Bacterial resistance to antibiotics has been a great problem for many years. The degree of resistance and the speed with which resistance develops varies with different organisms and different drugs. Enzymes called β-lactamases are produced by bacteria and are one mechanism in which bacteria develop antimicrobial resistance. Gram-negative bacteria producing enzymes called ESBLs because of their wide substrate range are of a particular concern in nosocomial infections. In many countries people still use traditional medicine derived from plants as an alternative to the Western medicine due to increased cost of Western medicine and microbial resistance of antibiotic treatments. Biologically active compounds isolated from plants species are used in herbal medicine. Because of the high prevalence of the ESBLs and their increasing resistance to the antibiotics, this research study was done to test the antimicrobial activities of selected medicinal plants of the Eastern Cape; G. incanum, D. angustifolia and E. autumnalis which were traditionally used to treat various infections. The in vitro antimicrobial activity of three different extracts (acetone, methanol & distilled water) and the traditional preparations of the three plants were tested against the selected strains of ESBL-producing bacteria, non β-lactamase producers and the different fungal species. The extracts were screened against 26 Gram-positive bacterial strains, 53 Gram-negative bacterial strains and 15 fungal strains. The Gram-positive bacteria included strains from S. aureus, B. cereus and E. faecalis. The Gram-negative bacteria included strains from E. ii coli, E. cloacae, K. pneumoniae, P. aeruginosa and Acinetobacter spp. The fungal strains included 9 strains of Candida albicans and a single strain of each of the following opportunistic fungi, Mucor sp, Geotrichium sp, Penicillium sp, Fusarium sp and Rhizopus sp. The agar dilution assay was used for the antimicrobial screening of the plants extracts and for the determination of the MICs. The Ames test was performed for the determination of probable carcinogenicity of the extracts of G. incanum and D. angustifolia. The distilled water extracts followed by acetone extracts of the plants revealed the highest antimicrobial activity against the different microbial strains. The extracts of G. incanum followed by the extracts of D. angustifolia inhibited the highest number of microbial strains. The extracts of E. autumnalis did not show any antimicrobial activity against all the pathogens in this study. More of the Gram-positive bacteria were inhibited by the plant extracts. The lowest MIC was obtained with Gram-positive bacteria. The bacterial strains of E. faecalis and P. aeruginosa were not inhibited by any of the plants extracts in the agar dilution assay yet Acinetobacter species which are MDR were inhibited by the distilled water and methanol extracts of G. incanum. A single strain of Mucor sp was the only spore forming fungi that was inhibited by the distilled water extracts of G. incanum. None of the plants extracts showed any mutagenic effects on the TA100 S. typhimurium strains incorporated on the Ames test. Apart from revealing of new antimicrobial agents that may be used against resistant organisms, the proper use of antimicrobial agents should be recommended. The study has highlighted a need for further investigations on the properties of the medicinal plants used in this study.

Tulbaghia (Alliaceae) is a genus of plants with medicinal, ornamental and nutritive value. Different plant parts such as roots, bulbs, leaves and flowers are used in the treatment of a variety of conditions. The bulbs of Tulbaghia violacea are used as a remedy for pulmonary tuberculosis as well as an anthelmintic. Due to the extensive harvesting of plants in this genus, the genus is susceptible to overexploitation and may eventually become threatened with extinction. It was therefore the aim of this study to systematically examine the micropropagation of Tulbaghia ludwigiana and Tulbaghia violacea, as well as to evaluate the antimicrobial and phytochemical properties of micropropagated plants. Seeds of T. ludwigiana and T. violacea were successfully decontaminated using 70% ethanol, 1% Benlate and 3.5% NaOCl. Temperature played a significant role in the germination of both species while light did not play a significant role in this process. Light did not play a significant role in the stomatal density of T. violacea seedlings. Hypocotyls were the regenerative part of the seedlings in both species. A low number of shoots was yielded by the combination of various concentrations of NAA and mTR in the growth medium in both species. There were more isoprenoid cytokinins than there were aromatic cytokinins in each of the seedling sections of T. violacea that were analysed, with tZ being the predominant isoprenoid cytokinin, while BA was the predominant aromatic cytokinin. Shoots of both species were successfully rooted in a medium with IBA, while some shoots had simultaneously rooted during shoot multiplication. Potting soil and vermiculite were used in the acclimatization of both species, where T. violacea plantlets acclimatized successfully. This was not the case for T. ludwigiana. Micropropagated T. violacea plantlets contained higher concentrations of phytochemical compounds and displayed better antibacterial activity than outdoor-grown plants. / Thesis (M.Sc.)-University of KwaZulu-Natal, Pietermaritzburg, 2011.

