Este trabalho descreve a utilização dos programas do sistema especialista denominado SISTEMAT, avaliando a sua eficiência para auxiliar os pesquisadores da área de Produtos Naturais no processo de determinação estrutural de sesquiterpenos, a partir de dados de RMN 13C. Os principais sistemas especialistas em determinação estrutural operam, basicamente, combinando fragmentos estruturais, chamados \"restrições estruturais\", obtidos a partir de dados espectroscópicos. Ocorre que para moléculas complexas (com mais do que 15 átomos), o número de propostas estruturais geradas é muito grande, sendo necessária a ajuda do químico para eliminar estruturas improváveis. Este fato demonstra a necessidade de grandes restrições estruturais para o bom funcionamento do programa gerador, como por exemplo, a definição de classe e esqueleto, que foram utilizadas no desenvolvimento do SISTEMAT. O SISTEMAT foi criado especificamente para determinação estrutural de substâncias de origem natural, sendo desenvolvidas técnicas para obtenção de regras heurísticas, a partir de dados de RMN13C, que permitam a identificação de esqueletos de produtos naturais. Estes serão usados como grandes restrições pelo gerador de estruturas, evitando-se, assim, a explosão combinatória e a geração de propostas estruturais incompatíveis. Para a realização deste trabalho foi criado um banco de dados contendo os deslocamentos químicos e multiplicidades de 2306 espectros de sesquiterpenos, distribuídos entre substâncias pertencentes a 288 tipos de esqueletos. Estes dados são analisados pelos vários programas aplicativos do SISTEMAT, sendo fornecidos os esqueletos mais prováveis para uma substância-problema e grandes subestruturas compatíveis com o espectro analisado. Para avaliar o desempenho do sistema foram realizados testes com dados de RMN 13C de 60 sesquiterpenos. A aplicação do SISTEMAT na identificação de sesquiterpenos em misturas, como por exemplo, em óleos essenciais, também foi investigada pela primeira vez, com resultados promissores. / The present work describes the use of the expert system programs called SISTEMAT, evaluating their efficacy at helping Natural Products researchers to determine the structure of sesquiterpenes, using 13C-NMR spectroscopy data. The major expert systems for structural determination operate by combining structural fragments called \"structural restrictions\", obtained from spectroscopic data. For complex molecules (bearing more than 15 atoms), the number of proposed structures becomes too large, hence the imposition of external chemical knowledge is required, in order to exclude improbable structures. This fact demonstrates the need of large structural restrictions to be imposed to get acceptable results output by the generator program. The definition of class and skeleton, which were used during the development of SISTEMAT, are examples of such restrictions. SISTEMAT was created specially for natural products structural determination and methods were developed to obtain heuristic rules, mainly from 13C-NMR data, which allow the identification of natural products skeletal types. These will be used as large restrictions by the generator of structures, in order to avoid a combinatory explosion process at the generation step of the system. To reach the purpose of this work a data base was created with 2306 13C-NMR spectra of sesquiterpenes, distributed in 288 skeletal types. Those data are used by the set of SISTEMAT programs which propose the most probable skeleton for the unknown sesquiterpene together with some large substructures compatible with the analysed spectrum. To evaluate the efficacy of the system, tests were carried out with the RMN 13C data from 60 sesquiterpenes. The application of SISTEMAT in the identification of sesquiterpenes in neat essential oils was also investigated for the first time with promising results.

