Thesis (M.Ed. (Education)) - Rhodes University, 2009. / Submitted in partial fulfillment of the requirements for the degree of Master of Education.

Thesis (Ph. D.)--University of Hong Kong, 1999. / Includes bibliographical references.

Thesis (Ph. D.)--University of Missouri-Columbia, 2000. / Typescript. Vita. Includes bibliographical references (leaves 137-149). Also available on the Internet.

Thesis (Ph. D.)--University of Missouri-Columbia, 2000. / Typescript. Vita. Includes bibliographical references (leaves 137-149). Also available on the Internet.

Submitted in fulfillment for the Degree of Master of Technology (Biotechnology) in the Department of Biotechnology and Food Technology, Durban University of Technology, Durban, 2009. / Information regarding the nutritional value of wild food plants in Africa and current information varies from source to source. Prior to commercialization of wild foods the nutritional, ethnobotanical, medical, chemical, anthropological and toxicity requires investigation. Plants from the Amaranthaceae family were chosen because the family is characterized by several species which are used by indigenous communities as a source of nutrition in different plants of the world. The focus of this study was to investigate the nutritional and biological activities of three plants from the Amaranthaceae family viz. Achyranthes aspera, Alternanthera sessilis and Guilleminea densa that are considered famine plants. This study aimed to determine the nutritional value (proximate, minerals and vitamins), biological activity, toxicity and potential of a tissue culture system for three species from the family Amaranthaceae. Nutritional analysis comprised of determining moisture, ash, protein, fat, carbohydrate, dietary fibre and energy. Mineral analysis of calcium, copper, iron, magnesium, manganese, phosphorus, sodium and zinc was performed by microwave digestion and then analyzed by ICP Spectrophotometry. Vitamin A, Vitamin B1, Vitamin B2, Vitamin B3 and Vitamin C were also analyzed. For biological and safety analyses aqueous and methanolic extracts were prepared. Anti-oxidative and anti-inflammatory properties of the extracts were tested; antimicrobial activity was tested by evaluating the bactericidal, fungal effect and minimum inhibitory concentration on selected bacteria and fungi using the agar disk diffusion method. Anti mosquito potential was determined by setting up repellency, larvacidal assay and insecticidal assay. The safety and toxicity analysis was carried out by measuring cytotoxicity, toxicity and mutagenicity. The potential of an in vitro tissue culture system of A. aspera, A. sessilis and G. densa was determined using micropropagation. A. aspera indicated significant amounts moisture, ash, dietary fibre, protein, vitamin B1, vitamin B2, magnesium and manganese. Plant extracts of A. aspera had antibacterial activity against the Gram negative bacteria Esherichia coli, Pseudomas aeroginosa and Salmonella typhi; Gram positive bacteria Staphylococcus epidermis and Staphylococcus aureus. The methanolic extract had antifungal activity against Sacchromyces cerevisiae and exhibited significant free radical scavenging activity as well as 85% repellency against Anopheles arabiensis. The aqueous extract stimulated the growth of the K562 (Chronic Myclogenous Leukaemia) cell line and the plant extracts showed no mutagenicity or toxicity. A. sessilis indicated significant levels of ash, dietary fibre, protein, energy, vitamin A, vitamin B1, vitamin B2, vitamin B3, iron, magnesium and manganese present. Plant extracts of A. sessilis had antibacterial activity against Gram negative bacteria P. aeroginosa and Gram positive bacteria S. epidermis. The plant also showed antifungal activity against the yeasts S. cerevisiae and Candida albicans. The methanolic plant extract showed excellent antioxidant activity. The aqueous plant extract stimulated the growth of the K562 cell line and the plant extracts possessed no mutagenicity or toxicity. This plant grew well in a tissue culture system where it was propagated from callus to a fully grown plant able to survive in environmental conditions. G. densa has ash and dietary fibre, vitamin B2, vitamin B3 and iron. The plant extracts had antibacterial activity against Gram negative bacteria E. coli, P. aeroginosa and Klebsiella. oxytoca; Gram positive bacteria Baccilus stereathermophilus and S. aureus. The plant also has antifungal activity against C. albicans and significant repellency activity against A. arabiensis where it showed 100% repellency. This plant was not found to be mutagenic or toxic. The results obtained from this study show promising potential for the plants to be exploited as famine food plants. The nutritional value, biological activity and ability to micropropagate A. aspera, A. sessilis and G. densa indicates a good potential for purposes of harnessing biotechnological products.

