Thesis (MScMedSc)--University of Stellenbosch, 2011. / ENGLISH ABSTRACT: Introduction: Athrixia phylicoides is an aromatic, indigenous shrub with high antioxidant content and numerous indigenous medicinal properties inferred by ingestion of an herbal brew of the plant. Commercialization of “bush tea” (derived from A. phylicoides) holds economic and developmental potential for indigenous communities provided the safety and efficacy of the herbal tea is established. Recently A. phylicoides has been shown by McGaw et al. (2007) to have similar antioxidant activity to Rooibos tea, and a unique, new flavonol (i.e. a polyphenolic antioxidant plant metabolite) 5-hydroxy-6,7,8,3′,4′,5′-hexamethoxyflavon-3-ol, unique to A. phylicoides, was isolated by Mashimbye et al. in 2006. With changes in the socio-economic climate and a new trend in merging Western lifestyle with traditional practices, new interest has been shown in herbal/natural remedies. Study Aim: The aim of this study was to firstly, determine the in vitro effect of A. phylicoides aqueous extract on glucose metabolism in cell lines that mimic the three key organs implicated in glucose homeostasis. Secondly, the study aimed to determine the potential ex vivo antioxidant and anti-inflammatory effect of the extract in pancreatic β-cells and peripheral mononuclear cells respectively. Methods: Leaves and fine twigs of A. phylicoides were processed into an aqueous extract. C2C12, Chang and 3T3-L1 cells were cultured under standard conditions and acutely exposed to increasing concentrations of extract and water vehicle, as well as 1 μM insulin and metformin as positive controls. Glucose uptake from 8 mM glucose culture media was determined using a fluorimetric oxidase method. Radioactive 14C-glucose oxidation to 14CO2 and determination of glycogen content of cells were used to assess the fate of intracellular glucose. RT-PCR was used to assess the extract effect on insulin-signalling gene expression. The antioxidative effect of A. phylicoides extract in pancreatic β-cells isolated from Wistar rats was determined by measuring nitric oxide (NO) production in response to hyperglycemic conditions. NO was labelled with diaminofluorocein diacetate and fluorescence was measured using flow cytometry. Insulin secretion of pancreatic β- cells was measured using radio-immuno assay. The anti-oxidative effect of the extract in lipopolysaccharide-stimulated peripheral mononuclear cells isolated from Wistar rats was determined by measuring the production of TNF-α using an ELISA kit. Results: C2C12 myocytes showed maximal increased glucose uptake at the 0.05 μg/μl extract concentration (228.3% ± 66.2, p<0.001). In Chang cells, A. phylicoides extract maximally increased the amount of glucose taken up at the 0.05 μg/μl concentration (134.5% ± 2.5, p<0.05). In 3T3-L1 cells, the extract maximally increased the amount of glucose taken up at the 0.025 μg/μl concentration (143.5% ± 10.3, p<0.001). An extract-induced increase in insulin receptor and glucose transporter four expression was seen in C2C12 myocytes. The oxidation of 14C-glucose to 14CO2 by C2C12 myocytes was maximally increased following acute exposure to the extract at 0.1 μg/μl (2919.3 fmol/1x10^6 cells ± 428, p<0.01). The oxidation of 14C-glucose to 14CO2 by Chang cells was maximally increased following acute exposure to extract at 0.1 μg/μl (4476.7 fmol/1x10^6 cells ± 1620, p<0.05); as seen in the C2C12 cells. A. phylicoides extract increased glycogen storage at all three concentrations tested in Chang cells, but maximally at the 0.025 μg/μl concentration (13.6 μg/1x10^6 cells ± 0.7, p<0.05). A. phylicoides extract did not have any measurable effect on the oxidative status of β-cells or the anti-inflammatory status of peripheral mononuclear cells. The extract did show an increase in first phase insulin secretion of β-cells in hyperglycemic conditions, although it was not significant. Conclusion: Athrixia phylicoides aqueous extract stimulates in vitro glucose uptake and metabolism in an insulin-mimetic manner, suggesting that this extract could potentially be beneficial to type two diabetics as an adjunct therapy. / AFRIKAANSE OPSOMMING: Inleiding: Athrixia phylicoides is 'n aromatiese, inheemse struik met 'n hoë antioksidant inhoud. Vele tradisionele medisinale eienskappe is gekoppel aan die ingestie van 'n kruie brousel van die plant, wat ook bekend as “bostee” is. Kommersialisering van “bostee” hou ekonomiese en ontwikkelings potensiaal in vir inheemse gemeenskappe mits die veiligheid en effektiwiteit van die kruietee bevestig kan word. McGaw et al. (2007) het onlangs bevind dat A. phylicoides se antioksidant aktiwiteit vergelykbaar is met die van rooibostee. 