3. Electronic Theses and Dissertations (ETDs) - All submissions
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Item Effects of hydroethanolic Moringa oleifera lam: Seed extract on high-fructose diet fed growing Sprague-Dawley rats(2020) Mapfumo, MasilineFructose consumption contributes to the development of non-alcoholic fatty liver disease (NAFLD) and metabolic syndrome (MetS). The anti-obesogenic and hepatoprotective properties of crude Moringa oleifera seed extract make it a potential prophylactic ethnomedicine against diet-induced NAFLD and MetS. This study interrogated the potential of crude hydroethanolic M. oleifera seed extract to protect against high-fructose diet-induced metabolic dysfunction. Eighty-eight 21-day old female and male Sprague-Dawley rat pups were randomly allocated to and administered one of the following five treatment regimens (8 female rats and 9-10 male rats per treatment) daily for twelve weeks: group I - plain drinking water (PW) + plain gelatine cube (PC), group II - 20% (w/v) fructose solution (FS) + PC, group III - FS + 100 mg/kg body mass fenofibrate in gelatine cube (FN), group IV - FS + low dose (50 mg/kg body mass) of M. oleifera in gelatine cube (LMol) and group V - FS + high dose (500 mg/kg body mass) of M. oleifera in gelatine cube (HMol). The rats in each treatment regimen had ad libitum access to a standard rat chow and were weighed twice weekly. At the end of the 12- week trial, the rats were subjected to an oral glucose tolerance test and then euthanised 48 hours later. Blood was collected via cardiac puncture and plasma was harvested. Plasma triglyceride, cholesterol and insulin concentration, HOMA-IR, and surrogate biomarkers of liver function were determined. The livers and visceral fat pads were dissected out, weighed and preserved for liver lipid content and histology analysis. The consumption of a high-fructose diet increased (p<0.05) liver lipid content and caused steatosis and hypertriglyceridemia in female and male rats. Crude hydroethanolic M. oleifera seed extract and fenofibrate prevented the high-fructose diet-induced liver lipid accretion and steatosis in female and male rats. High-fructose diet increased (p<0.05) visceral fat pad mass, plasma insulin concentration and HOMA-IR in female rats only. The crude hydroethanolic M. oleifera seed extract prevented the high-fructose diet-induced hyperinsulinemia and insulin resistance in female rats but failed to prevent the visceral adiposity. Crude hydroethanolic M. oleifera seed extract did not compromise liver function. The crude hydroethanolic M. oleifera seed extract can potentially be exploited as prophylaxis against diet-induced fatty liver disease and MetS without causing liver toxicity in childrenItem Synthesis of magnetic sorbents modifie with moringa oleifera extracts for the removals of environmental orgamnic pollutants(2018) Kgatitsoe, Maureen MaletsatsiModern developments on nanoparticles (NPs) has led to new innovation in nanoparticles that can be used for the treatment of polluted water. Magnetic NPs are of great interest because of their unique properties and promising applications. Their stability is essential to prevent them from agglomeration, hence, modification with a specific coating layer can assist in the selectivity function and stability of the magnetic NPs. In this work, a magnetic organic nano-adsorbent was synthesized and investigated for the application in the extraction of nitroaromatic explosive compounds from aqueous solutions. The approach was to find a possible synergy between the adsorptive properties of Moringa oleifera and the high surface area of the NPs. The magnetic NPs were utilized for their ferromagnetic properties which assist in the extraction procedure. M. oleifera was used as a natural coating agent to functionalize the magnetic NPs and also to provide stability. There are numerous chemical procedures to synthesize magnetite and one of the simplest and convenient procedures, co-precipitation, was used in this study. Magnetite can be easily oxidized under ambient conditions, hence, in order to prevent oxidation, M. oleifera extracts were used as a coating agent. The synthesized uncoated magnetite NPs and M. oleifera coated magnetite NPs were characterized by powder X-ray diffraction (PXRD), Fourier transform infrared (FTIR), Brunauer, Emmett and Teller (BET) and thermogravimetric analysis (TGA). The M. oleifera leaf extract was obtained using pressurized hot water extraction (PHWE) at 80°C and the seed extract was purchased as a pure oil. Both the M. oleifera leaf and seed extracts were characterized by FTIR and gas chromatography–mass spectrometry (GC-MS) for possible organic compounds assisting in the stability of the magnetite. From the BET results of the coated magnetic NPs at different times, it was observed that with increasing coating time, the surface area decreased while the pore size increased. To optimize the extraction of nitroaromatic explosive compounds (NAECs), the parameters that were investigated were sample pH, contact time, mass of adsorbent and initial concentration. The optimum value for pH of the sample was found at pH8 and for the contact time an optimum of 120 min was found. The mass of M. oleifera coated magnetic