Pitaya (Hylocereus peruvianus Backeb.) is an epiphytic wild cacti specie that grows in deciduous forests of northwestern Peru. It can be found in the district of Saña (Chiclayo-Lambayeque), Piura and Tumbes; however, they are not exploited in their natural state. The specie is considered a promising commercial crop due to its high nutritional value, medicinal properties and its elevated price in the national and international market. For people that are involved in this activity along the value chain, it may also improve their quality of life. Therefore, the cultivation and commercialization of pitaya is proposed as a strategy to create jobs, promote better consumption patterns and this, overall, improve the population’s quality of life in the district of Frias (Ayabaca-Piura) that will eventually lead to broader territorial development processes. / La pitaya (Hylocereus peruvianus Backeb.) es una especie de cactus epífito que se desarrolla de manera silvestre en el bosque deciduo del noroeste peruano. Puede ser encontrada en el distrito de Saña (Chiclayo-Lambayeque), Piura y Tumbes; sin embargo no es explotada en su estado natural. La especie es considerada un cultivo promisorio debido a su gran valor nutricional, propiedades medicinales y su alto precio en el mercado nacional e internacional siendo posible mejorar los niveles de calidad de vida de las poblaciones involucradas en esta actividad a lo largo de la cadena de valor. Por ello, se propone el cultivo y comercialización de pitaya como estrategia para generar empleo, mejorar los patrones de consumo y por lo tanto mejorar el nivel de calidad de vida de la población del distrito de Frías (Ayabaca-Piura) apoyando, de esta manera, procesos más amplios de desarrollo del territorio.

Cyclopia intermedia E. Mey is harvested from the wild to produce honeybush tea. The presence of a lignotuber and its slow growth seems to hinder the cultivation of this species and wild harvesting is likely to continue. Species distribution modelling indicated that C. intermedia has a climate envelope that spans from the Eastern Cape to the Western Cape along the Cape Fold mountains. This regional distribution is threatened under future climate change scenarios with a range loss and shift identified for climate conditions predicted for 2050. More specifically, its niche was identified as south-facing slopes with sandy to loamy sand soils and water holding capacity that is higher than the surrounding areas. Some keystone Fynbos species were found to share this niche: Leucadendron salignum, Leucospermum cuneiforme, Protea neriifolia, Protea repens, Elegia filacea and Rhodocoma fruticosa. Cyclopia intermedia grows throughout the summer with flowering buds developing in autumn. These enlarge during winter with the flowers opening in early spring. Pods develop in November and seed set occurs during December. Harvesting plants increases their fecundity with cut plants producing more than twice the number of pods and seeds compared to their non-harvested counterparts. This is because resprouting plants produce more flowering stems than uncut plants. Controlled harvesting or localised short-cycle burning could be considered as a management option to improve fecundity of declining Cyclopia intermedia populations in protected areas. C. intermedia harvesting could occur every third year and stem colour was identified as a measure of harvest maturity. Where at least 30 percent of the population has orange (RHS colour 163A) stems the population is suitable for harvesting.

Diss. (sammanfattning) Uppsala : Univ., 2001. / Härtill 5 uppsatser.

published_or_final_version / Ecology and Biodiversity / Doctoral / Doctor of Philosophy

The principal aim has been to investigate the contemporary role and importance of edible wild plants in the diets of women in different agro-ecological regions of Vietnam. Field studies were undertaken in four villages in the Mekong Delta (MD) and the Central Highlands (CH) in 1995-1999. Data collection included rapid appraisal techniques, botanical identification, dietary assessments (7-day food frequency recall), anthropometry, blood sampling (haemoglobin, serum ferritin, serum retinol and C-reactive protein) and analysis of vegetable samples (dry matter, selected minerals and vitamins, tannins and phytic acid). A food variety analysis was used to test the adequacy of diets. The uses of over 90 wild plant species were documented, many with multiple functions as foods, medicines and livestock feeds. In the dietary assessment 29 species were reported. Most women used a combination of home produced, commercial and wild vegetables. A high 72 and 43% respectively of the vegetables consumed in the MD and CH sites were gathered (rainy season). They contributed significantly to micronutrient intakes, especially vitamin A, calcium, vitamin C and folate. They added considerably to food diversity and women with the most diverse diets had relatively adequate nutrient intakes. The species used and importance of wild plants varied considerably with region, season and ethnicity. The main conclusions are that edible wild plants continue to make important contributions to the nutrient intakes of women. If this is neglected in diet assessments our understanding of the overall dietary adequacy may be misinterpreted and much valuable knowledge of traditional food diversification may be lost. A food variety analysis can be a useful tool in identifying groups with inadequate diets. The dual role of many species as dietary components and in preventive health care deserves greater attention.