Thesis (Ph. D.)--Ohio State University, 2005. / Available online via OhioLINK's ETD Center; full text release delayed at author's request until 2006 May 17.

Thesis (Ph.D.)--Hong Kong University of Science and Technology, 2005. / Includes bibliographical references. Also available in electronic version.

Thesis (M.S.)--University of North Carolina Wilmington, 2007. / Includes bibliographical references (leaves: 108-109)

Thesis (Ph. D.)--Ohio State University, 2007. / Title from first page of PDF file. Includes bibliographical references (p. 185-221).

Thesis (Ph.D.)--University of Nebraska-Lincoln, 2008. / Title from title screen (site viewed Feb. 17, 2009). PDF text: 182 p. : ill. (chiefly col.) ; 5 Mb. UMI publication number: AAT 3328255. Includes bibliographical references. Also available in microfilm and microfiche formats.

Novel non-leaving groups were employed in this dissertation to synthesize platinum complexes which can assist in the understanding or improvement of anticancer action. Emphasis was placed on (NS)-chelate and (NN)-chelate platinum complexes. Bidentate (NS)-donor ligands were used as non-leaving ligands in the synthesis of platinum(II) complexes with iodo, chloro, bromo and oxalato groups as leaving groups. These complexes were synthesized and studied since many questions regarding the interaction of sulfur-donors and platinum still exist. These relate to thermodynamic and kinetic factors and their influence on anticancer action. In this dissertation the properties of novel platinum(II) complexes of a bidentate ligand having an aromatic nitrogen-donor atom in combination with a thioethereal sulfur atom capable of forming a five-membered ring with platinum(II) were studied. The general structure of the (NS)-ligands used was 2-((alkylthio)methyl)pyridine. Alkyl groups used were methyl, ethyl, propyl, benzyl and phenyl. Amine complexes of platinum have been studied extensively in the past. However, attention was given to novel aspects of substituted pyridine and imidazole ligands and their corresponding complexes. Amongst these are 2-(2-methylaminoethyl)pyridine, 1-methyl-2-methylaminoethylimidazole and 1-methyl-2-methylaminobenzylimidazole. The leaving groups included chloro, bromo and oxalato. Mononitroplatinum(IV) complexes were prepared using novel synthetic methods. Selected platinum(II) amine complexes were used as starting materials for this synthesis. Some of these compounds exhibit promising anticancer behaviour. (Trans-(R,R)-1,2-diaminocyclohexane)(oxalato)(mononitrochloro)platinum(IV) is a particularly good anticancer agent and has been patented internationally. All these complexes were characterized using mass spectrometry, chromatography, thermogravimetric analysis, kinetic aspects such as ligand exchange rates and finally their anticancer action against three different cancer cell lines was evaluated via cytotoxicity assays. Some of the compounds exhibited particularly good anticancer potential.

