability. This study concluded that innovative leadership was vital to the innovative culture within SMEs. The proposed leadership model can be used as a guideline for SMEs to create innovative culture. Moreover, the mathematical model can be utilised for any SMEs to predict their productivity and profitability. ii The rest of the thesis is organized as follows: Chapter one emphasises on the research problems pointing out factors that affected leadership in South African SMEs. The importance of the SMEs in the economy of the country as well as their descriptions and definition of SMEs were discussed. The problem statement, research objectives, leadership definitions, research propositions were highlighted. A description of the proposed model was detailed, and finally, the significance of the study and ethical issues were addressed. Chapter two focused on improving new product development (NPD) through innovative leadership qualities. In this regard, the key factors bearing the impact on NPD such as lack of understanding customer needs, business skills and understanding of innovation in NPD. Chapter three discussed the impact of innovative leadership on organisational culture within SMEs in the Western Cape, South Africa. It outlined the key leadership characters such as visionary, passionate, charismatic, inspirational and motivational, immersed in progressive change, high gain risk taking, ability to network and fast and action oriented leadership, and how these characteristics influence leadership to create an innovative culture within SMEs. Chapter four highlighted how passionate and charismatic leadership impacted creativity and innovation within the SMEs. The leaders in these SMEs were passionate and charismatic. However, it is not sufficient to instill an innovative culture. Chapter five presents an approach on how to create an innovation culture through visionary leadership in the SMEs. The results revealed that employees were very satisfied with their leaders. However, the leaders needed to make more efforts in making employees to embrace their organisational vision in order to be competitive. Chapter six alluded on the developed mathematical model to analyse the impact of innovative leadership on organisational sustainability in terms of productivity and profitability. The mathematical model predicts how changes of innovative leaders influence the increase of profits while production costs decreasing. Chapter seven concluded the importance of innovation culture within the SMEs. This chapter also indicated that there is a tremendous lack of innovation drive within the leaders in the SMEs; such that employees are not motivated enough to bring new ideas that can add organisational values. The further study areas were highlighted as well. Keywords: Innovation, leadership, culture, new product development, sustainability and SMEs

Thesis (DTech (Mechanical Engineering))--Cape Peninsula University of Technology, 2013 / The flow of reactive viscous fluids in porous media presents a theoretically challenging problem and has a broad range of scientific, technological and engineering applications. Real life areas where such flow systems are encountered include drying of food, geothermal energy extraction, nuclear waste disposal, the flow of heat and fluid inside human organs, insulation of buildings, groundwater movement, oil and gas production, astrophysical plasmas, magnetohydrodynamic (MHD) pumps and generators, metal extraction and granulation of metals, aerospace and ship propulsion and automobile exhaust systems. The reactions within such flow systems are inherently exothermic. It is in this view that we carry out studies of thermal effects and thermal stability criteria for unsteady flows of reactive variable viscosity non-Newtonian fluids through saturated porous media. The study focuses on non-Newtonian fluids mainly because the majority of industrial fluids exhibit non-Newtonian character. Particular focus will be on fluids of the differential type exemplified by third grade fluid. Both analytical and numerical techniques were employed to solve the nonlinear partial differential equations that were derived from the conservation principles, namely the principles of conservation of mass, momentum and energy balance. Graphical representations were adopted in trying to explain the response of solutions to various flow parameter variations. In chapter 1 we defined important terms and expressions, laid down a summary of important applications, carried out literature survey, stated the statement of the problem, the aims and objectives of the study as well as an outline of the envisaged research methodology. Chapter 2 focuses on the derivations of the fundamental equations that derive the flow system. These are the continuity equation, the momentum equation and the energy equation. In chapter 3 we computationally investigated the unsteady flow of a reactive temperature dependent viscosity third grade fluid through a porous saturated medium with asymmetric convective boundary conditions. The response of velocity and temperature fields to each of the various flow parameters was analysed and interpreted. A transient increase in both the velocity and temperature profiles with an increase in the reaction strength, viscous heating and fluid viscosity parameter was observed. On the other hand, a transient decrease in the field properties was observed with increase in non-Newtonian character and the porous medium shape parameter. The reaction was noticed to blow-up if, depending on other flow parameters, the reaction strength is not carefully controlled.

