Motivation: Diet and nutrition are important factors in the promotion and maintenance of good health throughout the entire life course. Their role as determinants of chronic noncommunicable diseases is well established. Alterations in diet, both positive and negative have strong effects on health throughout life. Consumers' awareness of a diet-disease relationship may stimulate interest in learning more about nutrition thus acquiring necessary knowledge for dietary improvement and disease prevention. Objectives: • To investigate South African metropolitan consumers beliefs and attitudes about the link between food and health. • To explore the demographic characteristics and beliefs of South African consumers regarding the link between food and health; and to investigate whether differences exist in this belief between gender, race, age group and Living Standard Measures (LSM). Methodology: One thousand nine hundred and ninety seven South African adults (≥16 years), representing the four major race groups of South Africa, were selected by stratified random sampling from metropolitan areas in South Africa. The sample was weighted based on the South African 2000 National census data, to be representative of the adult metropolitan population based on gender, age and race distribution. Trained field workers administered the questionnaire by conducting face-to-face interviews with South African consumers. The questionnaire was designed by a multidisciplinary team and contained a number of statements on eating habits, food and health. Results: There were no practically significant differences in consumers' responses in terms of gender or age. Practically significant differences were found between different race and LSM groups for some variables. A small practically significant difference was observed among the races in statement 1, and between LSM 2 to 3 and LSM 7 to 10; and between LSM 4 to 6 and LSM 7 to 10 in statement 1 and statement 6. In statement 2, a small practically significant difference was observed between Whites and Coloureds. Statement 4 indicated a small practically significant difference between Blacks and Indians. A medium practically significant difference was found between LSM 2 to 3 and LSM 7 to 10 for statement 4. A small practically significant difference was evident between Whites and Blacks; and between Blacks and Coloureds in statement 6. A medium practically significant difference was found between Blacks and lndians in statement 6. The overall response of South African consumers towards the belief that food has an effect on health, that food can influence health and the development of some diseases, and that healthy food is only for people that have a disease, was very positive. However 56% of South African consumers do not want to have to think about disease when choosing food. Conclusion: Results from this study reveal that South African consumers have some understanding of the dietdisease relationship and believe that there is some link between food and health. This belief however differs between age, gender, race and LSM group. However, more research with regards what influences people's eating behaviour, attitudes towards healthy food and beliefs about the dietdisease relationship needs to be done in South Africa. / Thesis (M.Sc.)--North-West University, Potchefstroom Campus, 2005

Motivation: Diet and nutrition are important factors in the promotion and maintenance of good health throughout the entire life course. Their role as determinants of chronic noncommunicable diseases is well established. Alterations in diet, both positive and negative have strong effects on health throughout life. Consumers' awareness of a diet-disease relationship may stimulate interest in learning more about nutrition thus acquiring necessary knowledge for dietary improvement and disease prevention. Objectives: • To investigate South African metropolitan consumers beliefs and attitudes about the link between food and health. • To explore the demographic characteristics and beliefs of South African consumers regarding the link between food and health; and to investigate whether differences exist in this belief between gender, race, age group and Living Standard Measures (LSM). Methodology: One thousand nine hundred and ninety seven South African adults (≥16 years), representing the four major race groups of South Africa, were selected by stratified random sampling from metropolitan areas in South Africa. The sample was weighted based on the South African 2000 National census data, to be representative of the adult metropolitan population based on gender, age and race distribution. Trained field workers administered the questionnaire by conducting face-to-face interviews with South African consumers. The questionnaire was designed by a multidisciplinary team and contained a number of statements on eating habits, food and health. Results: There were no practically significant differences in consumers' responses in terms of gender or age. Practically significant differences were found between different race and LSM groups for some variables. A small practically significant difference was observed among the races in statement 1, and between LSM 2 to 3 and LSM 7 to 10; and between LSM 4 to 6 and LSM 7 to 10 in statement 1 and statement 6. In statement 2, a small practically significant difference was observed between Whites and Coloureds. Statement 4 indicated a small practically significant difference between Blacks and Indians. A medium practically significant difference was found between LSM 2 to 3 and LSM 7 to 10 for statement 4. A small practically significant difference was evident between Whites and Blacks; and between Blacks and Coloureds in statement 6. A medium practically significant difference was found between Blacks and lndians in statement 6. The overall response of South African consumers towards the belief that food has an effect on health, that food can influence health and the development of some diseases, and that healthy food is only for people that have a disease, was very positive. However 56% of South African consumers do not want to have to think about disease when choosing food. Conclusion: Results from this study reveal that South African consumers have some understanding of the dietdisease relationship and believe that there is some link between food and health. This belief however differs between age, gender, race and LSM group. However, more research with regards what influences people's eating behaviour, attitudes towards healthy food and beliefs about the dietdisease relationship needs to be done in South Africa. / Thesis (M.Sc.)--North-West University, Potchefstroom Campus, 2005