The use of traditional medicine is a popular practice in South Africa especially among rural dwellers due to several reasons such as availability of natural products, cultural beliefs, preference of natural products to synthetically derived drugs and the high cost of modern drugs. Traditional healers in South Africa play key roles in administering treatment for all sorts of ailments using plants. The aim of this study was to evaluate the efficacy of seven selected medicinal plants that are used in traditional medicine to treat stomach-related ailments for their pharmacological and phytochemical properties. Plant material was extracted sequentially with ethyl acetate (EtOAc), ethanol (EtOH) and water. The extracts were evaluated for their antimicrobial activities using the microdilution technique against two Gram-positive (Enterococcus faecalis ATCC 19433 and Staphylococcus aureus ATCC 12600) bacteria and a Gram-negative (Escherichia coli ATCC 11775) bacterium. A modified microdilution technique was used to screen for antifungal activity against a yeast-like fungus (Candida albicans ATCC 10231). Only the EtOAc extract of Tetradenia riparia demonstrated good antibacterial activity against the Gram-negative E. coli, all the other extracts that were active only showed good antibacterial activity against the two Gram-positive (E. faecalis and S. aureus) bacteria with MIC values <1 mg/ml. None of the extracts that exhibited good inhibitory activity showed corresponding bactericidal activity against the bacterial test strains, suggesting that the observed activity were all inhibitory. Good antifungal activity with an MIC value <1 mg/ml was observed in only 5 extracts, and none of the extracts exhibited corresponding fungicidal activity. The in vitro colorimetric assay for anthelmintic activity against Caenorhabditis elegans revealed that almost all the extracts possessed moderate to high anthelmintic properties. The EtOAc extract of T. riparia had the best activity at MLC value of 0.004 mg/ml. The anti-inflammatory activity of the plant extracts was tested using the cyclooxygenase assays to determine their inhibitory potential against COX-1 and COX-2 enzymes. All the EtOAc extracts demonstrated both COX-1 and COX-2 inhibitory activity in the range of 50.7 ± 2.4 to 99.5 ± 0.5%. Apart from the EtOH extracts of C. multicava that showed high inhibitory activity against both COX-1 and COX-2, all the other EtOH extracts were COX-2 selective. Aqueous extracts exhibited poor inhibitory activity against both COX-1 and COX-2 enzymes with the exception of T. riparia and Coddia rudis that showed good inhibitory activity (69.1 ± 0.9 and 92.65 ± 0.7%) against COX-1 and COX-2 respectively. The standard plate incorporation assay for the Ames test was carried out to determine the potential genotoxic effects of the plant extracts and this revealed that all the extracts were non-mutagenic towards Salmonella typhimurium tester strains TA98, TA100 and TA1537 without metabolic activation. However, further studies incorporating metabolizing enzymes are needed to confirm the safe use of the studied plants. Phytochemical analysis revealed relatively high amounts of total phenolics, gallotannins and flavonoids in all the evaluated plants. Total and steroidal saponins were detected in only two plant samples, Canthium spinosum and Cassinopsis ilicifolia (bark). These findings present useful information on the types of bioactive compounds that could be responsible for the pharmacological activities observed among some of the plant extracts. The results obtained in this study showed different levels of pharmacological activities among all the evaluated medicinal plants which provide scientific validation for their use in traditional medicine as antimicrobial agents. Phytochemical analysis provides valuable information for further study that will be aimed at isolation and identification of the bioactive principles in the evaluated plant species. / Thesis (M.Sc.)-University of KwaZulu-Natal, Pietermaritzburg, 2011.

Two experiments were conducted to determine the optimal brining levels and effective chlorinated antimicrobials in three selected commercial poultry abattoirs of south Africa.The objective of the study was two fold: Firstly, the primary objective of the study was to determine the optimal inclusion level of brine for application in chicken processing to elongate the shelf life by reducing spoilage bacteria under refrigeration stage while the secondary objective of the study was to determine the most effective chlorinated antimicrobial to be applied in poultry processing plants to reduce spoilage bacteria. For each experiment, a complete randomized design was used. The general linear model procedure was used to determine the effects of brining and chlorine antimicrobials on the Psychrotrophic bacterial load of individually quick frozen (IQF) chicken portions. Simultaneously, a quadratic type equation was used to determine the optimal inclusion level of brine in relation to the responses of Psychrotrophic bacterial loads. The results indicated that control samples (0% brine) had higher (P < 0.05) bacterial load than all samples injected with various injection levels. There were significant differences (P < 0.05) between samples injected with 15% and 20% for all major abattoirs combined. However, there were no differences (P > 0.05) between samples injected with 20% and 25% brine, respectively. In addition, there was a significant difference (P < 0.05) in Psychrotrophic bacterial load between the samples treated with 25% and 30% brine inclusion level as well as those treated with 30% and 35% brining levels in all abattoirs. Futhermore, the results of the study also showed that Acidified Sodium Chloride had significantly lower bacterial load than both aqueous chlorine and chlorine dioxide. However, the effect of percentage brining on average Psychotrophic bacterial count had minimum quadratic values of 24.45 – 0.517 brining + 0.805 brining2 with r = 0.995; r2= 0.989, with optimum percentage brining dose being 43.08%. By extension, the result implies that the lowest reduction in spoilage bacteria is attained at 43.08% of brine inclusion level. These findings have implications on the most effective and convenient antimicrobial to be used in chicken abatoirs as well as reduction of psychotrophic bacterial load on individually quick frozen (IQF) chicken portions / Agriculture, Animal Health and Human Ecology / M. Sc. (Agriculture)