Thesis submitted in fulfilment of the requirements for the degree Doctor of Technology: Design in the Faculty of Informatics and Design at the Cape Peninsula University of Technology 2013 / Digital drawing and animation, using basic computer software, opens up new possibilities in creative practice-­‐led research. The digital medium, with its relative ease of reproduction and storage of images, facilitates a reflective method of thinking-­‐while-­‐ drawing, thereby stimulating the creative process and providing a unique means of reflection-­‐in-­‐action. The computer’s ability to record images allows for temporal disruption, providing possibilities for exploring alternative creative solutions as well as retrospective, reflection-­‐on-­‐action. This thesis presents an interrogation of the researcher’s creative practice, as well as the findings and creative artefacts of other relevant practitioners in the field of digital drawing, animation, and related creative activities. A reflexive methodology was used to investigate the relationship between making, doing, and knowing in creative practice. The findings are supported by creative outputs (making), reflection on the creative process in relation to supporting literature (doing), and knowledge resulting from this reflection together with related theoretical research (knowing). The research revealed that digital drawing and animation supports new modes of making resulting in the production of original creative artefacts. It was further revealed that in relation to “doing”, the digital medium supports reflective practice by enabling the creative practitioner to document and reflect on these outputs both during and after making. The resulting reflexive actions combined with theoretical research lead to revelations concerning the relationship between thinking and drawing when using digital media as well as in a broader sense. The study thus contributes insights concerning art and design thinking, and makes a contribution to new developments in visual arts and design research. Practice-­‐led research introduces a theoretical paradigm that has methodological implications particularly in the context of the current re-­‐structuring and transformation of art and design education at South African Universities of Technology. The findings indicate that digital drawing and animation can encourage a critical and reflective approach not only in the work of creative practitioners by supporting new modes of making, but that it also has positive implications for visual arts research and teaching. In this regard the research highlights the need for promoting the integration of theory and practice in visual arts and design education curricula.

Thesis submitted in fulfilment of the requirements for the degree Doctor of Technology: Information Technology in the Faculty of Informatics and Design at the Cape Peninsula University of Technology, 2013 / During the last few years it has become evident that first-year undergraduate computer science programming learners in the Financial Information Systems (FIS) programme at the Cape Peninsula University of Technology (CPUT) in South Africa, encounter numerous barriers to successfully practice their programming skills, as well as to design, develop, test and electronically submit their computer science programming assignments. As a result, the formative and summative assessment marks of these learners over the past few years indicate a concerning downward trend year on year, a challenge with which most first-year learners find it difficult to come to terms with. This is primarily due to a plethora of obstacles that impede on learners' ability to complete and electronically submit their programming assignments, especially off-campus, as well as the inability to practice their programming skills outside the boundaries of the classroom. Upon investigation it was determined that this trend is primarily attributed to three major stumbling blocks, namely the limited availability of computers, the absence of the required software needed to complete programming assignments off-campus, and the limited availability of Internet access off-campus.