Parkinson’s disease is the second most common age-related neurodegenerative disease after Alzheimer’s disease. The characteristic pathological feature of Parkinson’s disease is the loss of neurons in the substantia nigra pars compacta (SNpc), which leads to a striatal dopamine deficiency responsible for the major symptoms of Parkinson’s disease. These symptoms include tremor at rest, postural instability, bradykinesia and in the later stages of Parkinson’s disease, even psychosis. Presently, there is still no cure for Parkinson’s disease and all treatments are only symptomatic. Current research is therefore directed towards the prevention of further dopaminergic neurodegeneration, while the ultimate aim is the reversal of neurodegeneration. Monoamine oxidase (MAO) enzymes are responsible for the regulation and metabolism of monoamine neurotransmitters, such as dopamine. There are two MAO isoforms, MAO-A and MAO-B. Since MAO-B has greater activity in the basal ganglia, it is of particular importance in movement disorders, which include Parkinson’s disease. The selective inhibition of MAO-B, increases dopamine available for binding, and thus reduces Parkinson’s disease symptoms. MAO inhibitors also have neuroprotective potential and thus may slow down, halt and even reverse neurodegeneration in Parkinson’s disease. It is still unclear exactly how MAO inhibitors protect neurons, but one theory suggests that MAO inhibition decreases oxidative stress by reducing the formation of hydrogen peroxide, a metabolic by-product of MAO oxidation of monoamines. Normally, hydrogen peroxide is inactivated by glutathione (GSH), however, in Parkinson’s disease, GSH levels are low, resulting in the accumulation of hydrogen peroxide, which then becomes available for the Fenton reaction. In the Fenton reaction, Fe2+ reacts with hydrogen peroxide and generates an active free radical, the hydroxyl radical. This radical depletes cellular anti-oxidants, damage lipids, proteins and DNA. MAO inhibitors reduce the formation of hydrogen peroxide thus decreasing the formation of hydroxyl radicals and oxidative stress. The MAO inhibitory potential of natural and synthetic chalcones have been illustrated. For example, in 1987, Tanaka and co-workers determined that natural chalcones, such as isoliquiritigenin, have MAO inhibitory activity in rat mitochondria. In 2009, Chimenti and co-workers synthesized a series of 1,3-diphenyl-2-propen-1-ones which exhibited human MAO-B (hMAO-B) selective inhibitory activity. On the other hand, Robinson and co-workers (2013), synthesized novel furanochalcones which also had hMAO-B selective inhibitory activity. A reversible, competitive mode of binding was demonstrated by these compounds. Since the effect of heterocyclic substitution, other than furan on the MAO inhibitory properties of the chalcone scaffold remains unexplored, the aim of this study was to synthesize and evaluate further heterocyclic chalcone analogues as inhibitors of hMAO. RESULTS Design and synthesis: Heterocyclic chalcone analogues that incorporated pyrrole, 5- methylthiophene, 5-chlorothiophene and 2-methoxypyridine substitution were synthesized using the Claisen-Schmidt condensation reaction. All compounds were characterized with 1H-NMR, 13CNMR, IR, MS, and melting points were recorded. Purity was determined with HPLC analysis. MAO inhibition studies: The 50% inhibitory concentration (IC50) values and selectivity index (SI) of all compounds were determined using a fluorometric assay and kynuramine as substrate. Eight out of the ten synthesized compounds exhibited IC50 values < 1 μM, and can thus be considered as potent MAO-B inhibitors, while all compounds showed selectivity for the MAO-B isoform. Compound 10i was the most potent MAO-B inhibitor with an IC50 value of 0.067 μM and the highest SI of 240.7. The most potent MAO-A inhibitor, compound 10f, had an IC50 value of 3.805 μM. Some structure-activity relationships were derived, for example; it was concluded that heterocyclic substitution with 5-methyl-thiophene ring resulted in optimal hMAO-B inhibition, while pyrrole substitution was less favourable. Further investigation is however required as this is only a preliminary study. Reversibility studies: To determine the reversibility of binding, the recovery of enzymatic activity after dilution of the enzyme inhibitor complexes were determined for selected compounds. Results indicated that the most potent MAO-A inhibitor, the pyrrole derivative 10f, had a reversible mode of binding to both the hMAO-B and hMAO-A isoforms, since the enzyme activities were completely recovered by dilution of the inhibitor concentration. In contrast, enzyme activity was only partially recovered after dilution of the most potent MAO-B inhibitor 10i, indicating that this methylthiophene derivative possibly exhibited tight binding to the hMAO-B isoform, and the inhibition caused by this compound was not readily reversed by dilution. In order to determine whether the tight binding as exhibited by compound 10i was due to the thiophene or phenyl moieties, reversibility of binding was also determined for the pyrrole derivative 10e. The results showed that 10e had a reversible mode of binding to the hMAO-B isoform, and enzyme activity was completely recovered by dilution of the inhibitor. Based on these results, it was concluded that the tight binding