Magister Scientiae - MSc / This study aimed to evaluate the antimicrobial efficacy of medicinal hemp plant extracts to determine the antibacterial effects of indigenous Sansevieria species and exotic Cannabis sativa phytotherapy varieties. This study also assessed whether aqueous o / South Africa

Magister Pharmaceuticae - MPharm / Leonotis leonorus and Mentha longifolia are two herbs commonly used in South Africa, mostly in oral liquid dosage forms. Several disadvantages are associated with these traditional dosage forms which can perhaps be remedied by using an appropriate oral solid dosage form, provided the actual plant material in the latter still resemble, as closely as possible, the traditionally used material and provide products of suitable pharmaceutical quality. The objectives of this study were to prepare and evaluate the pharmaceutical suitability of the freeze-dried aqueous extracts of Leonotis Leonorus and Mentha Longifolia as plant raw material for the capsule dosage of these two therapies and to formulate and manufacture capsules of Leonotis Leonorus and Mentha Longifolia aqueous extract that would contain amounts of the plant materials equivalent to that found in their traditional liquid dosage forms, and have immediate release characteristics and suitability stability. / South Africa

Magister Scientiae - MSc / The incidence of cardiovascular diseases, including hypertension, is on the increase worldwide. Medicinal plants played an important role in the treatment of hypertension for centuries. Very few scientific studies have, however, been done to validate the use of these phytotherapies. O africana is on of the many phytotherapies that has been use indigenously for years to treat hypertension. The objectives of this study were to determine the most effective does of O africana aqueous extract which will reduce blood pressure; to determine whether chronic administration of O africana can be used to prevent and treat hypertension; to determine whether O africana exert its effects by modulation of the renin-angiotensin system. / South Africa

Malaria continues to be a major cause of mortality and morbidity especially in Sub-Saharan Africa. The emergence and spread of drug resistant parasites has highlighted the need for new chemically diverse, effective drugs. Historically, one of the major sources of antimalarial agents and novel template compounds has been higher order plants. The widespread use of medicinal plants for the treatment of malaria in South Africa represents a diverse resource of potential antimalarial drugs. Two South African plants, Vernonia staehelinoides and Oncosiphon piluliferum, were identified as potential sources of new antimalarial drugs through a national multidisciplinary-consortium project aimed at scientifically validating South African medicinal plants for the treatment of malaria. The in vitro antiplasmodial activity of extracts of these plants warranted further investigation to identify the biologically active components. Bio-assay guided fractionation based on in vitro antiplasmodial activity against the D10 P. falciparum strain was used to identify the compounds responsible for the observed activity. Compounds were purified using silica gel column chromatography. The structures of the isolated compounds were elucidated using spectroscopic techniques. Bioassay-guided fractionation of the organic extracts of V. staehelinoides leaves identified a pair of structurally-related hirsutinolides with significant in vitro antiplasmodial activity. The compounds were found to be cytotoxic at similar concentrations but proved to be interesting scaffolds for potential structure-activity relationship studies. Three germacranolides and two eudesmanolides were identified through bioassay-guided fractionation of the organic O. piluliferum extract. Selected derivatizations were conducted in order to fully characterize the compounds. The absolute configuration of the major active germacranolide was determined using Mosher's method. The effect of the reduction of the <font face="symbol"> a</font>-methylene group of the major active germacranolide on antiplasmodial activity and cytotoxicity was also investigated. The 5 compounds and the reduction product were found to possess varying degrees of in vitro antiplasmodial activity and cytotoxicity. None was sufficiently active or selective to be a viable drug candidate but the potential for further structure-activity relationship studies exists. / Dissertation (MSc (Chemistry))--University of Pretoria, 2007. / Chemistry / unrestricted