NPs for the maximum removal of explosives were found to be 100 mg. The adsorption capacity of the NAECs was obtained in the range of 0.45 and 0.76 mg g-1 at optimum conditions. During kinetic studies it was observed that the pseudo second order model explained the extent of the adsorption mechanism. It was observed that the Langmuir model was favourable as compared to the Freundlich model. The order of selectivity for the NAECs studied was observed as follows: 2-NT ≈ 3-NT > 4NT > NB > 2,6-DNT > 1,3-DNB. The limit of detection (LOD) found was 0.37 – 4.47 and 0.45 – 5.66 ng.mL-1 for extraction using magnetic NPs coated with M. oleifera leaf and seed extract, respectively. The percentage recovery for the extraction of NAECs at optimum conditions was obtained in the range 14 – 46%.Item Metabolomic exploration of pharmacologically relevant metabolites in Moringa oleifera and Moringa ovalifolia through the use of UPLC-qTOF-MS and multivariate models(2017) Makita, Charlene SampuPlant metabolomics is considered a holistic qualitative and quantitative analysis of primary and secondary metabolites under specific conditions. Metabolomics provides functional information that is important in the biological studies of plants. Moreover, chromatographic techniques in combination with mass spectrometry are presently commonly utilized analytical technologies that are used in metabolomics studies. Moringa oleifera (M. oleifera) is an acclaimed medicinal herb and is considered one of the most superior plants based on its nutritional and medicinal attributes. Signature compounds such as chlorogenic acids and flavonoids found in Moringa plants are considered beneficial as they are responsible for the health properties found in these plants. Out of the 13 species belonging to the Moringaceae family, M. oleifera is the most widely studied. Furthermore, plants are known to produce compounds, such as flavonoids, as a response to biotic stresses (pest resistance) and abiotic stresses (harsh environmental conditions such as drought or cold). Other species belonging to the Moringaceae family such as Moringa ovalifolia (M. ovalifolia), located in the dry desert and semi-desert areas of Namibia, has not been reported much in literature. Moreover, there is very little work done on other classes of compounds that are possibly present in M. ovalifolia. Therefore, the significant correlation between desert plants and their possible increased flavonoid content is of interest in this study and is worth investigating. Moreover, in an effort to compare Moringa species in that regard, a holistic approach to metabolite fingerprinting using UPLC-qTOF-MS was thus employed for the characterization of possible metabolite markers and taxonomical differences in M. ovalifolia and M. oleifera plant species (Paper I). From the results, 17 flavonoid compounds were identified. Interestingly, M. oleifera and M. ovalifolia had a similar aglycone profile, however, they had a different sugar moiety. Rutinoside sugar moieties were only found to be present in M. ovalifolia indicating that it is only capable of attaching the rutinoside sugar moiety to its flavonoid skeleton. M. oleifera, however, is capable of attaching many sugar moieties to its flavonoid skeleton. The outcomes of this research additionally demonstrated for the first time the significance of sugar attachment for taxonomical classification of related species and that the contrasts between the grouped species are likely because of genetic variations as opposed to environmental influences. This study further provided potential chemotaxonomic biomarkers and a classification model was generated to classify and differentiate between closely related Moringa species utilizing multivariate analysis (Paper III). Moreover, chlorogenic acids which are esters formed between derivatives such as cinnamic acid and quinic acid molecules, were identified in M. ovalifolia plants species for the first time (Paper II ). Chlorogenic acids are difficult to identify and differentiate since they are structurally complex. This study demonstrated the effectiveness of an UPLC-ISCID-MS/MS based platform to aid in the profiling of isomers and derivatives of chlorogenic acids present in M. ovalifolia. This approach further showed M. ovalifolia as a valuable source of molecules with therapeutic potential. Based on the classification model generated in Paper II, the biomarkers identified were utilized in order to differentiate between 12 M. oleifera cultivars (Paper III). Three sought after flavonoid compounds, namely, quercetin rutinoside (rutin), kaempferol rutinoside and isorhamnetin rutinoside were identified as potential chemotaxonomic markers amongst the 12 Moringa cultivars. Metabolite distribution patterns of the 12 cultivars were analyzed using a metabolomics approach with the aid of UHPLC-qTOF-MS in combination with multivariate data models such as principal component analysis (PCA), hierarchical clustering analysis (HCA) and box-whiskers plot. According to the results, three main cultivars, namely: TOT4977, CHM and TOT5330 were identified as potential cultivars for pharmacological and nutritional purposes according to the presence and abundance of the three studied rutinoside bearing flavonoid molecules.