as exhibited by compound 10i was due to the presence of the thiophene moiety. To confirm that compound 10i exhibited tight, and not irreversible binding, reversibility of binding was also determined by dialysis of enzyme-inhibitor mixtures. For this purpose hMAO-B and 10i, at a concentration of 4 × IC50, were preincubated for a period of 15 min and subsequently dialyzed for 24 h. The results of this study showed that 10i had a reversible mode of binding for MAO-B, since enzyme activity was recovered to a level of 83% after dialysis. Mode of inhibition: To determine the mode of inhibition of compound 10f, Lineweaver-Burk plots were constructed for the inhibition of hMAO-A and hMAO-B. The lines of the Lineweaver-Burk plots intersected at a single point at the y-axis, indicating that 10f had a competitive mode of binding to both hMAO-B and hMAO-A isoforms. MTT viability assay: To determine the toxicity of the chalcones for cultured cells, selected compounds were evaluated with the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) viability assay. The cytotoxicity of the test compounds were evaluated at concentrations of 1 and 10 μM, in HeLa cells. The results indicated that compound 10i was non-toxic at 1 and 10 μM, with 100% and 96% cell viability remaining after 24 h exposure of the compound to the cultured cells. Compound 10f, however, exhibited significant toxicity at 10 μM, with only 5% viable cells remaining. In contrast, compound 10e, with the same pyrrole moiety as 10f, was non-toxic at 1 μM and 10 μM, with 99% and 98%, cell viability remaining. It was concluded that the pyrrole moiety of 10f was not responsible for its higher degree of cytotoxicity, which suggests that the CF3 substituent may play a role in the higher degree of cytotoxicity observed for 10f. Further investigation is required to determine the mode of cytotoxicity, when cultured cells are exposed to 10f. Docking Studies: To complete this study and rationalise the results of the MAO inhibition studies, molecular modelling was carried out and all compounds were docked into the crystal structure of hMAO-B, by using the CDOCKER module of Discovery Studio. Some insights were obtained regarding the binding of compound 10i. This compound bound to MAO-B with the phenyl ring facing the FAD cofactor. This orientation allowed for the formation of pi-pi interaction with Tyr 398 as well as a pi-sigma interaction between the thiophene ring and Ile 199 (which is part of the gating switch of MAO-B). It is speculated that the tight binding component of hMAO-B inhibition by 10i may, at least in part, be attributed to the interaction of this compound with the gating switch amino acid, Ile 199. The docking results also showed that most compounds interacted with Tyr 326 or Tyr 398, while interactions with Cys 172, Gln 206, Ile 199 and Tyr 435 also occurred. In conclusion, novel heterocyclic chalcone analogues with promising MAO-B inhibitory activities were successfully synthesized and evaluated. / MSc (Pharmaceutical Chemistry) North-West University, Potchefstroom Campus, 2014

Parkinson’s disease (PD) is an age related neurodegenerative disorder that presents with both motor and non-motor symptoms. The most common pathological characteristic of PD is the loss of the pigmented dopaminergic neurons of the substantia nigra pars compacta (SNpc), with the appearance of intracellular inclusions known as Lewy bodies in the affected neurons. The loss of the SNpc neurons results in a deficiency of dopamine in the nigrostriatal pathway of the brain, and it is this deficiency that is responsible for the motor symptoms of PD. Monoamine oxidase B (MAO-B) is predominantly found in the striatum and is responsible for the oxidative metabolism of dopamine. The first-line treatment of PD is dopamine replacement therapy with levodopa, the metabolic precursor of dopamine. Rapid metabolism of levodopa at central and peripheral level, however, hampers its therapeutic potential. MAO-B inhibition enhances striatal dopamine activity by means of inhibiting dopamine metabolism, and MAO-B inhibitors are thus used in the treatment of PD, particularly in combination with levodopa. The aim of this study was to design new potent, reversible MAO inhibitors with selectivity towards MAO-B for the symptomatic treatment of PD. Recent studies have shown that C5-substituted phthalide derivatives are highly potent inhibitors of human MAO-B. Phthalide derivatives were also found to be potent inhibitors of human MAO-A. The structural similarity between phthalide and 3-coumaranone suggests that 3-coumaranone may be a useful scaffold for the design of reversible MAO-B inhibitors. In the present study, 3-coumaranone derivatives were thus synthesised and evaluated as potential MAO-A and MAO-B inhibitors. By reacting 6-hydroxy-3-coumaranone with the appropriate alkylbromide in N,N-dimethylformamide in the presence of potassium carbonate, a series of twenty 3-coumaranone derivatives were synthesised. The structures of the compounds were verified with NMR spectroscopy and mass spectrometry. The purities of the compounds were determined by HPLC analyses. To determine the inhibition potencies, the recombinant human MAO-A and MAO-B enzymes were used, and the inhibition potencies were expressed as IC50 values. The results indicated that the 3-coumaranone derivatives are highly potent MAO-B inhibitors. For example, 9 of the 3-coumaranone derivatives inhibited MAO-B with IC50 values < 0.05 μM, with the most potent inhibitor exhibiting an IC50 value of 0.004 μM. Although the 3-coumaranone derivatives are selective MAO-B inhibitors, some compounds were also potent MAO-A inhibitors with the most potent inhibitor exhibiting an IC50 value of 0.586 μM. The reversibility of MAO-B inhibition by a representative inhibitor was examined by measuring the degree to which the enzyme activity recovers after dialysis of the enzyme-inhibitor complex. Since MAO-B activity was almost completely recovered after dialysis, it may be concluded that the 3-coumaranone derivatives bind reversibly to MAO-B. Lineweaver-Burk plots were constructed to show that the representative 3-coumaranone derivative is a competitive inhibitor of MAO-B. To conclude, the 3-coumaranone derivatives are potent, selective, reversible and competitive inhibitors of MAO-B. These compounds may find application in the treatment of neurodegenerative disorders such as PD. Potent MAO-A inhibitors were also discovered, which suggests that 3-coumaranone derivatives may serve as leads for the design of drugs for the treatment of depression. In addition, 3-coumaranone derivatives which inhibited both MAO-A and MAO-B, may have potential application in the therapy of both PD and depressive illness. / MSc (Pharmaceutical Chemistry), North-West University, Potchefstroom Campus, 2015