Serious cardiovascular side effects are reported from synthetic cyclooxygenase-2 (COX-2) selective nonsteroidal anti-inflammatory drugs, the most common medication for rheumatoid arthritis (RA) and osteoarthritis (OA). Natural products from herbal medicine are inspirational source of safe and effective remedy due to its distinguished chemical diversity. Nanomagnetic ligand fishing using enzyme-anchored-magnetic nanoparticles (MNPs) is an advanced selective bioseparation strategy based on macromolecular target-ligand binding, which can screen enzyme inhibitors from complex mixtures. "Snow lotus" herbs have been clinically applied as safe and effective treatment for arthritis throughout centuries in Asia. Some major chemicals from the herbs have been found with anti-COX-2 activities. It is therefore hypothesized that novel and safe COX-2 selective inhibitors can be separated from a most representative snow lotus herb via ligand fishing using COX-2-functionalized MNPs (COX-2-MNPs), and that the efficacy and safety of the screened COX-2 ligands can be verified by subsequent evaluation. Saussurea laniceps Hand.-Mazz. (SL), S. medusa Maxim. (SM) and S. involucrata (Kar. et Kir.) Sch.Bip. (SI) are three authenticated sources of "snow lotus" herbs. An ultra-high performance liquid chromatography hyphenated with diode array detector and quadrupole time of flight-mass spectrometry (UPLC-DAD-QTOF-MS) method was developed to analyze 49 herbal samples for species analysis and overall quality evaluation. With 25 simultaneously identified constituents, of which 12 were quantified, the chemical determination, four-dimensional principle component analysis (4D-PCA), and orthogonal hierarchical cluster analysis (2D-HCA) showed a distinctive bioactive component profile of SL from the other two species, and explained the therapeutic potency of SL. As a result, SL has been chosen as a model herb to screen for novel and safe COX-2 selective inhibitors. With systematic uniform experimental designs and statistical modeling, COX-2-MNPs with high magnetic moments and outstanding enzyme activity have been synthesized. Four COX-2-selective compounds, namely, chlorogenic acid, syringin, umbelliferone, and scopoletin, were separated from the herbal extract using fine-tuned fishing protocol and were identified by UPLC-DAD-QTOF-MS. All the four ligands were proved with evidently lower in vitro and in vivo cardiotoxicity than celecoxib, a known selective COX-2 inhibitor. Some of them exerted potent anti-inflammatory activities on cells, and their optimum combination ratios were investigated. Among the ligands, scopoletin showed most evident therapeutic potential in rats with adjuvant-induced arthritis and anterior cruciate ligament transection (ACLT)-induced OA, respectively, by alleviating clinical statuses, immune responses, and joint pathological features. An equal mixture of scopoletin and syringin brought possible synergistic remedial effects on rat OA. Molecular docking results explained the structure-specific enzyme-binding affinities of the ligands; the ligands' inhibition on COX-2 may involve direct interaction as well as upstream signaling pathways. In conclusion, promising candidates of COX-2 selective inibitors, e.g. scopoletin, have been screened and validated on a nanomagnetic ligand fishing platform using COX-2-MNPs from the extract of SL, a most representative snow lotus herb with distinctive chemical composition and outstanding therapeutic efficacies. The quality evaluation strategy of snow lotus herbs combining chemical determination and multidimensional chemometric analysis can be applied in other multi-original herbal medicines. The nanomagnetic ligand fishing platform of compound bio-separation and multi-model bio-evaluation should be equally valuable for uncovering other therapeutic chemicals in different natural sources.

