Antidiabetic and toxicological properties of Dianthus thunbergii (Caryophyllaceae) roots and Hypoxis argentea (Hypoxidaceae) corms
- Authors: Akinrinde, Akinleye Stephen
- Date: 2017
- Subjects: Medicinal plants--South Africa--Eastern Cape Traditional medicine--South Africa--Eastern Cape Diabetics--Alternative treatment--South Africa
- Language: English
- Type: Thesis , Doctoral , Biochemistry
- Identifier: http://hdl.handle.net/10353/16036 , vital:40606
- Description: Diabetes mellitus is a chronic metabolic disorder primarily characterized by elevated blood glucose levels. Its rapidly increasing prevalence as a major non-communicable disease is now a growing concern for both developed and developing countries. The development of safe, cost-effective and pharmacologically-effective medications continues to a major challenge of antidiabetic management. Since most conventional antidiabetic drugs are costly and present with numerous adverse effects, alternatives are increasingly being sought from natural sources, most notably medicinal plants, as viable approaches to tackling the scourge of this disease. In the Eastern Cape Province of South Africa, the roots of Dianthus thunbergii and corms of Hypoxis argentea are frequently used traditionally for the treatment of diabetes mellitus, although no scientific evidence exists to validate their effectiveness for diabetes management. The studies conducted in the resent research were, therefore, aimed at investigating the antidiabetic and toxicological properties of these plants, in an attempt to providing data towards validating their use in traditional management of diabetes mellitus. Aqueous and ethanol extracts of the underground parts of D. thunbergii and H. argentea were initially subjected to analysis of their phytochemical composition, relative to standard compounds, and the nature of their in-vitro antioxidant activities using standard spectrophotometric methods. The potentials of these extracts for cytotoxicity and/or cell proliferation were evaluated using MTT assay in HepG2 cells and Crystal violet assay in INS-1 cells. These activities were further examined in INS-1 cells using live cell fluorescence imaging techniques. To evaluate the antidiabetic properties of the extracts, they were screened for their inhibitory effects on the activities of different enzymes including α-amylase, α-glucosidase, porcine pancreatic lipase, Dipeptidyl peptidase IV (DPP-IV), collagenase and the drug metabolizing enzyme, CYP3A4, while also assessing their effects on protein glycation using in- vitro visible and fluorescence spectrophotometric approaches. Cell culture procedures were carried out to evaluate the effects of the extracts on glucose utilization in HepG2 cells and L6 myotubes; nitric oxide production in RAW 264.7 macrophages; glucose metabolism in INS-1 cells, as well as triglyceride accumulation in 3T3-L1 pre-adipocytes. Furthermore, identification of compounds present in the aqueous and ethanol extracts was carried out by Liquid chromatography- Mass spectrometry (LC-MS), while volatile oils extracted from fresh and dried parts of the two plants by hydrodistillation were also analyzed by Gas chromatography-Mass spectrometry (GC-MS). The ethanol extracts of both D. thunbergii and H. argentea contained higher amounts of total phenols, flavonoids, tannins, proanthocyanidins and alkaloids, when compared with the aqueous extracts. This finding was in direct correlation with the antioxidant activities of the extracts, with the ethanol extracts of both plants demonstrating stronger scavenging activities against hydrogen peroxide, nitric oxide, ABTS and DPPH radicals, while also exhibiting higher ferric reducing antioxidant potentials, when compared with the aqueous extracts, and in some cases, the standard antioxidants, Vitamin C, butylated hydroxytoluene and rutin. The aqueous extracts of D. thunbergii exhibited the highest toxicity in HepG2 cells with IC50 < 50 μg/ml, while also producing a concentration-dependent reduction in the viability of INS-1 cells up to 41.81percent at 50 μg/ml. Both extracts of H. argentea, however, did not produce any significant toxicity in these cells. Fluorescence imaging of live INS-1 cells using Hoechst and propidium iodide staining revealed stimulation of cell proliferation by H. argentea, while the cytotoxicity of D. thunbergii was further confirmed. H. argentea caused stimulation of glucose uptake in HepG2 cells up to 119.58 percent at 100 μg/ml and as much as 116.96 percent in L6 myotubes at 50 μg/ml, without showing toxicity to these cells. D. thunbergii produced 18.39 percent increase in L6 glucose uptake above untreated control; although its effect on HepG2 glucose uptake was irrelevant as significant toxicity was produced in these cells. H. argentea produced a concentration-dependent reduction in nitric oxide production in RAW macrophages, although not as effectively as the positive control, aminoguanidine. Again, the toxicity of D. thunbergii to this cell line precludes the relevance of nitric oxide inhibition as an antidiabetic mechanism for this plant. D. thunbergii produced a concentration-dependent increase in 3T3-L1 triglyceride accumulation, as measured by Oil red O staining, compared to untreated cells, while H. argentea exerted no significant alterations in pre- adipocyte differentiation. Generally, the two plants produced weak inhibition of the activities of the various enzymes measured, suggesting that this mechanism may not play a major role in the activities of these plants as possible antidiabetic agents. GC-MS analysis revealed major differences in the volatile oil composition between fresh and dried plant parts for both plants. Most notably, total terpenoid content of D. thunbergii oils reduced significantly from 77.17 percent in the fresh root oil to 47.58 percent in the dried root oil. Total terpenoid content was much lower in H. argentea oils, but similarly reduced from 10.58 percent in the fresh corm oil to 4.00 percent in the dried corm oil. LC-MS analysis enabled the tentative identification of compounds including phenolic glycosides, flavonoids, alkaloids, terpenoids saponins and sapogenins, many of which have been reported in literature to exert bioactivities relevant to the ones elucidated in the present study. Overall, H. argentea exhibited antidiabetic properties that may be mediated by its stimulation of glucose uptake in HepG2 and L6 cells; stimulation of proliferation in INS-1 cells; lack of stimulation of 3T3-L1 triglyceride accumulation and a tendency to reduce nitric oxide production in RAW macrophages. These activities suggest that H. argentea has promise for further investigations as an antidiabetic agent. On the contrary, D. thunbergii exhibited significant toxicity to HepG2 cells, INS-1 cells and RAW macrophages. Its cytotoxicity at the concentrations investigated in the present studies raises significant concerns about any potential antidiabetic applications for this plant.