'n Unieke nuwe flavonol ('n polifenoliese antioksidant plant metaboliet) 5-hydroksie-6,7,8,3′,4′,5′-hexamethoksieflavon-3-ol, eie aan A. phylicoides, is deur Mashimbye et al. in 2006 geïsoleer. Met veranderings in die sosio-ekonomiese klimaat en 'n nuwe tendens om die westerse lewenstyl met tradisionele gebruike aan te vul word nuwe belangstelling in kruie/natuurlike rate ondervind. Studie Doelwitte: Die doelwitte van hierdie studie was eerstens om die in vitro effek van A. phylicoides waterekstrak op die glukosemetabolisme van drie sellyne wat die sleutel organe naboots wat glukosehomeostase beheer, te bepaal. Tweedens, is die potensiële ex vivo antioksidant en anti-inflammatoriese effek van die ekstrak op pankreatiese β-selle en perifere mononuklêere-selle onderskeidelik ondersoek. Metodes: n Waterige ekstrak is van die blare en fyn takkies van A. phylicoides berei. C2C12, Chang and 3T3-L1 selle is gekultuur onder standaard kondisies en akuut blootgestel aan stygende ekstrakkonsentrasies. Water het as kontrole gedien, met 1 μM insulien en metformien as positiewe kontroles. Glukose opname vanuit 8 mM glukose kultuurmedia is bepaal deur 'n fluorimetriese oksidase metode. Radioaktiewe 14C-glukose-oksidasie na 14CO2 en die bepaling van die glukogeen inhoud van selle is gebruik om die lot van intrasellulêre glukose te bepaal. RT-PKR is gebruik om die effek van die ekstrak op die insulien-seinpad geen-uitdrukking te ondersoek. Die antioksidant effek van A. phylicoides ekstrak in pankreatiese β-selle geïsoleer van Wistar rotte, is bepaal deur stikstofoksied (NO) produksie na aanleiding van hiperglukemiese kondisies. NO is met diaminofluorosien diasetaat gemerk en die fluoresensie gemeet deur vloeisitometrie. Insulien afskeiding deur die pankreatiese β-selle is deur radio-immuno metode bepaal. Die anti-oksidatiewe effek van die ekstrak op lipopolisakkaried-gestimuleerde perifere mononuklêere-selle afkomstig van Wistar rotte is bepaal deur die meting van TNF-α produksie met 'n ELISA kit. Resultate: C2C12 miosiete het 'n maksimale toename in glukoseopname by 'n 0.05 μg/μl ekstrakkonsentrasie (228.3% ± 66.2, p<0.001) gehad. Dieselfde ekstrakkonsentrasie het maksimale toename in glukoseopname in Chang selle (134.5% ± 2.5, p<0.05 getoon. In 3T3-L1 selle is maksimale toename in die glukoseopname by 'n konsentrasie van 0.025 μg/μl (143.5% ± 10.3, p<0.001) bereik. 'n Ekstrak-geinduseerde verhoging in die insulienreseptor en glukosetransporter vier ekspressie is in C2C12 miosiete waargeneem. Die oksidasie van 14C-glukose na 14CO2 deur C2C12 miosiete is maksimaal verhoog deur akute blootstelling aan die ekstrak by 'n konsentrasie van 0.1 μg/μl (2919.3 fmol/1x10^6 cells ± 428, p<0.01). Die oksidasie van 14C-glukose na 14CO2 deur Chang selle was maksimaal verhoog deur akute blootstelling aan die ekstrak by 'n konsentrasie van 0.1 μg/μl (4476.7 fmol/1x10^6 cells ± 1620, p<0.05) soos gevind in die C2C12 selle. Die ekstrak het glukogeenstoring verhoog teen al drie die konsentrasies waarteen getoets is in Chang selle, maar 'n maksimale effek is gevind by 'n konsentrasie van 0.025 (13.6 μg/1x10^6 cells ± 0.7, p<0.05). A. phylicoides ekstrak het nie 'n meetbare effek op die oksidatiewe status van β-selle of die anti-inflammatoriese status van perifere mononuklêere-selle gehad nie. Die ekstrak het wel 'n verhoging in die eerstefase insuliensekresie van β-selle in hyperglukemiese kondisies gehad, alhoewel die verhoging nie statisties betekenisvol was nie. Afleiding: Athrixia phylicoides waterekstrak stimuleer in vitro glukoseopname en metabolisme in 'n insulin-mimetiese manier, wat beteken dat die ekstrak potensiëel voordele vir tipe twee diabete kan inhou as aanvullingsterapie.

