Thesis (M.Sc. (Microbiology)) -- University of Limpopo, 2019 / Schkuhria pinnata was selected for this study based on its use in traditional medicine. This study was aimed at isolating and charactserising antimycobacterial compounds from S. pinnata. Different extraction procedures coupled with solvents of varying polarities were used in extraction of the plant materials. Solvents of intermediate polarity had the highest mass of the extracts and serial exhaustive extraction was the best extraction procedure which extracted high amounts of plant material obtained with dichloromethane solvent. The chromatograms were developed in three solvent systems (BEA, CEF and EMW) and sprayed with vanillin-sulphuric acid reagent for colour development. Different colours on the chromatograms indicated various phytochemical constituents. Standard chemical tests confirmed the presence of tannins, flavonoids, alkaloids, phlabotannins, terpenes, steroids, cardiac glycosides and saponins. It was discovered that S. pinnata possesses high phenolic and tannin content which could be behind the antioxidant and anti-inflammatory activities observed. Antioxidant activity was analysed using 2, 2–diphenyl-1-picrylhydrazyl (DPPH) qualitative and quantitative experiments. Chromatograms were sprayed with 0.2% DPPH solution, yellow bands or spot against the purple background indicated the presence of antioxidant compounds. On quantitative analysis methanol extracts had a good scavenging activity at various concentrations. Ferric ion reducing power of antioxidants from plant extracts was determined using FRAP assay. S. pinnata extracts had high ferric reducing power which was in a concentration-dependent manner. Antimycobacterial activity was evaluated using Bioautography and broth microdilution assays. Plant extracts indicated antimycobacterial activity observed on bioautograms with low MIC values ranging from 0.27 mg/ml to 2.5 mg/ml. African green monkey Vero kidney cells were used to evaluate the toxicity of crude extracts. The plant extract had cytotoxic value of 25 µg/ml with a selectivity index of 0.02 SI. It was observed that S. pinnata had anti-inflammatory activity on LPS-induced Raw 246.7 macrophage cells in a concentration-dependent manner. Bioassay guided fractionation on column chromatography managed to isolate two compounds which were characterised using nuclear magnetic resonance techniques. The compounds were elucidated to be helaingolide and eucannabinolide sesquiterpene lactones. Biological assays indicated that the compounds were active against Mycobacterium smegmatis. The compounds were toxic to Vero monkey kidney cells with less than 30 µg/ml LC50 value and <1 selectivity index. These compounds had a good anti- inflammatory activity on LPS-induced Raw 246.7 macrophage cells which was in a concentration dependent manner. The compounds can be used as new leads in the development of anti-inflammatory and antimycobacterial drugs. The crude extracts and the isolated compounds from S. pinnata should be evaluated for their cytotoxicity and anti-inflammatory effects in in vivo experiments. / National Research Foundation (NRF)

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A dissertation submitted in fulfilment of the requirements for the degree of Masters in Science in the School of Molecular and Cell Biology, University of the Witwatersrand Johannesburg, 2013 / Cervical cancer is a gynaecological malignant disorder and is a common cause of death in women of the sub-Saharan Africa, striking nearly half a million of females each year worldwide. Cervical cancer is due to the persistence infection of human papillomavirus (HPV), a formidable virus that targets the cervix and is present in most cancers of the cervix. In South Africa, plants used to treat cancer are rare and there is a need for screening further plant extracts in order to identify potentially new anti-cancer drug discovery leads. The purpose of this study was to screen Tulbaghia violacea (TV) and Agave palmeri (AG) for anti-cancer therapy in the cervical cancer cell lines HeLa and ME-180 and in the fibroblast cell line KMST-6. Staurosporine (ST) was used as a positive control. AG and TV crude plant extracts were screened for apoptosis induction, followed by elucidation of the role of Bax, Bcl-2, p53, Rb, RBBP and Mdm2 genes in cervical cancer. Plant extracts of TV and AG were time (24 hours) and dose (50, 100, 150 μg/ml) dependently screened against cervical cancer cell lines HeLa, ME-180 and in KMST-6 for anti-cancer activity using the thiazolyl blue test (MTT) assay. With an IC50 ~ 150 μg/ml, T. violacea extract exhibited significant cytotoxicity on both HeLa and ME-180 cancer cell lines, whilst A. palmeri was cytotoxic to ME-180 cells and 25nM ST as a positive control had a cytoxicity effect on all cell lines including the KMST-6, yet TV and AG had no cytotoxic effect on KMST-6. The annexin-V/FITC detection assay was performed to evaluate the occurrence of apoptosis. Crude extracts of TV and AG together with ST induced significant apoptosis of HeLa, ME-180 and KMST-6 cells. The crude extracts were further analysed for DNA fragmentation, protein expression and gene expression by Western Blot and RT-PCR respectively, to investigate whether these extracts have an effect on the on the expression of Bax, Bcl-2, p53, Rb, RBBP6, Mdm2 and the relationship between p53 and RBBP6. Morphological and biochemical changes were seen in this study. A further mixed response by several genes was observed following treatment with the two plant extracts, where RBBP6 was seen to be spliced in cancer cells while Bax was induced and Bcl-2 was inhibited, but the levels of p53 remained the same. Preliminary, the extracts of TV and AG induce cell death by down-regulating Bcl-2 and Mdm2. Quantitative RT-PCR showed that when p53 was silenced RBBP6 was up-regulated and vice versa. From these results it was deduced that RBBP6 gene interacts with p53 during cervical cancer development. The anti-proliferative activity together with the characterization of p53, RBBP6 and Mdm2 and concentrations of these plant extract could be manipulated as diagnostic markers and potential therapeutic targets for cancer treatment; however, further studies on these plant extracts need to be performed to validate results obtained in this study.

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Thesis (MS)--University of Montana, 2009. / Contents viewed January 14, 2010. Title from author supplied metadata. Includes bibliographical references.

Thesis (M.A.)-University of KwaZulu-Natal, Durban, 2005. / Full text also available online. Scroll down to electronic link.

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Thesis (M.S.)--University of Texas at El Paso, 2008. / Title from title screen. Vita. CD-ROM. Includes bibliographical references. Also available online.

Thesis--University of Georgia. / eContent provider-neutral record in process. Description based on print version record. Includes bibliographical references (leaves 195-209).

Thesis (Ph. D.)--University of Wisconsin--Madison, 1984. / Typescript. Vita. eContent provider-neutral record in process. Description based on print version record. Includes bibliographical references (leaves 146-153).