Parkinson’s disease is the second most common age-related neurodegenerative disease after Alzheimer’s disease. The characteristic pathological feature of Parkinson’s disease is the loss of neurons in the substantia nigra pars compacta (SNpc), which leads to a striatal dopamine deficiency responsible for the major symptoms of Parkinson’s disease. These symptoms include tremor at rest, postural instability, bradykinesia and in the later stages of Parkinson’s disease, even psychosis. Presently, there is still no cure for Parkinson’s disease and all treatments are only symptomatic. Current research is therefore directed towards the prevention of further dopaminergic neurodegeneration, while the ultimate aim is the reversal of neurodegeneration. Monoamine oxidase (MAO) enzymes are responsible for the regulation and metabolism of monoamine neurotransmitters, such as dopamine. There are two MAO isoforms, MAO-A and MAO-B. Since MAO-B has greater activity in the basal ganglia, it is of particular importance in movement disorders, which include Parkinson’s disease. The selective inhibition of MAO-B, increases dopamine available for binding, and thus reduces Parkinson’s disease symptoms. MAO inhibitors also have neuroprotective potential and thus may slow down, halt and even reverse neurodegeneration in Parkinson’s disease. It is still unclear exactly how MAO inhibitors protect neurons, but one theory suggests that MAO inhibition decreases oxidative stress by reducing the formation of hydrogen peroxide, a metabolic by-product of MAO oxidation of monoamines. Normally, hydrogen peroxide is inactivated by glutathione (GSH), however, in Parkinson’s disease, GSH levels are low, resulting in the accumulation of hydrogen peroxide, which then becomes available for the Fenton reaction. In the Fenton reaction, Fe2+ reacts with hydrogen peroxide and generates an active free radical, the hydroxyl radical. This radical depletes cellular anti-oxidants, damage lipids, proteins and DNA. MAO inhibitors reduce the formation of hydrogen peroxide thus decreasing the formation of hydroxyl radicals and oxidative stress. The MAO inhibitory potential of natural and synthetic chalcones have been illustrated. For example, in 1987, Tanaka and co-workers determined that natural chalcones, such as isoliquiritigenin, have MAO inhibitory activity in rat mitochondria. In 2009, Chimenti and co-workers synthesized a series of 1,3-diphenyl-2-propen-1-ones which exhibited human MAO-B (hMAO-B) selective inhibitory activity. On the other hand, Robinson and co-workers (2013), synthesized novel furanochalcones which also had hMAO-B selective inhibitory activity. A reversible, competitive mode of binding was demonstrated by these compounds. Since the effect of heterocyclic substitution, other than furan on the MAO inhibitory properties of the chalcone scaffold remains unexplored, the aim of this study was to synthesize and evaluate further heterocyclic chalcone analogues as inhibitors of hMAO. RESULTS Design and synthesis: Heterocyclic chalcone analogues that incorporated pyrrole, 5- methylthiophene, 5-chlorothiophene and 2-methoxypyridine substitution were synthesized using the Claisen-Schmidt condensation reaction. All compounds were characterized with 1H-NMR, 13CNMR, IR, MS, and melting points were recorded. Purity was determined with HPLC analysis. MAO inhibition studies: The 50% inhibitory concentration (IC50) values and selectivity index (SI) of all compounds were determined using a fluorometric assay and kynuramine as substrate. Eight out of the ten synthesized compounds exhibited IC50 values < 1 μM, and can thus be considered as potent MAO-B inhibitors, while all compounds showed selectivity for the MAO-B isoform. Compound 10i was the most potent MAO-B inhibitor with an IC50 value of 0.067 μM and the highest SI of 240.7. The most potent MAO-A inhibitor, compound 10f, had an IC50 value of 3.805 μM. Some structure-activity relationships were derived, for example; it was concluded that heterocyclic substitution with 5-methyl-thiophene ring resulted in optimal hMAO-B inhibition, while pyrrole substitution was less favourable. Further investigation is however required as this is only a preliminary study. Reversibility studies: To determine the reversibility of binding, the recovery of enzymatic activity after dilution of the enzyme inhibitor complexes were determined for selected compounds. Results indicated that the most potent MAO-A inhibitor, the pyrrole derivative 10f, had a reversible mode of binding to both the hMAO-B and hMAO-A isoforms, since the enzyme activities were completely recovered by dilution of the inhibitor concentration. In contrast, enzyme activity was only partially recovered after dilution of the most potent MAO-B inhibitor 10i, indicating that this methylthiophene derivative possibly exhibited tight binding to the hMAO-B isoform, and the inhibition caused by this compound was not readily reversed by dilution. In order to determine whether the tight binding as exhibited by compound 10i was due to the thiophene or phenyl moieties, reversibility of binding was also determined for the pyrrole derivative 10e. The results showed that 10e had a reversible mode of binding to the hMAO-B isoform, and enzyme activity was