The most recent surveys in South Africa estimate that invasions are still increasing, despite substantial clearing efforts. Riparian systems in South Africa are particularly vulnerable to invasion by woody IAPs. This thesis addresses the restoration of alien‐invaded riparian systems, by investigating the factors that facilitate or constrain spontaneous recovery and influence the trajectories of succession. These factors include invasion history and management history, especially the use of fire. A seedling emergence approach was used to test the presence of a viable pre‐fire seedbank, and the effect of fire on the seed bank. The efficacy of some active restoration interventions was also tested, with the aim to return invasion‐resistant, indigenous vegetation with a structure and function representative of uninvaded sites. The findings of this study indicated the presence of a viable and persistent riparian soil seed bank, even after 30 years of intermtittent invasion as well as two fire cycles under invasion. It shows that the management practice of fell‐and‐burn resulted in high soil temperatures, and that this reduced the indigenous soil seed bank density, especially in the upper soil layer. Clear germination sequences and patterns of emergence over time for different species were observed during this study, with many species exhibiting delayed emergence relative to the timing of the fire event. It is proposed that manipulation of the season of fire could be used to selectively optimise the order of arrival and therefore superior recruitment of some species over others in the Eastern Cape fynbos, and thus alter the trajectories of recovery of vegetation towards a more desired state. Active restoration in the form of indigenous seed and plant additions resulted in a significantly higher indigenous cover after seven months, compared to a control (passive restoration) or restoring with grass. Indigenous cover and composition was also strongly influenced by lateral zonation, and some key guilds and species were missing or present in much lower densities compared to reference sites. Grass restoration significantly suppressed the regeneration of A. longifolia, as well as the regeneration of indigenous species. Biotic resistance can thus be achieved through restoration, and it could be a powerful tool in the management of IAPs, although the deliberate introduction of grass after clearing in fynbos also reduces biodiversity and could have unforeseen consequences to riparian function.

This work is a school-based case study conducted amongst learners of a rural High School and the immediate community in Whittlesea in the Eastern Cape where I teach. The research was conducted by using different research methods such as worksheets, questionnaires, interviews, practical activities and observations as well as photographs to investigate three indigenous wild local vegetable food plants (imifino). The fundamental assumption of the research is that, imifino can be looked after and cared for, to become valuable vegetable food plants which can be used as supplements to the cultivated vegetable food plants (umfuno). The question was: How could this concept be brought into the curriculum? It had also been assumed that bringing knowledge of imifino into curriculwn contexts could be of benefit to South African learners. The study produced a variety of findings: • There is a general feeling that those who eat imifino are the poor. • There is a lack of interest among women interviewed in the preparation process, for example going to pick the food plants from the fields, washing them and preparing the leaves as food. • AmaXhosa males look upon eating imifino with contempt. • Some males among the younger generation are beginning to overlook tradition and are eating imifino. • Inclusion of indigenous agricultural knowledge in the curriculum was supported by learners and community members. Learners have interest in knowing about indigenous food plants. • Learners feel as Africans that they must learn about the indigenous food plants in school in order not to lose knowledge of these plants completely. • The study also identified that interpretation of learning outcomes with an indigenous knowledge focus, requires careful attention to socio-cultural factors, and not just technical/ practical factors. Previous knowledge of learners and community members about imifino was mobilized to develop a sample OBE learning programme unit (LPU /Lesson plan) for the Grade 10 FET of Agricultural Science curriculum. The case study illustrates that Learning outcome 3 of the Agricultural Science subject can be achieved if educators involve learners and community members in developing learning programmes.