Diarrhea is a global concern that the United Nations Children’s Fund (UNICEF) and the World Health Organization (WHO), have confirmed to be the second major cause of death in children under the age of five. Major bacterial pathogens that cause diarrhea include Escherichia coli, Salmonella species, Shigella species and Staphylococcus aureus. Antibiotic therapy is recommended depending on the severity and presentation of the disease; however, the appearance of antibiotic-resistant bacteria is an emerging global threat to the ability to treat these bacterial infections. This situation could be overcome by the discovery of new natural antibiotics. Plants have been a source of medicine for centuries and have been used to treat diseases including diarrhea. This makes plants a natural potential target to study for their antibiotic properties. The objective of this study was to determine the antibiotic properties of medicinal plants against known pathogens that cause bacterial diarrhea. Three medicinal plants, Cassia abbreviata, Kigelia africana, and Geranium incanum were investigated for their antimicrobial properties against these strains of microorganisms: American Type Culture Collection (ATTC) and Clinical Strains (CS). The plant materials were ground into powder, which was then dissolved in methanol, acetone and distilled water to extract the active compounds. The plant extracts were then used to (i) determine their antibiotic activity, (ii) determine the minimum inhibitory concentration (MICs), (iii) analyze the thin layer chromatography (TLC) fingerprints, and (iv) analyze the autobiography assay. The results obtained in this study met the aim and objectives of this study. The antimicrobial activities of the selected plants were obtained as discussed in Chapter 2 and 3. These results indicated that the traditional plants could be used as antimicrobials. In the screening assays, the test microorganisms were inhibited by the plant extracts, when they were subjected to plant extracts. This was performed on Mueller Hinton agar as sensitivity testing, which revealed clear zones of inhibition. The MIC values for each plant extract were established which ranged from 0.101 to 13.3 mg/dl. The TLC analysis revealed the spots which contained the active compounds which inhibited the bacterial growth. A bioautography assay was performed on the TLC plates, which exposed the exact spots containing the active compound inhibiting the bacteria. These results are clearly consistent with what former scientists have observed. Detailed explanations on the results are in Chapter 3 and 4 of this paper. It is important to note that all the procedures performed in this study were in vitro assays. Some effective in vitro assay activity may not always result in the same effective in vivo activity, because some active compounds may be metabolized and degraded into inactive metabolites. For this reason, the in vitro results obtained in this study, may not reflect the true effectiveness of the compounds in in vivo trials. It is therefore advised that future scientists should take a step further in analyzing the plant extracts through in vivo assays. Further testing and study on these plants at an advanced molecular level will be beneficial in the medical fields in the search for new antibiotics to treat infectious diseases. Purification and further analysis of their products can be helpful in the production of pure natural medicines. This will discover the active ingredients and compounds responsible for inhibition of the microorganisms. This will make the compounds potential candidates for a scientific validation and analysis for future scientists to bring a new dawn in the fight against infectious diseases.

This study used cross-sectional survey data to estimate farmers` perceptions of, and commonly cultivated ILVs, factors that influence the participation of smallholder famers in the production of Indigenous Leafy Vegetables and its contribution to household food security]. With regard to farmers` perceptions of ILVs, descriptive results reveal that a majority of the people from the study area share positive perceptions with respect to ILVs. Regression estimates for determinants of participation indicate that the production of ILVs is primarily conditioned by shared perceptions and institutional factors rather than the socio-economic attributes of farmers. Public policies that address the institutional framework (extension, credit, market and social networks) in favour of ILVs are more likely to promote production. Also, more research on the documentation and benefits of ILVs, supported by investments targeting educational campaigns towards promoting positive attitudes and dispelling fears and myths surrounding ILVs, will further promote production. With reference to the contribution of ILVs to food security, descriptive results indicate that participation in the production of ILVs leads to a higher HDDS and a lower HFIAS. Regression estimates further revealed that participation positively contributes to a higher HDDS and a lower HFIAS, suggesting that households who participate in the production of ILVs are more likely to be food secure than non-participants. Therefore, participation in the production of ILVs has significant potential to address household food security.

Helicobacter pylori classified as a class 1 carcinogen is a common human pathogen implicated in certain gastrointestinal diseases. Helicobacter pylori infection is acquired mainly in childhood, especially in developing countries. H. pylori infection causes peptic ulcer, duodenitis, gastritis and cancer. The growing resistance of H. pylori to antibiotics used in its treatment as well as other innate limitations of the triple therapy has necessitated a search for alternative treatment from natural sources which could be readily available, less cost effective. The antimicrobial activity of solvents (acetone, ethanol, methanol, chloroform and water) crude extracts of Lippia javanica were investigated against 31 H. pylori strains by the agar well diffusion technique. The minimum inhibitory concentration (MIC) was determined by spectrophotometric analysis at 620 nm using the broth micro dilution method and the rate of kill by broth dilution method. Phytochemical analysis was also performed. H. pylori standard strain NCTC 11638 was included as a positive control. Metronidazole and amoxicillin were used as positive control antibiotics. The ANOVA test was used to analyze the results using SPSS version 17.0. The strains were inhibited by all the extracts with inhibition zones of diameter ranging from 0-36 mm and 0-35 mm for the control antibiotic, clarithromycin. The MIC90 ranged from 0.039- 0.625 mg/mL for acetone; 0.039-1.25mg/mL for methanol, 0.00195-0.313 mg/mL for ethanol; 0.01975-2.5 mg/mL for metronidazole and 0.0048-2.5 mg/mL for amoxicillin. Acetone extract completely inhibited strain PE369C at MIC (0.1 mg/mL) and 2× MIC (0.2 mg/mL) in 18h and at ½× MIC (0.05 mg/mL) in 36h. Strain PE466C was completely inhibited at 4× MIC in 72h. Phytochemical analysis revealed the presence of flavonoids, saponins, tannins, steroids and alkaloids. The results indicate that the extracts of the leaves of L. javanica may contain compounds with anti-H. pylori activity and merits further study to identify the compounds.

