An investigation into the antimicrobial and anticancer activities of Geranium incanum, Artemisia afra and Artemisia absinthium
- Authors: Freidberg, Ryno
- Date: 2009
- Subjects: Medicinal plants -- South Africa , Cancer -- Alternative treatment -- South Africa , Anti-infective agents
- Language: English
- Type: Thesis , Masters , MTech
- Identifier: vital:10122 , http://hdl.handle.net/10948/1045 , Medicinal plants -- South Africa , Cancer -- Alternative treatment -- South Africa , Anti-infective agents
- Description: It has been estimated that between 3000 and 4000 plant species are used for their medicinal properties throughout South Africa, with approximately 27 million South Africans making use of traditional medicines. Of this 27 million, 3 million South Africans rely on traditional medicine as their primary source of health care. Of the 250 000 to 500 000 known plant species, very few have been investigated for their pharmacological qualities, and compounds of significant medicinal value may still remain undiscovered in many plant species. The aims of this study included investigating the antimicrobial properties of Geranium incanum and Artemisia afra, both plants traditionally used for their medicinal properties, and comparing the antimicrobial activity of the latter to that of Artemisia absinthium, as well as investigating the anticancer properties of G. incanum and A. afra, and comparing the anticancer activity of the latter to that of A. absinthium. Infusions, aqueous-, methanol- and acetone extracts of the three plants were prepared and used for anticancer and antimicrobial screening. Plant specimens used to prepare extracts for antimicrobial activity were collected and extracted over three seasons, while extracts used for anticancer screening were prepared from plants collected during the summer only. Considerable variation existed in the percentage crude extract yields obtained when different extractants were used, while the season in which the plants were harvested and extracted also appeared to play a significant role in the amount of extract obtained. The plant extracts were screened for antimicrobial activity against various strains of Candida albicans, Escherichia coli, Pseudomonas aeruginosa, Enterococcus faecalis, Staphylococcus aureus and Bacillus cereus, using an agar dilution method. G. incanum and A. afra possessed activity for C. albicans, while all three plants showed activity for S. aureus and B. cereus. Activity was largely dependent on the extraction method used. iii The 3-[4,5-dimethylthiazol-2-yl]-2,5-diphenyl tetrazolium bromide (MTT) assay was used to screen for anticancer activity of the respective extracts, at varying concentrations, against MCF-7 (human breast adenocarcinoma) cells, HT-29 (human colonic adenocarcinoma) cells and HeLa (human cervical cancer) cells. All of the extracts showed cytotoxic activity in all three cell lines to varying extents, depending on the extract used and cell line screened. The acetone extract of A. afra proved to be the most effective inhibitor with the lowest IC50 (2.65 ± 1.05 μg/ml) having been shown in MCF-7 cells. A. afra and A. absinthium showed similar inhibitory patterns, with the methanol- and acetone extracts having been the most potent inhibitors of each of the respective cell lines in general. Fluorescence microscopy employing 4',6-diamidino-2-phenylindole dihydrochloride (DAPI) and propidium iodide (PI) staining indicated that the acetone extract of A. afra induces apoptosis in MCF-7 cells as apposed to necrosis, and the results were comparable to those obtained for cells exposed to cisplatin. Screening of the A. afra acetone extract for toxicity in normal human cells using the CellTiter-Blue® assay indicated the extract to be toxic to peripheral blood mononuclear cells (PBMC’s) at concentrations comparable to that for MCF-7 cells, while cell cycle analysis of MCF-7 cells exposed to the A. afra acetone extract indicated the extract’s ability to induce apoptosis comparable to that of cisplatin, with the extract exerting its activity at a point during or just prior to the S phase of the cell cycle.