- Full Text:
- Date Issued: 2017
- Authors: Akinrinde, Akinleye Stephen
- Date: 2017
- Subjects: Medicinal plants--South Africa--Eastern Cape Traditional medicine--South Africa--Eastern Cape Diabetics--Alternative treatment--South Africa
- Language: English
- Type: Thesis , Doctoral , Biochemistry
- Identifier: http://hdl.handle.net/10353/16036 , vital:40606
- Description: Diabetes mellitus is a chronic metabolic disorder primarily characterized by elevated blood glucose levels. Its rapidly increasing prevalence as a major non-communicable disease is now a growing concern for both developed and developing countries. The development of safe, cost-effective and pharmacologically-effective medications continues to a major challenge of antidiabetic management. Since most conventional antidiabetic drugs are costly and present with numerous adverse effects, alternatives are increasingly being sought from natural sources, most notably medicinal plants, as viable approaches to tackling the scourge of this disease. In the Eastern Cape Province of South Africa, the roots of Dianthus thunbergii and corms of Hypoxis argentea are frequently used traditionally for the treatment of diabetes mellitus, although no scientific evidence exists to validate their effectiveness for diabetes management. The studies conducted in the resent research were, therefore, aimed at investigating the antidiabetic and toxicological properties of these plants, in an attempt to providing data towards validating their use in traditional management of diabetes mellitus. Aqueous and ethanol extracts of the underground parts of D. thunbergii and H. argentea were initially subjected to analysis of their phytochemical composition, relative to standard compounds, and the nature of their in-vitro antioxidant activities using standard spectrophotometric methods. The potentials of these extracts for cytotoxicity and/or cell proliferation were evaluated using MTT assay in HepG2 cells and Crystal violet assay in INS-1 cells. These activities were further examined in INS-1 cells using live cell fluorescence imaging techniques. To evaluate the antidiabetic properties of the extracts, they were screened for their inhibitory effects on the activities of different enzymes including α-amylase, α-glucosidase, porcine pancreatic lipase, Dipeptidyl peptidase IV (DPP-IV), collagenase and the drug metabolizing enzyme, CYP3A4, while also assessing their effects on protein glycation using in- vitro visible and fluorescence spectrophotometric approaches. Cell culture procedures were carried out to evaluate the effects of the extracts on glucose utilization in HepG2 cells and L6 myotubes; nitric oxide production in RAW 264.7 macrophages; glucose metabolism in INS-1 cells, as well as triglyceride accumulation in 3T3-L1 pre-adipocytes. Furthermore, identification of compounds present in the aqueous and ethanol extracts was carried out by Liquid chromatography- Mass spectrometry (LC-MS), while volatile oils extracted from fresh and dried parts of the two plants by hydrodistillation were also analyzed by Gas chromatography-Mass spectrometry (GC-MS). The ethanol extracts of both D. thunbergii and H. argentea contained higher amounts of total phenols, flavonoids, tannins, proanthocyanidins and alkaloids, when compared with the aqueous extracts. This finding was in direct correlation with the antioxidant activities of the extracts, with the ethanol extracts of both plants demonstrating stronger scavenging activities against hydrogen peroxide, nitric oxide, ABTS and DPPH radicals, while also exhibiting higher ferric reducing antioxidant potentials, when compared with the aqueous extracts, and in some cases, the standard antioxidants, Vitamin C, butylated hydroxytoluene and rutin. The aqueous extracts of D. thunbergii exhibited the highest toxicity in HepG2 cells with IC50 < 50 μg/ml, while also producing a concentration-dependent reduction in the viability of INS-1 cells up to 41.81percent at 50 μg/ml. Both extracts of H. argentea, however, did not produce any significant toxicity in these cells. Fluorescence imaging of live INS-1 cells using Hoechst and propidium iodide staining revealed stimulation of cell proliferation by H. argentea, while the cytotoxicity of D. thunbergii was further confirmed. H. argentea caused stimulation of glucose uptake in HepG2 cells up to 119.58 percent at 100 μg/ml and as much as 116.96 percent in L6 myotubes at 50 μg/ml, without showing toxicity to these cells. D. thunbergii produced 18.39 percent increase in L6 glucose uptake above untreated control; although its effect on HepG2 glucose uptake was irrelevant as significant toxicity was produced in these cells. H. argentea produced a concentration-dependent reduction in nitric oxide production in RAW macrophages, although not as effectively as the positive control, aminoguanidine. Again, the toxicity of D. thunbergii to this cell line precludes the relevance of nitric oxide inhibition as an antidiabetic mechanism for this plant. D. thunbergii produced a concentration-dependent increase in 3T3-L1 triglyceride accumulation, as measured by Oil red O staining, compared to untreated cells, while H. argentea exerted no significant alterations in pre- adipocyte differentiation. Generally, the two plants produced weak inhibition of the activities of the various enzymes measured, suggesting that this mechanism may not play a major role in the activities of these plants as possible antidiabetic agents. GC-MS analysis revealed major differences in the volatile oil composition between fresh and dried plant parts for both plants. Most notably, total terpenoid content of D. thunbergii oils reduced significantly from 77.17 percent in the fresh root oil to 47.58 percent in the dried root oil. Total terpenoid content was much lower in H. argentea oils, but similarly reduced from 10.58 percent in the fresh corm oil to 4.00 percent in the dried corm oil. LC-MS analysis enabled the tentative identification of compounds including phenolic glycosides, flavonoids, alkaloids, terpenoids saponins and sapogenins, many of which have been reported in literature to exert bioactivities relevant to the ones elucidated in the present study. Overall, H. argentea exhibited antidiabetic properties that may be mediated by its stimulation of glucose uptake in HepG2 and L6 cells; stimulation of proliferation in INS-1 cells; lack of stimulation of 3T3-L1 triglyceride accumulation and a tendency to reduce nitric oxide production in RAW macrophages. These activities suggest that H. argentea has promise for further investigations as an antidiabetic agent. On the contrary, D. thunbergii exhibited significant toxicity to HepG2 cells, INS-1 cells and RAW macrophages. Its cytotoxicity at the concentrations investigated in the present studies raises significant concerns about any potential antidiabetic applications for this plant.