This thesis aimed to investigate the potential to increase young children s vegetable consumption by using caregivers as facilitators. This was achieved in two parts. Part I set out to investigate whether parent led interventions using three known successful methods of offering can be effective for increasing children s acceptance of a disliked vegetable. Three studies were conducted for Part I. The first tested the efficacy of these interventions, the second investigated the role of individual factors in intervention success, and the third examined the longitudinal efficacy of such interventions over two, six and 12 months. The findings suggested that parent led home-based interventions may be successful for increasing children s acceptance of disliked vegetables in the short-term, and that such interventions may be more successful for children who are more sociable and less fussy eaters. While these interventions may not be successful for sustained long-term changes, there was a lack of statistical power for these analyses and further studies with larger samples are required. Part II of the thesis sought to investigate the wider variety of methods which caregivers use to offer vegetables to their children, as well as the possible barriers to offering. These studies worked towards informing the design of future interventions as well as providing information for caregivers on achieving a healthful diet in their children. This was achieved via two studies which used qualitative and quantitative methods. One study used focus groups to gather a comprehensive report of caregivers methods of offering, as well as caregivers perceived influences on how and whether they offer their child vegetables. Methods of offering vegetables formed three main categories: active/behavioural methods, passive methods, and food manipulations. The influences on offering which caregivers perceived formed four categories: information, cost, caregiver factors, and child factors. These methods and influences were then assessed in a large scale cross-sectional study. This study examined which methods caregivers perceive as successful for encouraging consumption of vegetables, as well as assessing predictors of offering vegetables and children s vegetable consumption. Caregiver factors predicted reoffering of rejected vegetables while a combination of caregiver and child factors predicted children s consumption of vegetables. A number of discrepancies were found between methods caregivers perceived as successful and those which were associated with greater consumption of vegetables. As food fussiness was identified as a significant factor in children s consumption of vegetables, a final study investigated whether children categorised as fussy or not fussy with vegetables differed on a number of caregiver and child factors. Differences were found between these groups on both caregiver and child factors. Using a mixed methodology, the research in this thesis investigates possibilities for increasing vegetable consumption in early childhood and highlights the central role or caregivers in this process. Together, these findings suggest utility of whole family interventions aimed at increasing vegetable consumption, as well as providing caregivers with information on how best to offer vegetables to children of this age.

Please read the abstract in the section 00front of this document / Dissertation (MSc (Plant Physiology))--University of Pretoria, 2005. / Plant Science / unrestricted

During the cold reduction of steel sheet in a rolling mill, rolling oils are used for lubrication to provide the desired steel surface. Rolling oil formulations consist largely of mineral oils, glycerides and/or synthetic esters, fatty acids, emulsifiers and additives. These oils are generally used as 2-5% emulsions and will be subjected to high temperature and pressure during use. This results in chemical changes within the oil that can affect steel surface cleanliness after annealing. It is advantageous to have rolling oils that are stable but easily removed during annealing and leaving a minimal amount of residues. Thus in the field of rolling mill technology the surface quality of rolled product and stability of rolling oils are critical in the selection of lubricants. Additionally, production cost and environmental impact are also critical in the selection of lubricants. In this study, the performance of vegetable-based rolling oils was investigated by recording the FTIR spectra of the oils using Horizontal Attenuated Total Reflectance, an internal reflection accessory, before and after systematic heat treatment. Evidence was found that the vegetable-based oils degraded on heating and the spectroscopic analysis indicated that this was due to rearrangement of unsaturated components from a cis to a trans configuration. / Dissertation (MSc)--University of Pretoria, 2008. / Chemistry / unrestricted