by Xiao-Ping Cao. / Thesis (Ph.D.)--Chinese University of Hong Kong, 1996. / Includes bibliographical references (leaves 119-126). / Acknowledgement --- p.i / Contents --- p.ii / List of Schemes --- p.iv / List of Tables and Figures --- p.v / List of Spectra --- p.vi / Abstract --- p.ix / Chapter Chapter 1. --- Introduction --- p.1 / Chapter Chapter 2. --- "1,2,3-Butatrienes" / Chapter 2.1. --- "Preparation of 1,2,3-Butatrienes" --- p.4 / Chapter 2.2. --- Our Synthetic Approach --- p.9 / Chapter 2.3. --- Results and Discussion --- p.10 / Chapter Chapter 3. --- "1,3,5-Hexatrienes" / Chapter 3.1. --- "Preparation of 1,3,5-Hexatrienes" --- p.16 / Chapter 3.2. --- Results and Discussion / Chapter 3.2.1. --- Preparation of Hexatrienes Using the Ramberg-Backlund Reaction --- p.24 / Chapter 3.2.2. --- Preparation of Stereoisomerically Pure Diallylic Sulfides and Sulfones --- p.29 / Chapter 3.2.3. --- The Stereochemistry of the Ramberg-Backlund Rearrangement of Diallylic Sulfones --- p.34 / Chapter 3.2.4. --- Effect of Solvent and Temperature on the Stereochemistry of the Newly Formed Double Bond --- p.38 / Chapter 3.2.5. --- Total Synthesis of Galbanolenes --- p.39 / Chapter 3.3. --- Conclusions --- p.41 / Chapter Chapter 4. --- Enediynes / Chapter 4.1. --- "Preparation of 3-Ene-l,5-diynes" --- p.42 / Chapter 4.2. --- Results and Discussion --- p.48 / Chapter Chapter 5. --- "1,3,5,7-Octatetraenes" / Chapter 5.1. --- "Preparation of 1,3,5,7-Octatetraenes" --- p.53 / Chapter 5.2. --- "Preparation of 1,3,5,7-Octatetraenes Using the Ramberg-Backlund Reaction" --- p.57 / Experimental --- p.64 / References --- p.119 / List of Publications Based on Research Reported in This Thesis --- p.127 / Spectra --- p.128

by Qin Jiang. / Thesis (Ph.D.)--Chinese University of Hong Kong, 1997. / Includes bibliographical references (p. 131-139). / Electronic reproduction. Hong Kong : Chinese University of Hong Kong, [2012] System requirements: Adobe Acrobat Reader. Available via World Wide Web. / Mode of access: World Wide Web. / Abstracts in English and Chinese.

by Pei Yu. / Thesis (Ph.D.)--Chinese University of Hong Kong, 1997. / Includes bibliographical references (p. 141-149). / Electronic reproduction. Hong Kong : Chinese University of Hong Kong, [2012] System requirements: Adobe Acrobat Reader. Available via World Wide Web. / Mode of access: World Wide Web. / Abstracts in English and Chinese.

Red maple (Acer rubrum), also known as swamp, water or soft maple, is endemic to eastern and central North America and was widely used as traditional medicine by the first peoples. Commercially, its well-known products include maple syrup and high-quality lumber. The potential medicinal benefits of phenolic compounds extracted from the red maple plant, such as glucitol-core containing gallotannins, include antioxidant, and antiglycation effects as well as their importance in cosmetic applications. Plant-derived proteins and peptides are important biomolecules; however to date, there is no published data on the identification of proteins/peptides from red maple leaves. Therefore, the present study focuses on the activity guided purification of proteins from red maple leaves collected in spring and fall seasons. In addition, the focus of this project was in the evaluation of maple leaves employing bottom-up proteomics and De Novo protein profiling by PEAKS Studio-X and Gene Ontology Bioinformatics. The red maple leaves were grounded, defatted in hexane and proteins extracted in 25 mM sodium phosphate buffer pH 6.5. The extracted crude proteins were recovered by precipitation in 80% ammonium sulfate. The first-dimensional chromatography of crude extracted proteins was performed on a gel filtration column (HiLoad 16/600 Superdex200). The separation of crude extract and the partially purified gel filtration fraction was conducted by reversed-phase HPLC. The crude and eluted fractions were analyzed by SDS-PAGE gel electrophoresis. The extract was screened for cytotoxicity activity on Michigan Cancer Foundation-7 breast cancer (MCF-7), M.D. Anderson Metastasis Breast (MDA-MB-231) cancer cell lines and anti-inflammatory activity on murine macrophage (RAW 264.7) cell line from American Type Culture Collection (ATCC). The drug Doxorubicin was used as a positive control whereas untreated cells as a negative control in these experiments Preliminary data revealed that active protein fractions were eluted at two different regions of gel filtration chromatography both in spring and fall leaves. Bottom-up proteomics of crude and active fractions by PEAKS Studio-X and MASCOT bioinformatics database identified over 54 proteins. The Gene Ontology Annotation classified these proteins involved in the biological processing, cellular compartment, and molecular functions.