- Full Text:
- Date Issued: 2017
Nonlinear optical behavior of lanthanide phthalocyanines and their conjugates with a selection of nanomaterials
- Authors: Sekhosana, Kutloano Edward
- Date: 2017
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: http://hdl.handle.net/10962/4580 , vital:20695
- Description: This thesis presents novel asymmetrical and symmetrical lanthanide phthalocyanines (Pcs) characterized using a number techniques including proton nuclear magnetic resonance, electron spin resonance, time correlated single photon counting, FTIR spectrometry, MALDI-TOF mass spectrometry, UV-Vis spectrometry, Raman spectroscopy and CHNS elemental analysis. The design of theses lanthanide Pcs takes the form of mononuclear, binuclear, trinuclear, bis- and tris(phthalocyanines). Nanomaterials such as zinc oxide nanoparticles (ZnO NPs), multi-walled carbon nanotubes (MWCNTs) and graphene oxide nanosheets (GONS) (oxidized and reduced) were employed for covalent linkage to mono- and binuclear phthalocyanines as conjugates. Transmission electron microscopy was used to characterize ZnO NPs, MWCNTs and GONS alone and when linked to lanthanide Pcs. Lanthanide Pcs alone and when linked to ZnO NPs, MWCNTs and GONS where embedded in polymers such as poly (methyl methacrylate) (PMMA), poly (bisphenol A carbonate) (PBC) and poly (acrylic acid) (PAA) for thin film preparation. The thickness of the thin films was determined by utilization of the knife edge attachment of the A Bruker D8 Discover X-ray diffraction (XRD). Optical limiting properties of lanthanide Pcs alone and as conjugates in solution and when incorporated into polymers were determined by employing a Z-scan technique. It emerged that low symmetry lanthanide Pcs (19, 20 and 21), the blue forms of bis(phthalocyanines) (only in solution; 24 and 28) as well as tris(phthalocyanines) (30 and 31) exhibit low limiting threshold (Ilim) values in solution and thin films (particularly PBC and PAA). The low limiting threshold values make these lanthanide Pcs reliable optical limiters.
- Full Text:
- Date Issued: 2017
- Authors: Sekhosana, Kutloano Edward
- Date: 2017
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: http://hdl.handle.net/10962/4580 , vital:20695
- Description: This thesis presents novel asymmetrical and symmetrical lanthanide phthalocyanines (Pcs) characterized using a number techniques including proton nuclear magnetic resonance, electron spin resonance, time correlated single photon counting, FTIR spectrometry, MALDI-TOF mass spectrometry, UV-Vis spectrometry, Raman spectroscopy and CHNS elemental analysis. The design of theses lanthanide Pcs takes the form of mononuclear, binuclear, trinuclear, bis- and tris(phthalocyanines). Nanomaterials such as zinc oxide nanoparticles (ZnO NPs), multi-walled carbon nanotubes (MWCNTs) and graphene oxide nanosheets (GONS) (oxidized and reduced) were employed for covalent linkage to mono- and binuclear phthalocyanines as conjugates. Transmission electron microscopy was used to characterize ZnO NPs, MWCNTs and GONS alone and when linked to lanthanide Pcs. Lanthanide Pcs alone and when linked to ZnO NPs, MWCNTs and GONS where embedded in polymers such as poly (methyl methacrylate) (PMMA), poly (bisphenol A carbonate) (PBC) and poly (acrylic acid) (PAA) for thin film preparation. The thickness of the thin films was determined by utilization of the knife edge attachment of the A Bruker D8 Discover X-ray diffraction (XRD). Optical limiting properties of lanthanide Pcs alone and as conjugates in solution and when incorporated into polymers were determined by employing a Z-scan technique. It emerged that low symmetry lanthanide Pcs (19, 20 and 21), the blue forms of bis(phthalocyanines) (only in solution; 24 and 28) as well as tris(phthalocyanines) (30 and 31) exhibit low limiting threshold (Ilim) values in solution and thin films (particularly PBC and PAA). The low limiting threshold values make these lanthanide Pcs reliable optical limiters.
- Full Text:
- Date Issued: 2017
Psychological well-being of institutionalised and non-institutionalised isiXhosa and English ethnic speaking elderly south African residing within the Buffalo City area
- Authors: Ntozini, Anathi
- Date: 2017
- Subjects: Self-actualization (Psychology) in old age Older people -- Institutional care -- Psychological aspects
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: http://hdl.handle.net/10353/6368 , vital:29593
- Description: Background: International research has clearly indicated that the world’s population is ageing: almost all countries in the world are experiencing a significant growth in the proportion of older persons in their population. This is also true for developing countries such as South Africa that are beginning to show signs and symptoms of an ageing population. Among Southern African Development Communities (SADC), South Africa has the highest number of ‘senior citizens’. Population reports indicate that the population of old people rose from paltry 2.8 million in 1996 to more than 4 million in 2011 and this is expected to skyrocket to seven million by 2030. In spite of the increasing number of senior citizens in socio-structural landscapes in South Africa, there is still lack of adequate, workable and effective policy frameworks for the wellbeing of the elderly. There is also paucity of psychological data of the elderly, especially along racial divides to determine whether the after-effects of apartheid still hold sway or not in post-apartheid South Africa. This study was conceived to investigate the psychological well-being of the elderly in Buffalo City, Eastern Cape, South Africa between two racial-ethnic elderly groups. The specific objectives of the study were to explore the relationship between the socio-demographic characteristics and psychological well-being of the black (Xhosa) and white (English) elderly in Buffalo City, South Africa and second, to validate the relationship between psychological well-being and physical activity, loneliness, spirituality/religiosity as well as ageism among the sampled population. The set-point theory, selective optimisation compensation theory (SOCT) as well as the continuity theory were employed to guide the conduct of the study. Method: Psychological measuring instruments were deployed to collect data for the study from a total of 301 elderly respondents in retirement and private individual homes (191 isiXhosa and 110 English speaking elderly). Both simple random sampling (SRS) and purposive sampling procedures were used to select the respondents. The measuring instruments included the Ryff Scales of Psychological Well-being (RSPWB), Physical Activity Scale for the Elderly (PASE), Assessment of Spiritual and Religious Sentiments Scale (ASPIRES), University of California at Los Angeles (UCLA) Loneliness Scale, the Palmore Ageism Survey scale and a biographical questionnaire. Data was analysed using MANOVA, One-way variance analysis and regression coefficient. The racial differences logically influenced the selection of the respondents for the study. Results: The study revealed a significant statistical relationship between physical activity (PA) and psychological well-being of the elderly, regardless of the sociodemographic variables. PA showed a significant relationship with psychological wellbeing of the elderly. The study also discovered that loneliness correlates significantly with all four of the psychological well-being scales. It