Thesis submitted in fulfilment of the requirements for the degree Doctor of Technology: Biomedical Technology In the Faculty of Health and Wellness Sciences At the CAPE PENINSULA UNIVERSITY OF TECHNOLOGY, 2012 / Oxidative stress and chronic (low-grade) inflammation are inseparably interconnected and both have been implicated in the aetiology of many disease states. The use of plant extracts for disease prevention and therapeutic purposes, is gaining more attention because of the health benefits of the bioactive phytochemicals in these extracts. This thesis reports on the antioxidant status, the oxidative stress modulation and anti-inflammatory properties of fermented rooibos (Aspalathus linearis) and red palm oil (RPO) from the oil palm plant (Elaeis guineensis) using a long-term and two short-term in vivo models. In the first (long-term) study, the effect of chronic feeding of rooibos, RPO or their combination on the endogenous antioxidant system was investigated. Data from this study provided:  The first scientific evidence that chronic feeding of rooibos, RPO or their combination for 22 weeks did not adversely affect the liver or kidney function parameters.  The first scientific evidence that chronic feeding of rooibos alone, or together with RPO for 22 weeks modulated the endogenous antioxidant system by inhibiting MDA formation and augmenting the reduced glutathione status.  The first scientific evidence of an additive or synergistic interaction in the ability of rooibos and RPO to modulate the endogenous antioxidant system. The second (short-term) study investigated the protective effects of rooibos, RPO or their combination on tert-butyl hydroperoxide (t-BHP)-induced oxidative hepatotoxicity, and results from this study provided:  The first evidence of the ability of the two extracts, either alone or in combination to protect against t-BHP induced hepatotoxicity. Supplementation of rooibos, RPO or their combination for eight weeks reversed the hepatic damage induced by t-BHP. The changes induced by t-BHP in the activities of catalase (CAT), superoxide dismutase (SOD), glutathione peroxidase (GPx) and glutathione reductase (GR) were reversed by these plant extracts. The extracts, supplemented alone or combined prevented lipid peroxidation as shown by the decreased levels of conjugated dienes iv (CD) and malondialdehyde (MDA) and reversed the t-BHP.-induced impairment of the glutathione redox status. The third (short-term) study provided the first scientific evidence of the in vivo anti-inflammatory properties of rooibos and RPO. The properties were demonstrated using a lipopolysaccharide (LPS)-induced hepatic endotoxemic model by:  Providing the first evidence of an additive or synergistic interaction in the ability of the combined rooibos extract and RPO supplementation to reverse LPS-induced hepatic damage.  Providing the first evidence for the modulation of the inflammatory responses by rooibos extract, RPO or their combination. Supplementation of rooibos extract, RPO or their combination for four weeks, modulated LPS-induced inflammatory responses by inhibiting the synthesis of pro-inflammatory cytokines, tumour necrosis factor-α (TNF-α) and interleukin-6 (IL-6).  Providing evidence that the observed anti-inflammatory effects of rooibos and RPO may be related to their ability to modulate oxidative stress. Supplementation of rooibos extract, RPO or their combination for four weeks, prevented hepatic lipid peroxidation induced by LPS by decreasing CD and MDA formation in the liver. Changes induced in the activities of antioxidant enzymes were reversed and the glutathione redox status was augmented. Based on these study results, it is proposed that the ability of rooibos and RPO to protect the liver, modulate endogenous antioxidant system and inhibit inflammatory responses may be associated with the unique combination of antioxidant phytochemicals in both plant extracts. The study suggested possible mechanism(s) for the observed health effects, and the development of rooibos and RPO as nutraceuticals, which may be beneficial in the prophylactic management of oxidant-induced liver injury.