MSCAGR (Plant Production) / Department of Plant Production / Indigenous trees play important roles in livelihoods for rural communities. Sclerocarya birrea and Berchemia discolor are indigenous in Africa and are used in rural communities for food and livestock feed, as well as for medicinal and construction purposes. These trees are subject to attack by insects, which can result in lower tree productivity. However, there is no documented information about insects found on both tree species in South Africa. This study investigated the seasonal abundance and diversity of insects on S. birrea and B. discolor in Tshikundamalema Area, Limpopo Province, South Africa. Five trees were selected for each of the two tree species at two sampling sites with different vegetation cover, one site mainly the woodland bushveld while the other site was savannah grasslands. Canopy fogging was used to sample insects. Insect samples were collected at one time point for each of the seasons: summer (February), autumn (May), winter (July) and spring (November). Insects were identified to morphospecies and Simpson’s diversity index was used to compare insect diversity on both trees. Analysis of variance was used to compare the abundance of insects across seasons. The most abundant insects were collected from Coleoptera, followed by Hemiptera, Hymenoptera, Diptera, Lepidoptera and Orthoptera. A total of 3259 insects belonging to the six Orders were collected. All specimens belonging to Coleoptera, Hemiptera and Hymenoptera (3216 in total) were identified to Family level, with a total of 97 morphospecies, belonging to 19 Families. Insects from Diptera, Lepidoptera and Orthoptera were not identified further due to their low numbers. The abundance and diversity of insects were affected by seasons, sites and tree species. The number of insects was high during the spring season with 1782 insects, and summer coming second with 1104 individuals, followed by autumn (238 insects), then winter (92). B. discolor sampled for a great number of insects (1741) as compared to S. birrea (1475). The woodland bushveld (1924 insects) surpassed the savannah grassland (1292 insects) site in terms of the insect numbers sampled. / NRF

South Africa has over 19 500 different indigenous plant species. Most of these are of ethnobotanical significance and are still used by local rural communities as medicine, food and for making beverages. The relatively little research that has been conducted on indigenous plant species has focused mainly on their medicinal potential. However, in view of the rapidly growing size of the global and local beverage industry and their constant search for new products, beverage-making indigenous plant species may have commercial development potential. To date, no detailed studies have been conducted on these plants, especially in the species-rich Limpopo province. The aim of this study was, therefore to evaluate the potential of indigenous plants for commercial beverage production. In order to achieve this, a survey was conducted in the Limpopo province to identify beverage-making plants and to document beverage preparation methods. Selected beverages were analysed and evaluated for their nutrient and sensory characteristics and a market product acceptability survey was conducted to identify those beverages with the greatest potential for development. Sixty three different beverage-plant species were identified in three study areas within the Limpopo province. These were used for the preparation of teas, fruit juices and alcoholic beverages. Plants that received further research attention were selected on the basis of their status as indigenous plants, frequency of use, nature of harvesting methods and availability. Some of the selected beverages were found to be rich in nutrients, especially with respect to vitamin C and mineral content. Furthermore, sensory analyses and market surveys indicated that four species, namely, Doyvalis caffra, Garcinia livingstonei, Grewia flavescens and Englerophytum magalismontanum have potential for further development for the beverage industry while Athrixia phylicoides has commercialisation potential as a herbal tea. However, further research is required to improve and refine preparation methods and to ensure compliance with quality standards. The availability of sufficient plant material for the industry must also be ensured. This research has indicated that South African indigenous plants have untapped market potential for the beverage industry which, if developed sustainably, could contribute to economic growth of the rural parts of South Africa. / Environmental Sciences / D. Ed. (Environmental Management)