shows that the higher the levels of loneliness experienced by the elderly, socio-demographic variables controlled, the lower the levels of psychological well-being in terms of autonomy, environmental mastery, purpose in life, and self-acceptance. However, with the exception of the relationship between loneliness and purpose in life, ethnic affiliation moderates autonomy, environmental mastery and self-acceptance. English elderly constantly experienced higher levels of autonomy than the isiXhosa elderly do with an increase in loneliness. The study also found a positive relationship between ageism and psychological well- being. However, with low levels of ageism, the English elderly, in comparison with the isiXhosa elderly, is likely to show higher levels of autonomy. In addition, a significant statistical relationship between ageism and environmental mastery and purpose in life was found among the isiXhosa elderly. Although, with an increase in ageism, there is a slight increase in autonomy in both groups, the English elderly throughout showed higher levels of autonomy than the isiXhosa elderly showed. The study found a positive relationship between religiosity/spirituality and psychological well-being of the elderly. However, race could moderate the relationship between prayer fulfillment and psychological well-being at all four levels (autonomy, environmental mastery, purpose in life, and self-acceptance). With an increase in prayer fulfillment, the autonomy of the English elderly increases fairly quickly, while the autonomy of the isiXhosa elderly decreases slightly. Comparatively, the study found that isiXhosa elderly reported lower levels of psychological well-being than the English elderly. Conclusion/Recommendation: The study concludes that there is the need to develop a solid national data bases on needs and use of services, and process of ageing in order to access research data to assist planning, dissemination, delivery and evaluation of effective service delivery for the elderly population in South Africa, especially along racial divides.
- Full Text:
- Date Issued: 2017
- Authors: Ntozini, Anathi
- Date: 2017
- Subjects: Self-actualization (Psychology) in old age Older people -- Institutional care -- Psychological aspects
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: http://hdl.handle.net/10353/6368 , vital:29593
- Description: Background: International research has clearly indicated that the world’s population is ageing: almost all countries in the world are experiencing a significant growth in the proportion of older persons in their population. This is also true for developing countries such as South Africa that are beginning to show signs and symptoms of an ageing population. Among Southern African Development Communities (SADC), South Africa has the highest number of ‘senior citizens’. Population reports indicate that the population of old people rose from paltry 2.8 million in 1996 to more than 4 million in 2011 and this is expected to skyrocket to seven million by 2030. In spite of the increasing number of senior citizens in socio-structural landscapes in South Africa, there is still lack of adequate, workable and effective policy frameworks for the wellbeing of the elderly. There is also paucity of psychological data of the elderly, especially along racial divides to determine whether the after-effects of apartheid still hold sway or not in post-apartheid South Africa. This study was conceived to investigate the psychological well-being of the elderly in Buffalo City, Eastern Cape, South Africa between two racial-ethnic elderly groups. The specific objectives of the study were to explore the relationship between the socio-demographic characteristics and psychological well-being of the black (Xhosa) and white (English) elderly in Buffalo City, South Africa and second, to validate the relationship between psychological well-being and physical activity, loneliness, spirituality/religiosity as well as ageism among the sampled population. The set-point theory, selective optimisation compensation theory (SOCT) as well as the continuity theory were employed to guide the conduct of the study. Method: Psychological measuring instruments were deployed to collect data for the study from a total of 301 elderly respondents in retirement and private individual homes (191 isiXhosa and 110 English speaking elderly). Both simple random sampling (SRS) and purposive sampling procedures were used to select the respondents. The measuring instruments included the Ryff Scales of Psychological Well-being (RSPWB), Physical Activity Scale for the Elderly (PASE), Assessment of Spiritual and Religious Sentiments Scale (ASPIRES), University of California at Los Angeles (UCLA) Loneliness Scale, the Palmore Ageism Survey scale and a biographical questionnaire. Data was analysed using MANOVA, One-way variance analysis and regression coefficient. The racial differences logically influenced the selection of the respondents for the study. Results: The study revealed a significant statistical relationship between physical activity (PA) and psychological well-being of the elderly, regardless of the sociodemographic variables. PA showed a significant relationship with psychological wellbeing of the elderly. The study also discovered that loneliness correlates significantly with all four of the psychological well-being scales. It shows that the higher the levels of loneliness experienced by the elderly, socio-demographic variables controlled, the lower the levels of psychological well-being in terms of autonomy, environmental mastery, purpose in life, and self-acceptance. However, with the exception of the relationship between loneliness and purpose in life, ethnic affiliation moderates autonomy, environmental mastery and self-acceptance. English elderly constantly experienced higher levels of autonomy than the isiXhosa elderly do with an increase in loneliness. The study also found a positive relationship between ageism and psychological well- being. However, with low levels of ageism, the English elderly, in comparison with the isiXhosa elderly, is likely to show higher levels of autonomy. In addition, a significant statistical relationship between ageism and environmental mastery and purpose in life was found among the isiXhosa elderly. Although, with an increase in ageism, there is a slight increase in autonomy in both groups, the English elderly throughout showed higher levels of autonomy than the isiXhosa elderly showed. The study found a positive relationship between religiosity/spirituality and psychological well-being of the elderly. However, race could moderate the relationship between prayer fulfillment and psychological well-being at all four levels (autonomy, environmental mastery, purpose in life, and self-acceptance). With an increase in prayer fulfillment, the autonomy of the English elderly increases fairly quickly, while the autonomy of the isiXhosa elderly decreases slightly. Comparatively, the study found that isiXhosa elderly reported lower levels of psychological well-being than the English elderly. Conclusion/Recommendation: The study concludes that there is the need to develop a solid national data bases on needs and use of services, and process of ageing in order to access research data to assist planning, dissemination, delivery and evaluation of effective service delivery for the elderly population in South Africa, especially along racial divides.