completely recovered by dilution of the inhibitor. Based on these results, it was concluded that the tight binding as exhibited by compound 10i was due to the presence of the thiophene moiety. To confirm that compound 10i exhibited tight, and not irreversible binding, reversibility of binding was also determined by dialysis of enzyme-inhibitor mixtures. For this purpose hMAO-B and 10i, at a concentration of 4 × IC50, were preincubated for a period of 15 min and subsequently dialyzed for 24 h. The results of this study showed that 10i had a reversible mode of binding for MAO-B, since enzyme activity was recovered to a level of 83% after dialysis. Mode of inhibition: To determine the mode of inhibition of compound 10f, Lineweaver-Burk plots were constructed for the inhibition of hMAO-A and hMAO-B. The lines of the Lineweaver-Burk plots intersected at a single point at the y-axis, indicating that 10f had a competitive mode of binding to both hMAO-B and hMAO-A isoforms. MTT viability assay: To determine the toxicity of the chalcones for cultured cells, selected compounds were evaluated with the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) viability assay. The cytotoxicity of the test compounds were evaluated at concentrations of 1 and 10 μM, in HeLa cells. The results indicated that compound 10i was non-toxic at 1 and 10 μM, with 100% and 96% cell viability remaining after 24 h exposure of the compound to the cultured cells. Compound 10f, however, exhibited significant toxicity at 10 μM, with only 5% viable cells remaining. In contrast, compound 10e, with the same pyrrole moiety as 10f, was non-toxic at 1 μM and 10 μM, with 99% and 98%, cell viability remaining. It was concluded that the pyrrole moiety of 10f was not responsible for its higher degree of cytotoxicity, which suggests that the CF3 substituent may play a role in the higher degree of cytotoxicity observed for 10f. Further investigation is required to determine the mode of cytotoxicity, when cultured cells are exposed to 10f. Docking Studies: To complete this study and rationalise the results of the MAO inhibition studies, molecular modelling was carried out and all compounds were docked into the crystal structure of hMAO-B, by using the CDOCKER module of Discovery Studio. Some insights were obtained regarding the binding of compound 10i. This compound bound to MAO-B with the phenyl ring facing the FAD cofactor. This orientation allowed for the formation of pi-pi interaction with Tyr 398 as well as a pi-sigma interaction between the thiophene ring and Ile 199 (which is part of the gating switch of MAO-B). It is speculated that the tight binding component of hMAO-B inhibition by 10i may, at least in part, be attributed to the interaction of this compound with the gating switch amino acid, Ile 199. The docking results also showed that most compounds interacted with Tyr 326 or Tyr 398, while interactions with Cys 172, Gln 206, Ile 199 and Tyr 435 also occurred. In conclusion, novel heterocyclic chalcone analogues with promising MAO-B inhibitory activities were successfully synthesized and evaluated. / MSc (Pharmaceutical Chemistry) North-West University, Potchefstroom Campus, 2014

Parkinson’s disease (PD) is an age related neurodegenerative disorder that presents with both motor and non-motor symptoms. The most common pathological characteristic of PD is the loss of the pigmented dopaminergic neurons of the substantia nigra pars compacta (SNpc), with the appearance of intracellular inclusions known as Lewy bodies in the affected neurons. The loss of the SNpc neurons results in a deficiency of dopamine in the nigrostriatal pathway of the brain, and it is this deficiency that is responsible for the motor symptoms of PD. Monoamine oxidase B (MAO-B) is predominantly found in the striatum and is responsible for the oxidative metabolism of dopamine. The first-line treatment of PD is dopamine replacement therapy with levodopa, the metabolic precursor of dopamine. Rapid metabolism of levodopa at central and peripheral level, however, hampers its therapeutic potential. MAO-B inhibition enhances striatal dopamine activity by means of inhibiting dopamine metabolism, and MAO-B inhibitors are thus used in the treatment of PD, particularly in combination with levodopa. The aim of this study was to design new potent, reversible MAO inhibitors with selectivity towards MAO-B for the symptomatic treatment of PD. Recent studies have shown that C5-substituted phthalide derivatives are highly potent inhibitors of human MAO-B. Phthalide derivatives were also found to be potent inhibitors of human MAO-A. The structural similarity between phthalide and 3-coumaranone suggests that 3-coumaranone may be a useful scaffold for the design of reversible MAO-B inhibitors. In the present study, 3-coumaranone derivatives were thus synthesised and evaluated as potential MAO-A and MAO-B inhibitors. By reacting 6-hydroxy-3-coumaranone with the appropriate alkylbromide in N,N-dimethylformamide in the presence of potassium carbonate, a series of twenty 3-coumaranone derivatives were synthesised. The structures of the compounds were verified with NMR spectroscopy and mass spectrometry. The purities of the compounds were determined by HPLC analyses. To determine the inhibition potencies, the recombinant human MAO-A and MAO-B enzymes were used, and the inhibition potencies were expressed as IC50 values. The results indicated that the 3-coumaranone derivatives are highly potent MAO-B inhibitors. For example, 9 of the 3-coumaranone derivatives inhibited MAO-B with IC50 values < 0.05 μM, with the most potent inhibitor exhibiting an IC50 value of 0.004 μM. Although the 3-coumaranone derivatives are selective MAO-B inhibitors, some compounds were also potent MAO-A inhibitors with the most potent inhibitor exhibiting an IC50 value of 0.586 μM. The reversibility of MAO-B inhibition by a representative inhibitor was examined by measuring the degree to which the enzyme activity recovers after dialysis of the enzyme-inhibitor complex. Since MAO-B activity was almost completely recovered after dialysis, it may be concluded that the 3-coumaranone derivatives bind reversibly to MAO-B. Lineweaver-Burk plots were constructed to show that the representative 3-coumaranone derivative is a competitive inhibitor of MAO-B. To conclude, the 3-coumaranone derivatives are potent, selective, reversible and competitive inhibitors of MAO-B. These compounds may find application in the treatment of neurodegenerative disorders such as PD. Potent MAO-A inhibitors were also discovered, which suggests that 3-coumaranone derivatives may serve as leads for the design of drugs for the treatment of depression. In addition, 3-coumaranone derivatives which inhibited both MAO-A and MAO-B, may have potential application in the therapy of both PD and depressive illness. / MSc (Pharmaceutical Chemistry), North-West University, Potchefstroom Campus, 2015