Thesis (MSc)--Stellenbosch University, 2003. / ENGLISH ABSTRACT: Advances in pharmacology, biochemistry and biotechnology are increasingly dependant upon affinity chromatography as a preferred separation technique for the purification and characterisation of specific biomolecules. In the past few years avidin-biotin technology has been widely and successfully used in the fields of medicine, pharmacy, biology and biochemistry. The avidin-biotin complex (ABC) has been used as a mediator for affinity chromatography, affinity cytochemistry, immunoassay, histopathology, bioaffinity sensors, erosslinking and immobilisation studies. The main reason for the popularity of the ABC and its growing usefulness in biotechnology is the exceptionally high affinity (1015 M-l) and stability of the noncovalent interaction between avidin and biotin. The use of the ABC is broadening as different biotin derivatives and avidin-containing conjugates are becoming commercially available. The aim of this work was to evaluate the usefulness of a plutonic" FI 08 and the ABC conjugate to effect affinity separation. Towards this aim, the adsorption of plutonic" F108 onto hydrophobic polysulphone membrane surfaces was studied. This information was used to determine the theoretical maximum amount of pluronic" FI08 that will adsorb onto a unit surface area of the membrane. It is known that the polypropylene oxide (PPO) centre block ofthe pluronic" F I08 surfactant molecule governs the concentration of pluronic" F I 08 molecules that will adsorb onto a given hydrophobic surface. If the maximum coating concentration of plutonic" FI08 is known, one can assume that the maximum coating concentration of any pluronic derivative, with the same PPO centre block size, will be the same. Adsorption studies were carried out, the Langmuir adsorption isotherm was determined, and subsequently the fractional coating was calculated. The end-groups of plutonic" FI08 were modified as follows and the substituted pluronic was adsorbed onto a membrane that was to act as the solid support matrix in the development of an affinity system: Amino pluronic was synthesised by first tosylating pluronic" FI08, followed by azidation with NaN3 then reduction with LiAI~. The synthesised amino pluronic was then biotinylated using N-hydroxysuccinimide biotin ester. The suitability of this synthetic route was first assessed on a model compound, 2-methoxyethylamine, and validated by NMR (Nuclear Magnetic Resonance) spectroscopy. The synthetic protocol was then used to derivatise the larger pluronic molecule. The affinity system was tested on two different hydrophobic surfaces: polystyrene and polysulphone membranes (PSMs). Avidin-conjugated horseradish peroxidase was obtained and used to interact with the immobilised biotin. The enzymatic reaction of the coupled peroxidase converted the substrate, 2, 2'-azino-di-(3-ethyl-benzthiazoline-6-sulphonic acid) (ABTS) to a coloured product. The colour developed is proportional to the amount of biotin that was immobilised on the hydrophobic surfaces studied. Non-covalent immobilisation of the synthesised biotin-pluronic molecule was successfully obtained onto the hydrophobic polystyrene as well as the polysulphone membrane surfaces. / AFRIKAANSE OPSOMMING: Vooruitgang in die farmakologie, biochemie en biotegnologie word al meer afhanklik van affiniteits chromatografie as die verkose tegniek vir die suiwering en karaterisering van spesifieke biomolekules. Oor die afgelope jare het die avidien-biotien tegnologie homself as baie bruikbaar bewys in die mediese, farmakologiese, biologiese en biochemiese velde. Toepassings waar die avidien-biotien kompleks betrokke was sluit in die toepassing as 'n mediator vir affiniteits chromatografie, affiniteits sitologie, immuno bepalings, histopatologie, bioaffiniteits sensors sowel as kruisbinding en immobiliserings studies en vele meer. Die hoofrede vir die gewildheid van die avidien-biotien kompleks en die groeiende bruikbaarheid in die biotegnologie is die buitengewone hoë affiniteit (l015 M-I ) en stabiliteit van die nie-kovalente interaksie tussen avidien en biotien. Die toepassingsveld van die avidien-biotien kompleks word wyer met die verskeidenheid biotien derivate en avidien-bevattende konjugate wat kommersiëel beskikbaar is. Die doel van die werk wat hier gedokumenteer word is om die bruikbaarheid van Plutonic" FI08 en die avidien-biotien kompleks, vir gebruik in 'n affiniteits chromatografie sisteem, te evalueer. Om hierdie doel te bereik is die adsorpsie van Pluronic" FI08 aan hidrofobiese polisulfoon membraan oppervlaktes bestudeer. Die eksperimentele data wat gegenireer is, is gebruik om die teoretiese maksimum hoeveelheid Pluronic wat per eenheids oppervlakte membraan adsorbeer te bepaal. Dit is reeds bekend dat die polipropileen (PPO) middel blok van die Pluronic emulgant die konsentrasie van die geadsorbeerde Pluronic molekules op 'n gegewe hidrofobiese oppervlakte bepaal. Indien die maksimum bedekkingskonsentrasie VIr maksimum oppervlakbedekking van Plutonic" FI08 bekend is, kan teoreties aanvaar word dat die bedekkingskonsentrasie vir enige Pluronic derivaat met dieselfde grootte PPO blok dieselfde sal wees. Adsorpsiestudies was uitgevoer om die Langmuir adsorpsie isoterm te bepaal. Daaropvolgend was die fraksionele bedekking bereken. Amino-pluronic was gesintetiseer deur die eindpunte van Pluronic te derivatiseer. Hierdie Pluronic derivaat was gevolglik geadsorbeer aan 'n membraan wat gedien het as die soliede oppervlakte vir die ontwikkeling van 'n affiniteits chromatografie sisteem. Amino-pluronic was gesintetiseer deur Pluronic eers te tosileer en daarna te asideer met NaN3 en laastens te reduseer met LiAI~. Die produk was gebiotinileer deur gebruik te maak van N-hidroksisuksinimied-biotien-ester. Die bruikbaarheid van hierdie sintetiese roete is eers bepaal deur van 'n model verbinding, 2-metoksiëtielamien, gebruik te maak en dit met behulp van KMR (Kern Magnetiese Resonans) spektroskopie te karakteriseer. Die affiniteits sisteem is getoets op twee verskillende hidrofobiese oppervlaktes naamlik polistireen en polisulfoon membraan oppervlaktes. Avidien gekonjugeerd met 'n peroksiedase ensiem is gebruik om met die geïmmobiliseerde biotien te assosieer. Die ensiematiese reaksie van die gekoppelde peroksiedase het die substraat 2, 2' -azino-di-(3-etiel-benzthiazolien-6-sulfoonsuur) (ABTS) omgesit na 'n gekleurde produk, waar dit teenwoordig is. 'n Reeks wasstappe is gebruik om die gemodifiseerde peroksidase ensiem wat nie aan die hidrofobiese oppervlakte gekoppel nie, weg te spoel. Hierdeur is die mate van binding aan die hirofobiese oppervlakte gekwantifiseer deur die kleur te kwantifiseer wat ontwikkelomdat die kleurontwikkeling direk proporsioneel is aan die hoeveelheid peroksidase wat nog aan die membraan gekoppel is. Nie-kovalente immobilisasie van die gesintetiseerde biotien-pluronic molekule is suksesvolop beide die hidrofobiese polistireen oppervlakte sowel as die polisulfoon membraan verkry.