- Full Text:
- Date Issued: 2017
Phthalocyanine-nanoparticle conjugates for photodynamic therapy of cancer and phototransformation of organic pollutants
- Authors: Khoza, Phindile Brenda
- Date: 2015
- Subjects: Phthalocyanines , Nanoparticles , Photochemotherapy , Cancer -- Chemotherapy , Zinc oxide , Photocatalysis
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:4538 , http://hdl.handle.net/10962/d1017918
- Description: The synthesis and extensive spectroscopical characterization of novel phthalocyanines are reported. The new compounds were characterized by elemental analysis, FT-IR, ¹HNMR, mass spectrometry and UV–Vis spectroscopy. The new phthalocyanines showed remarkable photophysicochemical behaviour. The novel phthalocyanines were then conjugated to nanoparticles, silver and ZnO. The coupling of the novel Pcs to nanoparticles was through covalent bonding and ligand exchange. These conjugates were supported onto electrospun polystyrene fibers and chitosan microbeads for use as photocatalysts. The efficiency of the immobilized Pcs and Pc-nanoparticles was assessed by the phototrasfromation of organic pollutants, methyl orange and Rhodamine 6G as model dyes. Upon conjugating phthalocyanines to nanoparticles, there was a great increase in the rate of photodegradation of the model dyes. The photodynamic activity of the novel phthalocyanines upon conjugating to nanoparticles and selected targeting agents is also reported. The targeting agents employed in this study are folic acid and polylysine. Conjugating the phthalocyanines to folic acid or polylysine improved the solubility of the phthalocyanines in aqueous media. The potency of the conjugates was investigated on breast (MCF-7), prostate and melanoma cancer cell lines. The phthalocyanines showed no toxicity in the absence of light. However, upon illumination, a concentration dependent cellular decrease was observed.
- Full Text:
- Date Issued: 2015
- Authors: Khoza, Phindile Brenda
- Date: 2015
- Subjects: Phthalocyanines , Nanoparticles , Photochemotherapy , Cancer -- Chemotherapy , Zinc oxide , Photocatalysis
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:4538 , http://hdl.handle.net/10962/d1017918
- Description: The synthesis and extensive spectroscopical characterization of novel phthalocyanines are reported. The new compounds were characterized by elemental analysis, FT-IR, ¹HNMR, mass spectrometry and UV–Vis spectroscopy. The new phthalocyanines showed remarkable photophysicochemical behaviour. The novel phthalocyanines were then conjugated to nanoparticles, silver and ZnO. The coupling of the novel Pcs to nanoparticles was through covalent bonding and ligand exchange. These conjugates were supported onto electrospun polystyrene fibers and chitosan microbeads for use as photocatalysts. The efficiency of the immobilized Pcs and Pc-nanoparticles was assessed by the phototrasfromation of organic pollutants, methyl orange and Rhodamine 6G as model dyes. Upon conjugating phthalocyanines to nanoparticles, there was a great increase in the rate of photodegradation of the model dyes. The photodynamic activity of the novel phthalocyanines upon conjugating to nanoparticles and selected targeting agents is also reported. The targeting agents employed in this study are folic acid and polylysine. Conjugating the phthalocyanines to folic acid or polylysine improved the solubility of the phthalocyanines in aqueous media. The potency of the conjugates was investigated on breast (MCF-7), prostate and melanoma cancer cell lines. The phthalocyanines showed no toxicity in the absence of light. However, upon illumination, a concentration dependent cellular decrease was observed.
- Full Text:
- Date Issued: 2015
Development of conservation methods for gunnera perpensa l.: an overexploited medicinal plant in the Eastern Cape, South Africa
- Authors: Chigor, Chinyere Blessing
- Date: 2014
- Subjects: Gunnera -- South Africa -- Eastern Cape , Medicinal plants -- South Africa -- Eastern Cape , Traditional medicine -- South Africa -- Eastern Cape , Medical anthropology -- South Africa -- Eastern Cape , Medical policy -- South Africa -- Eastern Cape
- Language: English
- Type: Thesis , Doctoral , PhD (Botany)
- Identifier: vital:11311 , http://hdl.handle.net/10353/d1019832 , Gunnera -- South Africa -- Eastern Cape , Medicinal plants -- South Africa -- Eastern Cape , Traditional medicine -- South Africa -- Eastern Cape , Medical anthropology -- South Africa -- Eastern Cape , Medical policy -- South Africa -- Eastern Cape
- Description: South Africa, many plants which are used in traditional medicines are collected from wild populations. The high demand for trade and use of these medicinal plants place an enormous pressure on their natural populations, especially because they are indiscriminately harvested. The most affected of these plant species are those harvested from their underground parts, among which is Gunnera perpensa L. Gunnera perpensa is of considerable ethnobotanical interest in traditional medicine because of its wide usage. The rhizomes are widely used and indiscriminately collected in large quantities from the wild to meet the ever increasing demand in traditional medicine markets. As a result, this valuable medicinal plant species is being endangered. According to the Red List of South African Plants, the conservation status of G. perpensa has been listed as ‘declining’. The ethnobotanical survey conducted as part of this research confirms the plant species as threatened. It is, therefore, important to develop propagation and conservation strategies for this medicinal plant. Clonal propagation of G. perpensa was conducted using varying lengths of the rhizome (1, 2, 3, 4 and 5 cm) segments as propagules. While regeneration was possible with all the rhizome lengths, most of the growth parameters were significantly higher in the 5 cm rhizomes than the other rhizome segments. The appropriate planting depth for the rhizomes was also determined and 4 or 5 cm planting depths were found appropriate. No significant difference was observed in the growth parameters amongst the planting depths; nevertheless, 4 cm depth gave higher growth and yield. The results of this study show that regenerating G. perpensa.