Thesis submitted in fulfilment of the requirements for the Doctor of Technology: Biomedical Technology In the Faculty of Health and Wellness At the CAPE PENINSULA UNIVERSITY OF TECHNOLOGY, 2012 / Diabetes mellitus is a major health problem not only in urban, but also in the rural areas and is diagnosed by the presence of high glucose levels in the blood. Oxidative stress is known to be actively involved in the onset and progression of diabetes and its complications. Antioxidants have important roles in biological systems by scavenging free radicals which may result in oxidative damage of biological molecules such as lipids, proteins and DNA. Red palm oil, originally from the tropical area of Africa, generally consumed as cooking oil, is known to have some beneficial health effects due to the presence of lipid soluble antioxidants such as carotenoids, tocopherols and tocotrienols. It also contains almost an equal proportion of both saturated and unsaturated fatty acids which makes it distinctive from other vegetable oils. Rooibos, on the other hand, is grown in the Cederberg area of the Western Cape in South Africa and it is commonly consumed as a beverage. It contains a complex profile of water soluble antioxidants (flavonoids) and its health promoting potentials have been reported extensively. Some of the flavonoids present in rooibos include aspalathin, nothofagin, quercetin, rutin and orientin. The objective of this research project was to examine the potential beneficial effects of the dietary intake of red palm oil and rooibos on streptozotocin-induced hyperglycaemia and its influence on the antioxidant status and some biochemical parameters in male Wistar rats. The preliminary phase of this study was designed to investigate the biochemical effects of these two plant products at different dosages following consumption for a period of 7 weeks. The preliminary study did not reveal any adverse effects of the different dosages of red palm oil (1 ml, 2 ml and 4 ml) and rooibos (2%, 4% and 6%) on the experimental rats following dietary intake for 7 weeks. However, these natural products showed an improvement in the antioxidant status of the rats at the different doses. Using a single dose each of both plant products from the preliminary study, the main study was performed to investigate the influence of these two plant products singly and in combination on the blood and liver of streptozotocin-induced hyperglycaemic male Wistar rats. In the main study, streptozotocin (50 mg/kg) dissolved in 0.1 M citrate buffer (pH 4.5) through intramuscular injection was used for the induction of diabetes which was confirmed by the presence of high blood glucose after 72 hours. Red palm oil or rooibos extract alone did not have any effect on the control of blood glucose in the diabetic rats. The dietary intake of the combined treatment with red palm and rooibos had more health promoting effects on the diabetic rats which included a decrease in blood glucose, glycosylated haemoglobin, fructosamine and increased insulin levels. There was a marked increase in liver glycogen levels in all the diabetic groups. Treatment with rooibos alone showed a decrease in glycogen levels in the diabetic rats. The presence of liver enzymes in the serum, commonly used as indicators of liver damage was increased in all the diabetic rats. However, the combined treatment of diabetic rats with red palm oil and rooibos protected the liver from injury. Red palm oil improved high density lipoprotein cholesterol levels (HDL-cholesterol) in the diabetic rats. There was no effect on the activity of glucokinase, the first enzyme in the the glycolytic pathway in both the untreated and treated diabetic rats. However, the activity of pyruvate kinase, the last enzyme in the glycolytic pathway was reduced in all the diabetic groups. The combined treatment with both red palm and rooibos increased the activity of pyruvate kinase. Oxidative stress was confirmed in the diabetic rats with an increase in the plasma thiobarbituric acid reactive substances (TBARS), an indicator of lipid peroxidation. Treatment of diabetic rats with rooibos and the combination of red palm oil and rooibos brought plasma TBARS to a level that was not significantly different from the normal control group. There was a non-significant reduction of total glutathione in the non-treated and treated diabetic groups. A non-significant increase in the activity of liver catalase was observed in all the treated diabetic groups. The activity of superoxide dismutase was significantly decreased in the liver of diabetic rats. Diabetic rats treated with red palm oil, rooibos and the combined treatment showed an increased activity of superoxide dismutase in the liver. Red palm oil and the combined treatment increased the activity of glutathione peroxidase in both the red blood cells and liver of diabetic rats. Red palm oil, rooibos and their combined treatments also improved the plasma antioxidant capacity such as ferric reducing antioxidant power (FRAP) and oxygen reducing absorbance capacity (ORAC) in the diabetic rats. In conclusion, oxidative stress is actively involved in the progression of diabetes mellitus. Red palm oil and rooibos, most especially their combined treatment showed significant beneficial health promoting effects in the diabetic rats. The remarkable effects of the combined treatment of red palm oil and rooibos in the diabetic rats could be due to their antioxidant profiles. Based on the findings from this study, it can be adduced that these plant products could help in the management of diabetes and its complications and therefore, suggested the need for further research studies on antioxidant therapy in the management of diabetes mellitus.