Thesis (MSc)--Stellenbosch University, 2002. / ENGLISH ABSTRACT: Inthis work we aim to put into place a system to separate or immobilise biomacromolecules by means ofimmobilised transition metal ions like nickel(II) or copper(II). Although the concept of immobilised metal affmity chromatography (IMAC) has been around since the early 1960's, the metal ions were always immobilised by covalent modification of the support matrix. Recently the concept of IMAC was applied to membranes, and again the metal ion was immobilised by covalent modification of the membrane surface. Inthis study we covalently modified the support matrix by attaching a linear, EDTA type ligand to the hydroxy end groups of a tri-block copolymer (polyethylene oxide (PEO)m = 129 - polypropylene oxide (PPO)n = 56 - polyethylene oxide (PEO)m= 129), Pluronic® F108. The middle block of this polymer, which is hydrophobic, will non-covalently adsorb onto the membrane surface through hydrophobic interaction. The hydrophilic outer blocks, with the ligand modified end groups, will associate with the aqueous substrate exposing the chelated metal ion for interaction with the bio-macromolecules. This affords a system which is recyclable, without replacing the membranes, simply by stripping the expired ligand modified-polymer and adsorbing fresh polymer. A series of model ligands and their complexes were synthesised and characterised, to study the coordination of the ligand around the metal ions. The model compounds were also essential in characterising the final product - the ligand modified Pluronic. Finally the ligand modified Pluronic was tested for its metal binding capabilities. This was done in aqueous solution by qualitatively comparing the UV-VIS spectra of the modified Pluronic with that of the model ligands and complexes. The spectra indicate that metal coordination does take place. / AFRIKAANSE OPSOMMING: In die studie het ons beoog om 'n sisteem daar te stel vir die skei en immobilisering van bio-makromolekules deur middel van oorgangsmetale soos nikkel(II) en koper(II). Alhoewel die beginsel van geïmmobiliseerde Metaal-ioon Affmiteits Chromatografie (IMAC) reeds sedert die vroeë 1960's bekend is, is die metaal ione geïmmobiliseer deur kovalente modifikasie van die draermaterial. Onlangs is die beginsel van IMAC uitgebrei na membrane en ook hierin is die metaalione geïmmobiliseer deur kovalente modifikasie van die membraanoppervlaktes. In die projek het ons die draermateriaal kovalent gemodifiseer deur 'n lineêre EDT A-tipe ligand te koppel aan die hidroksie eindgroepe van 'n tri-blok ko-polimeer (poli-etileen oksied (PEO)m = 129 - poli-propileen oksied (PPO)n = 56 - poli-etileen oksied (PEO)m = 129), Pluronic® FI08. Die middelste blok van die polimeer, wat hidrofobies is, sal nie-kovalent aan die membraan oppervlakte adsorbeer d.m. v hidrofobiese interaksie. Die hidrofiliese buite blokke, met die ligand-gemodifiseerde eindgroepe, sal assosieer met die waterige substraat en die metal ioon blootstel vir interaksie met die biomakromolekules. Dit stel dus 'n sisteem in plek wat herbenut kan word, sonder om die membrane te vervang, deur eenvoudig die ligand-gemodifiseerde polimeer wat verval het te stroop en te vervang met nuwe polimeer. 'n Reeks modelligande en hul komplekse was gesintetiseer en gekarakteriseer om die koördinasie van die ligande rondom die metaal ione te bestudeer. Dié model verbindings was van groot belang in die karakterisering van die finale produk - die ligand-gemodifiseerde Pluronic. Laastens is die ligand-gemodifiseerde Pluronic getoets vir sy metaal bindings vermoeë. Dit is gedoen deur die UV-VIS spectra van die gemodifiseerde Pluronic kwalitatiefte vergelyk met die spectra van die modelligande en komplekse, in waterige oplossings. Die spectra dui aan dat metaalbinding wel plaasvind.

published_or_final_version / Chemistry / Doctoral / Doctor of Philosophy