- Full Text:
- Date Issued: 2014
- Authors: Chigor, Chinyere Blessing
- Date: 2014
- Subjects: Gunnera -- South Africa -- Eastern Cape , Medicinal plants -- South Africa -- Eastern Cape , Traditional medicine -- South Africa -- Eastern Cape , Medical anthropology -- South Africa -- Eastern Cape , Medical policy -- South Africa -- Eastern Cape
- Language: English
- Type: Thesis , Doctoral , PhD (Botany)
- Identifier: vital:11311 , http://hdl.handle.net/10353/d1019832 , Gunnera -- South Africa -- Eastern Cape , Medicinal plants -- South Africa -- Eastern Cape , Traditional medicine -- South Africa -- Eastern Cape , Medical anthropology -- South Africa -- Eastern Cape , Medical policy -- South Africa -- Eastern Cape
- Description: South Africa, many plants which are used in traditional medicines are collected from wild populations. The high demand for trade and use of these medicinal plants place an enormous pressure on their natural populations, especially because they are indiscriminately harvested. The most affected of these plant species are those harvested from their underground parts, among which is Gunnera perpensa L. Gunnera perpensa is of considerable ethnobotanical interest in traditional medicine because of its wide usage. The rhizomes are widely used and indiscriminately collected in large quantities from the wild to meet the ever increasing demand in traditional medicine markets. As a result, this valuable medicinal plant species is being endangered. According to the Red List of South African Plants, the conservation status of G. perpensa has been listed as ‘declining’. The ethnobotanical survey conducted as part of this research confirms the plant species as threatened. It is, therefore, important to develop propagation and conservation strategies for this medicinal plant. Clonal propagation of G. perpensa was conducted using varying lengths of the rhizome (1, 2, 3, 4 and 5 cm) segments as propagules. While regeneration was possible with all the rhizome lengths, most of the growth parameters were significantly higher in the 5 cm rhizomes than the other rhizome segments. The appropriate planting depth for the rhizomes was also determined and 4 or 5 cm planting depths were found appropriate. No significant difference was observed in the growth parameters amongst the planting depths; nevertheless, 4 cm depth gave higher growth and yield. The results of this study show that regenerating G. perpensa.
- Full Text:
- Date Issued: 2014
Application of bidentate N,N'-donor extractants in the hydrometallurgical separation of base metals from an acidic sulfate medium
- Authors: Okewole, Adeleye Ishola
- Date: 2013
- Subjects: Hydrometallurgy Sulfates Nanofibers Electrospinning Sorbents Extraction (Chemistry) Solvent extraction Stereochemistry
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:4281 , http://hdl.handle.net/10962/d1002610
- Description: Bidentate imidazole-based extractants, 1-octylimidazole-2-aldoxime (OIMOX) and 1-octyl-2-(2′-pyridyl)imidazole (OPIM), along with dinonylnaphthalene sulfonic acid (DNNSA) as a synergist, were investigated as potential selective extractants for Cu²⁺and Ni²⁺ respectively from base metals in a solvent extraction system. The study was extended to evaluate the sorption and separation of Ni²⁺ from other base metals in a solid-solution system using microspherical Merrifield resins and nanofibers functionalized with 2,2′-pyridylimidazole. Copper was effectively separated with OIMOX and DNNSA as extractants from nickel with ΔpH½ ≈1.05 and the extraction order of Cu²⁺ > Ni²⁺ > Zn²⁺ > Cd²⁺> Co²⁺ was achieved as a function of pH. At pH 1.65 the extracted copper, from a synthetic mixture of the base metals reached 90.13(±0.90)%, and through a two-step extraction process 98.22(±0.29)% copper was recovered with negligible nickel and cobalt impurities. Stripping of the copper from the loaded organic phase using TraceSelect sulphuric acid at pH 0.35 yielded 96.60(±0.44)% of the loaded quantity after the second stage of stripping. The separation of Ni²⁺ from the borderline and hard acids; Co²⁺, Cu²⁺, Zn²⁺, Fe2²⁺, Fe²⁺, Mn²⁺, Mg2²⁺ and Ca²⁺ at a pH range of 0.5-3.5 with OPIM and DNNSA was acvieved to the tune of a ΔpH½≈ 1.6 with respect to cobalt from a sulfate and sulfate/chloride media. A three-stage counter-current extraction of Ni²⁺, at the optimized pH of 1.89, from a synthetic mixture of Ni²⁺, Co²⁺ and Cu²⁺, yielded 99.01(±1.79)%. The total co-extracted Cu²⁺ was 48.72(±0.24)% of the original quantity in the mixture, and it was 19.85(±0.28%) for Co²⁺. The co-extracted Cu²⁺ was scrubbed off from the loaded organic phase at pH≈8.5 by using an ammonium buffer, while co-extracted Co²⁺ was selectively and quantitatively stripped with H₂SO₄ at pH 1.64. The total recovery of Ni²⁺ by stripping at pH 0.32 was 94.05(±1.70)%. In the solid-liquid system, Ni²⁺ was separated from Co²⁺, Cu²⁺, and Fe²⁺ with the microspherical resins funtionalised with 2,2′-pyridylimidazole by a separation factor (β) in the range 22-45. Electrospun nanofibers as sorbents yielded high sorption capacity in the range of 0.97 - 1.45 mmol.g⁻¹ for the same metals ions. Thus, 1-octylimidazole-2-aldoxime (OIMOX), and1-octyl-2-(2′-pyridyl)imidazole (OPIM) can be effectively utilized alongside DNNSA as a co-extractant in the separation of Cu²⁺ and Ni²⁺ respectively from base metals in acidic sulfate medium in a solvent extraction process, and the latter as a selective ligand in the solid-liquid separation of Ni²⁺ from Co²⁺, Cu²⁺, and Fe²⁺.