Many patients suffer from dermatological diseases throughout the world. Literature about this problem is emphasizing that it is getting worse. Factors such as poor hygiene, poverty and diseases such as HIV/AIDS, have increased the prevalence of dermatological diseases in developing countries such as Namibia. Understanding the different dermatological diseases and studying their prevalence will aid in ensuring patients better quality of life. The aim of the study was to investigate the prevalence and medicinal treatment patterns of dermatological diseases in the private healthcare sector of Namibia, with special reference to Windhoek. The research methodology was divided into two sections, namely a literature analysis and an empirical study. The literature analysis has been done to ensure knowledge about dermatological conditions before the empirical study was started. The empirical study was divided into two phases and data were collected from the community pharmacy environment (Phase 1) and a dermatologist (Phase 2). A total number of 507 patients participated in this study. In the community pharmacy environment, data were gathered from dermatological prescriptions of general practitioners (Phase 1A) and from pharmacist-initiated therapy prescriptions (Phase 1B). The data collected from the dermatologist (Phase 2), were collected from patients files at the dermatologist‘s practise. Phase 1A indicated that urticaria (n=36) had the highest prevalence followed by eczema (n=28) and contact dermatitis (n=28). 49% of the patients that participated in this phase were seeking treatment for the same condition the second time. In Phase 1B, contact dermatitis (n=15) showed the highest prevalence with eczema (n=14) and urticaria (n=8) second and third respectively. 77% of the patients participating in this phase of the research study did not have a family history of the same dermatological diseases. Phase 2 indicated that the highest prevalence of dermatological diseases was acne vulgaris (n=30) and melasma (n=19). The treatment duration that occurred most often in this phase was 180 days. Over all, the data indicated that eczema was the dermatological disease with the highest incidence of 11.2% (n=57). Other diseases that played a significant part were acne vulgaris (10.5%), urticaria (9.0%), contact dermatitis (8.6%) and melasma (7.1%). Rare dermatological diseases such as Kaposi sarcoma showed relatively high prevalence (n=9). It was concluded that this could be due to the fact that the dermatologist consulted, had been the only dermatologist claiming directly from the government medical aid, and that most of the patients diagnosed with Kaposi sarcoma during this research study were government employees. Many dermatological diseases were not specifically defined or diagnosed, but still treated with topical corticosteroids which may suggest that the term eczema is undefined and easily used by different healthcare practitioners for dry-skin related conditions. It is concluded in this research study that the three most prevalent dermatological diseases in the private healthcare sector of Namibia are eczema, acne vulgaris and urticaria. These conditions are not considered to be life-threatening, but they do have a significant effect on the quality of life of patients. / MPham (Pharmacy Practice), North-West University, Potchefstroom Campus, 2014

Many patients suffer from dermatological diseases throughout the world. Literature about this problem is emphasizing that it is getting worse. Factors such as poor hygiene, poverty and diseases such as HIV/AIDS, have increased the prevalence of dermatological diseases in developing countries such as Namibia. Understanding the different dermatological diseases and studying their prevalence will aid in ensuring patients better quality of life. The aim of the study was to investigate the prevalence and medicinal treatment patterns of dermatological diseases in the private healthcare sector of Namibia, with special reference to Windhoek. The research methodology was divided into two sections, namely a literature analysis and an empirical study. The literature analysis has been done to ensure knowledge about dermatological conditions before the empirical study was started. The empirical study was divided into two phases and data were collected from the community pharmacy environment (Phase 1) and a dermatologist (Phase 2). A total number of 507 patients participated in this study. In the community pharmacy environment, data were gathered from dermatological prescriptions of general practitioners (Phase 1A) and from pharmacist-initiated therapy prescriptions (Phase 1B). The data collected from the dermatologist (Phase 2), were collected from patients files at the dermatologist‘s practise. Phase 1A indicated that urticaria (n=36) had the highest prevalence followed by eczema (n=28) and contact dermatitis (n=28). 49% of the patients that participated in this phase were seeking treatment for the same condition the second time. In Phase 1B, contact dermatitis (n=15) showed the highest prevalence with eczema (n=14) and urticaria (n=8) second and third respectively. 