This study was conducted in Grahamstown in the Eastern Cape, South Africa. It is a qualitative case study located within the interpretive paradigm and was carried out over a period of a year. The theory implicit in the interpretive paradigm is of human beings as interpreters and constructors of a meaningful world. Thus, the focus of this study was on investigating the benefits of indigenous ways of knowing about wild food plants (imifino) in conjunction with hands-on activity-based lessons. This was done with the view to promote a conceptual understanding of nutrition and conservation in the Natural Sciences. The transformation of the school curriculum in South Africa called Curriculum 2005 (C2005) underpinned by the outcomes-based education (OBE) philosophy also triggered this study. The C2005 and OBE emphasise that learners’ prior everyday knowledge should be taken into account during the teaching and learning processes. The intention of the curriculum is to promote the idea of grounding knowledge in local contexts, while being sensitive to global imperatives. Although the acquisition of western knowledge has been and still is invaluable to all, on its own, it has been incapable of responding adequately to modern society in the face of massive and intensifying disparities, untrammeled exploitation of resources, and rapid depletion of the earth’s natural resources. Essentially, indigenous knowledge systems represent both a heritage and resource that should be protected, promoted, developed and, where appropriate, conserved. It is a resource that should serve the present and succeeding generations as many people’s cultural practices still rely on the use of wild plants. Within this context it should be borne in mind that the overexploitation of natural resources threatens not only biodiversity but also local traditional knowledge systems and ultimately cultural heritage; and research has a role to play in this regard. The research process in this study evolved into two main phases. The initial phase involved mobilising Grade 7 learners’ prior everyday knowledge on wild food plants (imifino). This led to the second phase of the research project, which was aimed at developing concepts through three hands-on activity-based lessons. I invited a community member to give a lesson on what imifino is and how to collect and prepare it, with the belief that the involvement of parents and community members in learners’ education can help bridge the gap between everyday life and school science. It is for these reasons that I believe that the constructive perspective can provide an appropriate methodological framework, conceptual structure and terminology for analysis of teaching and learning activities on the use of wild food plants in this study. The data generation techniques used in this study were questionnaires, observations and interviews (semi structured and focus group). A wide range of data generation techniques were employed to crystallise and validate the data generated using triangulation. The results from the analysed data revealed that consideration of indigenous ways of knowing in conjuction with hands-on practical activities enhanced interaction and learning among the learners. Also, linking of scientific knowledge to learners’ everyday lives was useful in fostering meaning-making and conceptual development.

South Africa has over 19 500 different indigenous plant species. Most of these are of ethnobotanical significance and are still used by local rural communities as medicine, food and for making beverages. The relatively little research that has been conducted on indigenous plant species has focused mainly on their medicinal potential. However, in view of the rapidly growing size of the global and local beverage industry and their constant search for new products, beverage-making indigenous plant species may have commercial development potential. To date, no detailed studies have been conducted on these plants, especially in the species-rich Limpopo province. The aim of this study was, therefore to evaluate the potential of indigenous plants for commercial beverage production. In order to achieve this, a survey was conducted in the Limpopo province to identify beverage-making plants and to document beverage preparation methods. Selected beverages were analysed and evaluated for their nutrient and sensory characteristics and a market product acceptability survey was conducted to identify those beverages with the greatest potential for development. Sixty three different beverage-plant species were identified in three study areas within the Limpopo province. These were used for the preparation of teas, fruit juices and alcoholic beverages. Plants that received further research attention were selected on the basis of their status as indigenous plants, frequency of use, nature of harvesting methods and availability. Some of the selected beverages were found to be rich in nutrients, especially with respect to vitamin C and mineral content. Furthermore, sensory analyses and market surveys indicated that four species, namely, Doyvalis caffra, Garcinia livingstonei, Grewia flavescens and Englerophytum magalismontanum have potential for further development for the beverage industry while Athrixia phylicoides has commercialisation potential as a herbal tea. However, further research is required to improve and refine preparation methods and to ensure compliance with quality standards. The availability of sufficient plant material for the industry must also be ensured. This research has indicated that South African indigenous plants have untapped market potential for the beverage industry which, if developed sustainably, could contribute to economic growth of the rural parts of South Africa. / Environmental Sciences / D. Ed. (Environmental Management)