- Full Text:
- Date Issued: 2013
- Authors: Okewole, Adeleye Ishola
- Date: 2013
- Subjects: Hydrometallurgy Sulfates Nanofibers Electrospinning Sorbents Extraction (Chemistry) Solvent extraction Stereochemistry
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:4281 , http://hdl.handle.net/10962/d1002610
- Description: Bidentate imidazole-based extractants, 1-octylimidazole-2-aldoxime (OIMOX) and 1-octyl-2-(2′-pyridyl)imidazole (OPIM), along with dinonylnaphthalene sulfonic acid (DNNSA) as a synergist, were investigated as potential selective extractants for Cu²⁺and Ni²⁺ respectively from base metals in a solvent extraction system. The study was extended to evaluate the sorption and separation of Ni²⁺ from other base metals in a solid-solution system using microspherical Merrifield resins and nanofibers functionalized with 2,2′-pyridylimidazole. Copper was effectively separated with OIMOX and DNNSA as extractants from nickel with ΔpH½ ≈1.05 and the extraction order of Cu²⁺ > Ni²⁺ > Zn²⁺ > Cd²⁺> Co²⁺ was achieved as a function of pH. At pH 1.65 the extracted copper, from a synthetic mixture of the base metals reached 90.13(±0.90)%, and through a two-step extraction process 98.22(±0.29)% copper was recovered with negligible nickel and cobalt impurities. Stripping of the copper from the loaded organic phase using TraceSelect sulphuric acid at pH 0.35 yielded 96.60(±0.44)% of the loaded quantity after the second stage of stripping. The separation of Ni²⁺ from the borderline and hard acids; Co²⁺, Cu²⁺, Zn²⁺, Fe2²⁺, Fe²⁺, Mn²⁺, Mg2²⁺ and Ca²⁺ at a pH range of 0.5-3.5 with OPIM and DNNSA was acvieved to the tune of a ΔpH½≈ 1.6 with respect to cobalt from a sulfate and sulfate/chloride media. A three-stage counter-current extraction of Ni²⁺, at the optimized pH of 1.89, from a synthetic mixture of Ni²⁺, Co²⁺ and Cu²⁺, yielded 99.01(±1.79)%. The total co-extracted Cu²⁺ was 48.72(±0.24)% of the original quantity in the mixture, and it was 19.85(±0.28%) for Co²⁺. The co-extracted Cu²⁺ was scrubbed off from the loaded organic phase at pH≈8.5 by using an ammonium buffer, while co-extracted Co²⁺ was selectively and quantitatively stripped with H₂SO₄ at pH 1.64. The total recovery of Ni²⁺ by stripping at pH 0.32 was 94.05(±1.70)%. In the solid-liquid system, Ni²⁺ was separated from Co²⁺, Cu²⁺, and Fe²⁺ with the microspherical resins funtionalised with 2,2′-pyridylimidazole by a separation factor (β) in the range 22-45. Electrospun nanofibers as sorbents yielded high sorption capacity in the range of 0.97 - 1.45 mmol.g⁻¹ for the same metals ions. Thus, 1-octylimidazole-2-aldoxime (OIMOX), and1-octyl-2-(2′-pyridyl)imidazole (OPIM) can be effectively utilized alongside DNNSA as a co-extractant in the separation of Cu²⁺ and Ni²⁺ respectively from base metals in acidic sulfate medium in a solvent extraction process, and the latter as a selective ligand in the solid-liquid separation of Ni²⁺ from Co²⁺, Cu²⁺, and Fe²⁺.
- Full Text:
- Date Issued: 2013
Assessing the impact of school governance in the Limpopo Department of Education with specific reference to Mankweng and Polokwane circuits
- Authors: Mothapo, Sentshuhleng Jacob
- Date: 2011
- Subjects: School management and organization -- South Africa -- Limpopo , Leadership -- South Africa -- Limpopo , Responsibility -- South Africa -- Limpopo , Teacher effectiveness -- South Africa -- Limpopo , School boards -- South Africa -- Limpopo
- Language: English
- Type: Thesis , Doctoral , PhD (in Public Administration)
- Identifier: vital:11663 , http://hdl.handle.net/10353/d1007096 , School management and organization -- South Africa -- Limpopo , Leadership -- South Africa -- Limpopo , Responsibility -- South Africa -- Limpopo , Teacher effectiveness -- South Africa -- Limpopo , School boards -- South Africa -- Limpopo
- Description: Education has been identified as a priority area by the South African government, in particular by the African National Congress as the ruling party. To this end, huge amounts of money are being spent on education as a service that has been approved by the legislators. Rules and regulations have been promulgated, and among others, the South African Schools Act, Act No. 84 of 1996, has been enacted. Rich research has also been funded with the sole intention of providing quality education to the people. Education of unacceptably poor quality has, however, been the result, as postulated by Peterson and Hassel (1998:55). The above are attested to by the findings that the political tensions emanating from the conduct of the South African Democratic Teachers’ Union and the Professional Educators’ Union, leading to class disruptions and general instability, erode the ethos of accountability on the part of educators and therefore impact negatively on service delivery. Furthermore, the Limpopo Department of Education is not immune to the challenges ranging from the elements of corrupt activities that often surface, teacher attrition which in the main is caused by lack of discipline. Winkler, Modise and Dawber (1998) indicate that teaching has never been easy, and many teachers are leaving their jobs because of the many problems with children in classrooms. Some of the problems cited are children who do not want to learn and learning that is becoming too difficult for the students because they do not want to listen. This study adopted sequential mixed methods namely, quantitative and qualitative research methods which are viewed as complementary rather than opposing approaches. Information was amassed from the subjects through interviews, observation, documentary survey and observation and the information has since been triangulated to validate the facts. All the methodologies employed proved to be useful in this study. The study sought to test the hypothesis “Good governance is informed by strong accountability and future-oriented organisation, continuously steering it towards its mission and vision, and thereby ensuring that the day-to-day management and administration are always linked with the organisation’s values and goals and thus eventually bringing about effectual and accelerated service delivery” to the South African populace without compromise. After empirically testing the hypothesis, showing mixed reaction informed by the findings of the study, five recommendations were made, based on the conclusions arrived at.
