Mbatha, Treasure Fundisiwe2016-02-262016-02-262016-02-26http://hdl.handle.net/10539/19756Dissertation submitted to the Faculty of Health Sciences, University of the Witwatersrand, Johannesburg, in fulfillment of the requirements for the Degree of Master of Science in Medicine. Johannesburg 2015Oral candidiasis which is commonly observed in immune compromised individuals, is caused by Candida albicans. Pathogenicity of C. albicans is dependent on virulence factors such as adherence to surfaces including host tissues, formation of hyphae and the production of hydrolytic enzymes. C. albicans isolated from HIV positive patients are known to express greater virulence and are considered to be more virulent than isolates from HIV negative patients. Antifungal drugs are available, but in recent years C. albicans has developed resistance to some of these drugs which has necessitated search for newer antifungal compounds. Medicinal plants can be an excellent resource for the discovery of new therapeutic drugs. Punica granatum (pomegranate) which is grown worldwide is known to have antimicrobial properties. Some studies have shown that at high concentrations P. granatum has antifungal properties. However, high concentrations are difficult to maintain in body cavities with secretions. Therefore, this study investigated the antifungal properties of the peel and seeds of P. granatum and the effect of peel extract on the virulence properties of C. albicans isolated from HIV positive and HIV negative patients. P. granatum was collected, fruit peel and seeds were separated, dried and pulverised. Extracts were prepared using various solvents and yields were calculated. Antifungal properties was determined against 10 strains of C. albicans isolated from the oral cavities of each of the HIV positive and HIV negative patients using a microdilution technique. Minimum inhibitory concentrations and minimum fungicidal concentrations were recorded. Subinhibitory concentration (3.125 mg/ml) of methanol extract of P. granatum was selected and its effect on the adherence ability, germ tube formation and the production of phospholipase, proteinase and lipase by C. albicans was investigated using well described laboratory techniques. For the fruit peel, methanol (0.67g/1g of dry powder) proved to be the best solvent for the crude extraction. For the seeds, hexane, dichloromethane/methanol and ethyl acetate produced the best yield (0.2 g/1g of powder). For the peel, minimal inhibitory concentration and minimal fungicidal concentration values of the ethanol, acetone, hexane, ethyl acetate and water against all the test isolates was 1.56 mg/ml. The lowest minimal inhibitory concentration and minimal fungicidal concentration of 0.39 mg/ml was obtained with ethyl acetate solvent. For the seeds, the median minimal inhibitory concentration and minimal fungicidal concentration values of the ethanol, acetone, hexane and water against all the test isolates was 1.56 mg/ml. All the test isolates showed an adherence property to the oral epithelial cells. In the C. albicans isolated from HIV positive and HIV negative patients adherence was reduced by the plant extract from 331 to 321 cells (p=>0.05) and from 242.9 to 213.3 cells (p=>0.05) respectively. Germ tube formation by the C. albicans isolated from HIV positive patients and HIV negative patients was significantly reduced by the plant extract, from 68.7 to 51.1 cells (26% reduction – p<0.01) and 72.4 to 38.4 cells (34% reduction – p<0.01) respectively. In the presence of plant extract, the production of phospholipase by the C. albicans isolated from HIV positive patients and HIV negative patients either increased or decreased by 1 to 4% which was not significant. The plant extract reduced the production of proteinase by the C. albicans isolated from HIV positive patients and HIV negative patients by 2 to 3% which was also not significant. Similarly, production of lipase by the isolates from both the groups was reduced by 6 to 9% (p=>0.05). The reduction in the adherence ability, germ tube formation and the production of hydrolytic enzymes was not significantly different between the isolates from HIV positive and HIV negative patients. High concentrations of crude extract of P. granatum peel have an antifungal effect and subtherapeutic concentrations can inhibit the germ tube formation which is necessary in the pathogenesis of oral candidiasis. Therefore, pomegranate peel has a potential to be developed into a therapeutic agent, although further research is required.enThesis