Oldenburgia grandis is a rare, long-lived woody paleoendemic of the Fynbos Biome of South Africa. Confined to quartzite outcrops, it has a small geographic range and narrow habitat specificity. O. grandis responds to its fire-prone environment by resprouting. Elasticity analysis of O. grandis reveals that growth and fecundity were traded off for persistence of adult, mature and sapling stages. Morphological adaptations such as a corky fire-resistant bark and the ability to resprout after fire are traits that O. grandis have evolved to persist in a frequently disturbed environment. Population growth rate for sites undisturbed by fire for a number of years (l = 1.01) and sites at various stages of recovery after fire (l = 1.00) were very similar. The highest variation in transition probabilities for all sites was seen in the persistence of the seedling stage and growth from seedling to sapling. Observed population structure and stable stage distribution determined by the matrix model show that sites recently undisturbed by fire had high abundances of the adult and sapling stages. A peak in sapling stages was seen for the stable stage distribution where similar peak in sapling numbers were seen for population structures of sites at various stages of recoveryafter fire. Favourable environmental conditions for the persistence of O. grandis populations include no fire with transition probabilities between the observed minimum and maximum and fire frequency at a 10 year interval where seedling protection from the fire is high and adult and mature mortalities during the fire are low. Stochastic environmental events that could put populations (particularly small populations) at an increased risk of extinction include high to moderate fire intensities where seedling protection from the fire is low and adult and mature mortalities are high as a result of the fire.

MSCPNT / Department of Nutrition / Hypertension remains a major public health problem that needs different comprehensive health strategies to deal with it. Indigenous vegetables, Blackjack in particular, have been shown to possess anti-hypertensive properties that are attributed to bioactive chemical substances such as phytochemicals, fiber, antioxidants as well as micronutrients that include potassium, magnesium, calcium, vitamin C, zinc, iron and copper. The use of indigenous vegetables in combination with the conventional hypertension treatment may reduce hypertensive conditions; hence, the purpose of this study was to determine Blackjack nutritional knowledge and consumption by hypertensive patients. A cross-sectional study employing both quantitative and qualitative methods was conducted on 275 hypertensive participants at Mphambo and Mutale Health Centers, Vhembe District of Limpopo Province, South Africa. A questionnaire was used to collect data on participants’ Blackjack nutritional knowledge, Blackjack availability around their households as well as their Blackjack consumption patterns and nutritional status. The Blackjack nutritional knowledge data was triangulated with focus group discussions and participants’ nutritional status was assessed by anthropometric and dietary intake methods. The body mass index (BMI) was calculated and dietary intake frequency from selected foods was determined. Blood pressure was measured using Microlife automatic blood pressure monitor. The findings indicated that most hypertensive participants had poor knowledge of the nutritional importance of Blackjack and its associated medicinal contribution on hypertension management. Participants were unable to mention different diseases that can be prevented or managed by Blackjack, which was mostly consumed once a week with porridge during the summer season. Hypertensive patients were consuming high amounts of sodium and less amounts of minerals that are known to regulate blood pressure, such as potassium and magnesium. Hypertensive patients had high prevalence of overweight and obesity and most were either in hypertension stage 1 or stage 2. Lack of Blackjack nutritional knowledge may have contributed to a decreased consumption of Blackjack by hypertensive patients. The health professionals should promote the nutritional benefits of Blackjack in rural areas, particularly to hypertensive patients to raise awareness of Blackjack’s benefits in disease prevention and management. / NRF

This study focuses on the use of the Athrixia phylicoides plant in Tshwane, Gauteng, South Africa. The plant is used within the domestic domain as a beverage, for medicinal purposes, as well as for the manufacturing of domestic brooms. The aim of the study was to investigate the use and market of Athrixia phylicoides in two of the Tshwane markets, namely; Denneboom and Marabastad. Case study design, participant observation and interviews were employed to collect data. A literature review was conducted to construct a theoretical framework. The study reveals that traditional healers, broom makers and customers have a remarkable knowledge about Athrixia phylicoides, which has been untapped thus far. In addition, the study indicates that possible extinction of the Athrixia phylicoides plant, due to over-harvesting and lack of conservation, will pose a challenge to the market. / Anthropology / M.A. (Anthropology)