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- Date Issued: 2009
Production of biologically active recombinant HIV-1 protease and intehrase for the purpose of screening medicianl plant extracts
- Authors: Bosch, Janine
- Date: 2009
- Subjects: Medicinal plants -- South Africa , HIV infections -- Alternative treatment -- South Africa , Materia medica, Vegetable -- South Africa
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:10325 , http://hdl.handle.net/10948/1056 , Medicinal plants -- South Africa , HIV infections -- Alternative treatment -- South Africa , Materia medica, Vegetable -- South Africa
- Description: Human immunodeficiency virus (HIV) and its gradual weakening of the immune system is an ever growing threat. Acquired immune deficiency syndrome (AIDS), the final stage of HIV, renders a person vulnerable to various opportunistic infections, which in the end lead to death. Apart from intensive vaccine studies, treatment research mainly focuses on preventing the individual HIV enzymes (reverse transcriptase, integrase and protease) from performing their functions. Entry inhibitors, however, block viral entry into the cell, while antisense drugs lock onto the viral genome to keep it from functioning. In this study production of active recombinant HIV-1 protease and integrase was attempted for future drug screening programs. HIV-1 protease was cloned into a pET28b(+) vector and expressed in ROSETTA(DE3)pLysS cells. The protein was purified using a nickel-affinity column utilizing the hexa-histidine tag encoded by the vector. Gel filtration chromatography was attempted after refolding of the protease, but protease yield seemed to decrease with the additional purification step. Partially purified protease was characterized with kinetic studies. Kinetic parameters of HIV-1 protease were determined to be Km = 592 μM, Vmax = 0.59 μM/min and kcat = 31 s-1. HIV-1 integrase, which was cloned into a pET15b vector, was expressed in E. coli BL21(DE3) cells. The coding sequence had been mutated to introduce the amino acid substitutions F185K and C280S, increasing solubility of the protein. The first step in purification of this protein was nickel-affinity chromatography, after which cation exchange chromatography was attempted. HIV-1 integrase concentration was low throughout experiments and no clear elution from the cation exchange column could be observed. A non-radioactive enzyme linked HIV-1 integrase assay failed to detect integrase activity. Modifications to future studies of the integrase are suggested in the chapter involved.
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- Date Issued: 2009
Social learning processes of HIV/AIDS women caregivers on their use of traditional foods and medicinal plants : the case of Raphael Centre and Keiskamma Art and Health Centre communities of practice, Eastern Cape Province, South Africa
- Authors: Shonhai, Venencia F
- Date: 2009
- Subjects: Keiskamma Art Project (South Africa) , Women caregivers -- South Africa -- Eastern Cape , HIV infections -- Study and teaching -- South Africa , AIDS (Disease) -- Study and teaching -- South Africa , HIV-positive persons -- Care -- South Africa -- Eastern Cape , Medicinal plants -- South Africa , Natural foods -- South Africa
- Language: English
- Type: Thesis , Masters , MEd
- Identifier: vital:1768 , http://hdl.handle.net/10962/d1003653
- Description: The scale of people being infected by HIV/AIDS (Human Immunodeficiency Virus /Acquired Immune Deficiency Syndrome) has meant that the family and the community have had to become involved in caring for the sick (Van Dyk, 2005). This has inevitably led to the emergence of informal caregivers in the form of family members caring for their relatives (Kipp, Nkosi, Laing & Jhangri, 2006). The research investigated the social learning of women caregivers looking after people living with HIV/AIDS, with emphasis on caregiving practices related to how they use traditional foods and medicinal plants. The research was undertaken in Grahamstown at the Raphael Centre and in Hamburg at Keiskkamma Health Centre and Art Project, Eastern Cape, South Africa. Data was collected using interviews, focus group discussions and diaries written by participants. The data was analyzed in two phases: the first phase involved reading the interview transcripts and collating the responses into analytical memos that were captured into broad categories, while the second phase made use of the community of practice analytical framework to further analyze the data to get better understanding of the social learning processes. This study reveals that participating in a community of practice like Raphael Centre and Keiskamma Health Centre enables caregivers to learn about caregiving. It also reveals that within these communities of practice there are varied learning processes that take place, such as observational and collaborative learning. The research also revealed that caregivers learn from the communities from which they come, for example caregivers learn about traditional food and medicinal plants which they use from their family members, friends, other caregivers as well as non governmental organizations. The research found that caregivers are influenced in their learning and practices by a number of factors which include their own experiences, ambivalent messages from different stakeholders concerned with fighting HIV/AIDS and exposure to new information. The research recommends that diverse learning processes in a community of practice and outside a community of practice should be encouraged and strengthened. It also recommends that HIV/AIDS caregiving options should be strengthened by drawing on experience and knowledge of caregivers. Caregivers should be encouraged to be selfsustaining to improve their caregiving practices. Stakeholders in the field of HIV/AIDS should be alert to and address ambivalence on use of medicinal plants. Existing programmes that enable women to learn about new information on HIV/AIDS should be strengthened.
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- Date Issued: 2009