- Full Text:
- Date Issued: 2011
- Authors: Mothapo, Sentshuhleng Jacob
- Date: 2011
- Subjects: School management and organization -- South Africa -- Limpopo , Leadership -- South Africa -- Limpopo , Responsibility -- South Africa -- Limpopo , Teacher effectiveness -- South Africa -- Limpopo , School boards -- South Africa -- Limpopo
- Language: English
- Type: Thesis , Doctoral , PhD (in Public Administration)
- Identifier: vital:11663 , http://hdl.handle.net/10353/d1007096 , School management and organization -- South Africa -- Limpopo , Leadership -- South Africa -- Limpopo , Responsibility -- South Africa -- Limpopo , Teacher effectiveness -- South Africa -- Limpopo , School boards -- South Africa -- Limpopo
- Description: Education has been identified as a priority area by the South African government, in particular by the African National Congress as the ruling party. To this end, huge amounts of money are being spent on education as a service that has been approved by the legislators. Rules and regulations have been promulgated, and among others, the South African Schools Act, Act No. 84 of 1996, has been enacted. Rich research has also been funded with the sole intention of providing quality education to the people. Education of unacceptably poor quality has, however, been the result, as postulated by Peterson and Hassel (1998:55). The above are attested to by the findings that the political tensions emanating from the conduct of the South African Democratic Teachers’ Union and the Professional Educators’ Union, leading to class disruptions and general instability, erode the ethos of accountability on the part of educators and therefore impact negatively on service delivery. Furthermore, the Limpopo Department of Education is not immune to the challenges ranging from the elements of corrupt activities that often surface, teacher attrition which in the main is caused by lack of discipline. Winkler, Modise and Dawber (1998) indicate that teaching has never been easy, and many teachers are leaving their jobs because of the many problems with children in classrooms. Some of the problems cited are children who do not want to learn and learning that is becoming too difficult for the students because they do not want to listen. This study adopted sequential mixed methods namely, quantitative and qualitative research methods which are viewed as complementary rather than opposing approaches. Information was amassed from the subjects through interviews, observation, documentary survey and observation and the information has since been triangulated to validate the facts. All the methodologies employed proved to be useful in this study. The study sought to test the hypothesis “Good governance is informed by strong accountability and future-oriented organisation, continuously steering it towards its mission and vision, and thereby ensuring that the day-to-day management and administration are always linked with the organisation’s values and goals and thus eventually bringing about effectual and accelerated service delivery” to the South African populace without compromise. After empirically testing the hypothesis, showing mixed reaction informed by the findings of the study, five recommendations were made, based on the conclusions arrived at.
- Full Text:
- Date Issued: 2011
A networking approach to sharing music studio resources
- Authors: Foss, Richard John
- Date: 1996
- Subjects: MIDI (Standard) Computer sound processing Sound -- Recording and reproducing -- Digital techniques
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:4659 , http://hdl.handle.net/10962/d1006660
- Description: This thesis investigates the extent to which networking technology can be used to provide remote workstation access to a pool of shared music studio resources. A pilot system is described in which MIDI messages, studio control data, and audio signals flow between the workstations and a studio server. A booking and timing facility avoids contention and allows for accurate reports of studio usage. The operation of the system has been evaluated in terms of its ability to satislY three fundamental goals, namely the remote, shared and centralized access to studio resources. Three essential network configurations have been identified, incorporating a mix of star and bus topologies, and their relative potential for satisfYing the fundamental goals has been highlighted.
- Full Text:
- Date Issued: 1996
- Authors: Foss, Richard John
- Date: 1996
- Subjects: MIDI (Standard) Computer sound processing Sound -- Recording and reproducing -- Digital techniques
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:4659 , http://hdl.handle.net/10962/d1006660
- Description: This thesis investigates the extent to which networking technology can be used to provide remote workstation access to a pool of shared music studio resources. A pilot system is described in which MIDI messages, studio control data, and audio signals flow between the workstations and a studio server. A booking and timing facility avoids contention and allows for accurate reports of studio usage. The operation of the system has been evaluated in terms of its ability to satislY three fundamental goals, namely the remote, shared and centralized access to studio resources. Three essential network configurations have been identified, incorporating a mix of star and bus topologies, and their relative potential for satisfYing the fundamental goals has been highlighted.
- Full Text:
- Date Issued: 1996
The South African anaphora: the development of the anaphora of the South African Eucharistic rite
- Authors: Hinchliff, Peter Bingham
- Date: 1958
- Subjects: Church of the Province of South Africa. Book of common prayer -- History -- Sources Eucharistic prayers Eucharistic prayers -- Anglican Communion Anglican Communion -- Liturgy -- History -- Sources Anglican Communion -- South Africa -- Liturgy -- History -- Sources.
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:1260 , http://hdl.handle.net/10962/d1012293
- Description: The Prayer Book of the Church of England reached South Africa as a part of the establishment of the British Administration at the Cape. In its new environment it obviously required some revision. The Book of 1662 reflected the political and social conditions of its time. lt was designed for a Church not immediately concerned with missionary work amongst heathen peoples but directly established under the Crown. The circumstances of a Church in the colonies, particularly when the colonies became self-governing, required some modernisation of language, some omission and adaptation of old prayers and some addition of new ones. Yet the Church appears to have been wary of attempting anything more than this, and it was especially reluctant to make any revision which might imply a doctrinal change. The consecration prayer in the liturgy -'our incomparable liturgy' - was particularly sacrosanct by virtue of long use and the accretion of sentimental associations. Revision of this part of the book would naturally be slow and hesitant and this is the revision with which we are concerned - the most interesting and important part of the history of the South African Prayer Book. Chapter 1, p. 6.
- Full Text:
- Date Issued: 1958
- Authors: Hinchliff, Peter Bingham
- Date: 1958
- Subjects: Church of the Province of South Africa. Book of common prayer -- History -- Sources Eucharistic prayers Eucharistic prayers -- Anglican Communion Anglican Communion -- Liturgy -- History -- Sources Anglican Communion -- South Africa -- Liturgy -- History -- Sources.
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:1260 , http://hdl.handle.net/10962/d1012293
- Description: The Prayer Book of the Church of England reached South Africa as a part of the establishment of the British Administration at the Cape. In its new environment it obviously required some revision. The Book of 1662 reflected the political and social conditions of its time. lt was designed for a Church not immediately concerned with missionary work amongst heathen peoples but directly established under the Crown. The circumstances of a Church in the colonies, particularly when the colonies became self-governing, required some modernisation of language, some omission and adaptation of old prayers and some addition of new ones. Yet the Church appears to have been wary of attempting anything more than this, and it was especially reluctant to make any revision which might imply a doctrinal change. The consecration prayer in the liturgy -'our incomparable liturgy' - was particularly sacrosanct by virtue of long use and the accretion of sentimental associations. Revision of this part of the book would naturally be slow and hesitant and this is the revision with which we are concerned - the most interesting and important part of the history of the South African Prayer Book. Chapter 1, p. 6.
- Full Text:
- Date Issued: 1958
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