77% of the patients participating in this phase of the research study did not have a family history of the same dermatological diseases. Phase 2 indicated that the highest prevalence of dermatological diseases was acne vulgaris (n=30) and melasma (n=19). The treatment duration that occurred most often in this phase was 180 days. Over all, the data indicated that eczema was the dermatological disease with the highest incidence of 11.2% (n=57). Other diseases that played a significant part were acne vulgaris (10.5%), urticaria (9.0%), contact dermatitis (8.6%) and melasma (7.1%). Rare dermatological diseases such as Kaposi sarcoma showed relatively high prevalence (n=9). It was concluded that this could be due to the fact that the dermatologist consulted, had been the only dermatologist claiming directly from the government medical aid, and that most of the patients diagnosed with Kaposi sarcoma during this research study were government employees. Many dermatological diseases were not specifically defined or diagnosed, but still treated with topical corticosteroids which may suggest that the term eczema is undefined and easily used by different healthcare practitioners for dry-skin related conditions. It is concluded in this research study that the three most prevalent dermatological diseases in the private healthcare sector of Namibia are eczema, acne vulgaris and urticaria. These conditions are not considered to be life-threatening, but they do have a significant effect on the quality of life of patients. / MPham (Pharmacy Practice), North-West University, Potchefstroom Campus, 2014

Asthma is a chronic disease of the airways and affects many people regardless of their age, gender, race and socioeconomic status. Since asthma is recognised as one of the major causes of morbidity and mortality in people and especially in South Africa, the prescribing patterns, prevalence and medication cost of asthma in South Africa are saliently important and need to be investigated. A non-experimental, quantitative retrospective drug utilisation review was conducted on medicine claims data of a pharmaceutical benefit management company in a section of the private health care sector of South Africa. The study period was divided into four annual time periods (1 January 2008 to 31 December 2008, 1 January 2009 to 31 December 2009, 1 January 2010 to 31 December 2010 and 1 January 2011 to 31 December 2011). The prescribing patterns and cost of asthma medication were investigated and stratified according to province, age and gender. Patients were included if the prescriptions which were provided by the health care practitioners matched the Chronic Disease List (CDL) of South Africa and the International Classification of Disease (ICD-10) coding for asthma and chronic obstructive pulmonary disease (COPD). Data analysis was conducted by means of the SAS 9.3® computer package. Asthma patients were divided according to different age groups (there were five different age groups for this study), gender and geographical areas of South Africa. The study indicated a steady increase in the prevalence of asthma patients from 0.82% (n = 7949) in 2008 to 1.18% (n = 15 423) in 2009 and reached a minimum of 0.79% (n = 8554) in 2011. Analysis of the prevalence regarding geographical areas in South Africa suggested that Gauteng had the highest number [n = 17 696, (0.85%)] of asthma patients throughout the study period, followed by KwaZulu Natal [n = 8 628, 1.16%)] and the Western Cape [(n = 8513, 0.97%) (p < 0.05)]. The prevalence of asthma in female patients [0.89% (n = 26 588)] was higher than in their male counterparts [0.79% (n = 19 244)] (p > 0.05). The results showed that asthma was not as common chronic disease in children. The total number of asthma patients younger than 7 years represented 0.64% (n = 2 909). It was found that patients over 65 years of age showed the highest prevalence of the five age groups [1.94% (n = 13 403) (p < 0.05)]. The average number of asthma prescriptions per patient per year was 8.28 (95% CI, 8.16- 8.40) and 5.15 (95% CI, 5.06-5.23) in 2008 and 2011, respectively. The number of asthma items per prescription varied from 1.55 (95% CI, 1.55-1.56) in 2008 to 1.40 (95% CI, 1.39- 1.40) in 2011. Medication from the MIMS® pharmacological group (anti-asthmatics and bronchodilators) was used to identify asthma medication. The top three asthma medication with the highest prevalence in the study period were the anti-inflammatory inhaler of fluticasone (n = 39 721) followed by the single item combination product of budesonide/ formoterol (n = 25 121) and salbutamol (n = 24 296). The influence of COPD on asthma treatment and the costimplication thereof were investigated. Medication from the MIMS® pharmacological group (anti-asthmatics and bronchodilators) was used to identify COPD medication. This study also showed that COPD had an influence in the economic burden of the South African asthma population. The cost of medication is responsible for the single largest direct cost involved in the economic burden of asthma. This study showed that asthma represented 0.88% of the direct medication cost in the study (excluding hospitalisation and indirect cost). The average cost per prescription and average cost per asthma item both increased throughout the study period. The prescribing patterns for the different medication used in the treatment of asthma were investigated and recommendations for further research in this field of study were made. / MPharm (Pharmacy Practice), North-West University, Potchefstroom Campus, 2014