Thesis (Ph.D.)--York University, 2004. Graduate Programme in Chemistry. / Typescript. Includes bibliographical references (leaves 167-179). Also available on the Internet. MODE OF ACCESS via web browser by entering the following URL: http://wwwlib.umi.com/cr/yorku/fullcit?pNQ99174

The Chinese herb Artemisia annua possesses small 10-cell biseriate glandular trichomes on the surface of its aerial tissues. These trichomes were isolated from floral tissue using a Bead Beater based method. Expression patterns of expressed sequence tags from a trichome library whose Basic Local Alignment Search Tool (BLAST) results suggested a possible function in terpenoid metabolism were investigated by RT-PCR. Known terpenoid biosynthetic enzymes, such as amorpha-4,11-diene synthase showed a high degree of trichome-specific expression. In order to investigate cell specific gene expression within the trichome, the promoter for the gene encoding amorpha-4,11-diene synthase was isolated but the lack of an efficient transformation protocol in A. annua hindered reporter gene localization experiments. Traditional and whole-mount <i>in situ</i> hybridization techniques were used to further the study of cell specific gene expression within the glandular trichome. An RNA probe constructed from the sequence of amorpha-4,11-diene synthase localized expression to the 2nd and 3rd subapical cell pairs of the glandular trichomes. This suggests that at least part of the artemisinin biosynthetic pathway resides within the lower cell pairs. To better understand the genes involved in terpenoid biosynthesis in A. annua, the full length sequence of a short chain alcohol dehydrogenase highly represented in an expressed sequence tag library and shown to have trichome-specific expression by RT-PCR, was cloned. Heterologous expression in Escherichia coli demonstrated that the enzyme was capable of oxidizing a wide range of monoterpenols to their corresponding ketone forms. All of this data helps us to better understand the organization of expression and biochemistry of terpenoids in A. annua glandular trichomes.

The Chinese herb Artemisia annua possesses small 10-cell biseriate glandular trichomes on the surface of its aerial tissues. These trichomes were isolated from floral tissue using a Bead Beater based method. Expression patterns of expressed sequence tags from a trichome library whose Basic Local Alignment Search Tool (BLAST) results suggested a possible function in terpenoid metabolism were investigated by RT-PCR. Known terpenoid biosynthetic enzymes, such as amorpha-4,11-diene synthase showed a high degree of trichome-specific expression. In order to investigate cell specific gene expression within the trichome, the promoter for the gene encoding amorpha-4,11-diene synthase was isolated but the lack of an efficient transformation protocol in A. annua hindered reporter gene localization experiments. Traditional and whole-mount <i>in situ</i> hybridization techniques were used to further the study of cell specific gene expression within the glandular trichome. An RNA probe constructed from the sequence of amorpha-4,11-diene synthase localized expression to the 2nd and 3rd subapical cell pairs of the glandular trichomes. This suggests that at least part of the artemisinin biosynthetic pathway resides within the lower cell pairs. To better understand the genes involved in terpenoid biosynthesis in A. annua, the full length sequence of a short chain alcohol dehydrogenase highly represented in an expressed sequence tag library and shown to have trichome-specific expression by RT-PCR, was cloned. Heterologous expression in Escherichia coli demonstrated that the enzyme was capable of oxidizing a wide range of monoterpenols to their corresponding ketone forms. All of this data helps us to better understand the organization of expression and biochemistry of terpenoids in A. annua glandular trichomes.

Marine natural products have continued to be a source of compounds with interesting structures and biological activities. Two such compounds are maculalactone A and haterumalide NA. In the process of exploring a route to the synthesis of haterumalide NA, the novel ring system, spiroepoxy-b-lactones were discovered. Spiroepoxy-b-lactones were synthesized by the oxidation of ketene-homo dimers with dimethyldioxirane (DMDO). After a synthetic route to this ring system was obtained we next explored the varied reactivity of spiroepoxy-b-lactones, and it was apparent that they might be applied to the synthesis of maculalactone A. Also with the aim of the total synthesis of the haterumalides, a palladium catalyzed cross coupling was developed. This reaction couples a 1,1-dichloroolefin with an alkyl zinc reagent. It was found that this reaction necessitates a heteroatom on the zinc reagent in order to proceed.

Thesis (Ph. D.)--University of Queensland, 2003. / Includes bibliographical references.