Aims of this project - The aim of this study was to design and synthesise novel 2-aminopyrimidine derivatives as potential adenosine A1 and A2A receptor antagonists. Background and rationale - Parkinson’s disease is the second most common neurodegenerative disorder (after Alzheimer’s disease) and is characterised by the selective death of the dopaminergic neurons of the nigro-striatal pathway. Distinctive motor symptoms include bradykinesia, muscle rigidity and tremor, while non-motor symptoms, of which cognitive dysfunction is an example, also frequently occur. Current therapy provides symptomatic relief mainly by augmentation of dopaminergic signalling (levodopa, dopamine agonists, MAO and COMT enzyme inhibitors), but disease progression is not adequately addressed. New therapies that can prevent further neurodegeneration in addition to providing symptomatic relief are therefore urgently required. Adenosine has an important function as neuromodulator in the central nervous system. The adenosine A2A receptor in particular plays an essential role in the regulation of movement. This, coupled to the fact that it is uniquely distributed in the basal ganglia, contributes to its attractiveness as non-dopaminergic target in the treatment of movement disorders, such as Parkinson’s disease. The efficacy of adenosine receptor antagonists has been illustrated in animal models of Parkinson’s disease and several adenosine receptor antagonists have also reached clinical trials. The neuroprotective properties of adenosine A2A receptor antagonists are further attributed to their ability to modulate neuro-inflammation and decrease the release of the excitatory neurotransmitter glutamate, which is implicated in neurotoxicity. While adenosine A1 receptor antagonism has a synergistic effect on the motor effects of adenosine A2A receptor antagonism, it has the additional benefit of improving cognitive dysfunction, a cardinal non-motor symptom of Parkinson’s disease. Dual antagonism of adenosine A1 and A2A receptors therefore offers the potential of providing symptomatic relief as well as the neuroprotection so desperately needed in the clinical environment. Amino substituted heterocyclic scaffolds, such as those containing the 2-aminopyrimidine motif, have been shown to exhibit good efficacy as dual adenosine receptor antagonists. Since the structure activity relationships of 2-aminopyrimidines have not been comprehensively explored, it is in this regard that this study aimed to make a contribution. Results - Fourteen 2-aminopyrimidines were synthesised successfully over three steps, (although in low yields) and characterised by nuclear magnetic resonance and infrared spectroscopy, mass spectrometry, by determination of melting points and high performance liquid chromatography. Structure modifications explored included variation of the aromatic substituent on position 4, as well as variations in the substituents of the phenyl ring, present on position 6 of the pyrimidine ring. Radioligand binding assays were performed to determine the affinities of the synthesised compounds for the adenosine A1 and A2A receptor subtypes. Several high dual affinity derivatives were identified during this study; the compound with the highest affinity was 4-(5- methylthiophen-2-yl)-6-[3-(piperidine-1-carbonyl)phenyl]pyrimidin-2-amine (39f) with Ki values of 0.5 nM and 2.3 nM for the adenosine A2A and adenosine A1 receptors, respectively. A few general structure activity relationships were derived, which included: The effect of the aromatic substituent (position 4) on A2A affinity could be summarised (in order of declining affinity) as follows: 5-methylthiophene > phenyl > furan > pyridine > p-fluorophenyl > benzofuran. On the other hand, the effect of this substituent on A1 receptor affinity could be summarised (in order of declining affinity) as follows: phenyl > 5-methylthiophene > pfluorophenyl > benzofuran > pyridine. The affinities as exhibited by the methylthiophene derivatives 39f, 39h – 39j, further showed that while piperidine substitution (39f) resulted in optimal A2A and A1 affinity, pyrrolidine substitution (39j) was less favourable. Substitution at the 4ʹ position of the phenyl ring, as well as thiazole substitution, generally resulted in poor adenosine A1 and A2A receptor affinity. However, 4-[2-amino-6-(5-methylfuran-2-yl)pyrimidin- 4-yl]-N-(1,3-benzothiazol-2-yl)benzamide (39l) surprisingly demonstrated good affinity and selectivity for the adenosine A1 receptor. The results obtained during radioligand binding assays were rationalised by QSAR and molecular modelling (Discovery Studio 3.1, Accelrys) studies. The inverse relationship seen between log Ki (as indicator of affinity) and polar surface area, illustrated the importance of this physico-chemical property in the design of 2-aminopyrimidine A2A antagonists. The results from the docking study further showed that the orientation adopted by derivatives in the binding cavity (and particular hydrogen bonding to Asn 253 and Glu 169) is of importance. Results from the MTT cell viability assay indicated that none of the high affinity derivatives had a significant effect on cell viability at 1 μM, a concentration much higher than their Ki values. However, incorporation of the furan, benzofuran and p-fluorophenyl groups as aromatic substituent and a pyrrolidine as amine substituent, presented liabilities. Lastly, the haloperidol induced catalepsy assay (in rats) was used to give a preliminary indication of adenosine receptor antagonism or agonism. Compound 39f failed to reverse catalepsy under standard conditions, but showed some reversal after an increased time period. Indications therefore exist that 39f is an adenosine receptor antagonist that suffers from bioavailability issues. Compound (39c), 4-phenyl-6-[3-(piperidine-1- carbonyl)phenyl]pyrimidin-2-amine which also demonstrated promising affinity in the radioligand binding assays however showed a statistically significant reduction in catalepsy, indicating adenosine A2A receptor antagonism, and in vivo efficacy. Highly potent, dual affinity aminopyrimidine derivatives with acceptable toxicity profiles were identified in this study, with compound 39c demonstrating in vivo activity. The aim of designing and synthesising a promising dual adenosine A1/A2A receptor antagonist is therefore realised, with compound 39c as the most favourable example. / MSc (Pharmaceutical Chemistry), North-West University, Potchefstroom Campus, 2014