Tripterygium wilfordii (T. wilfordii , TW ), a wildly used herb medicine,was tested for anticancer effect on human myeloid leukemia cells, HL60 in this study. The extract powder of T. wilfordii induced the apoptosis of HL60 cells was demonstrated by morphological change, cell viability, DNA fragmentation and caspase-3 activity. However, normal human peripheral mononuclear cells remained viable under the same treatment. The T. wilfordii induced apoptosis of HL60 cells was associated with the increased Bax gene expression and decreased Bcl-2 gene expression. In addition, the gene expression of c-Myc, and hTERT, TP1, but not TR was downregulated in TW treatedHL60 cells in dose-dependent manner. Telomerase activity in HL60 cell was inhibited by the T. wilfordii . C-Myc protein is reported as a positive regulator of hTERT gene in HL60 cells. Therefore, proto-oncogene c-myc might play an essential role in the regulation of telomerase activity in HL60cells exposed to theT. wilfordii . All the treated cells showed a decrease in telomerase activity after T. wilfordii treatment. Taken togather, these results indicate that theT. Wilfordii-induced apoptosis in HL60 is mediated through mitochondrial pathway in parallel with the decrease expression of hTERT gene.

Law Ka Yee. / Thesis (M.Phil.)--Chinese University of Hong Kong, 2006. / Includes bibliographical references (leaves 214-225). / Abstracts in English and Chinese. / ACKNOWLEDGEMENTS --- p.I / ABSTRACT --- p.II / TABLE OF CONTENTS --- p.VII / LIST OF FIGURES --- p.X / LIST OF TABLES A --- p.XII / APPENDIX --- p.XIII / Chapter CHAPTER ONE --- LITERATURE REVIEW --- p.1 / Chapter 1.1 --- Chinese herbs --- p.1 / Chapter 1.1.1 --- Introduction --- p.1 / Chapter 1.1.2 --- Leigongteng --- p.2 / Chapter 1.1.2.1 --- Leigongteng and its importance --- p.2 / Chapter 1.1.2.2 --- Chemical components and pharmacological effects of Leigongteng --- p.4 / Chapter 1.1.3 --- Problems in authentication of Leigongteng --- p.5 / Chapter 1.1.3.1 --- Taxonomic problems of Tripterygium --- p.5 / Chapter 1.1.3.2 --- Confusion caused by other species --- p.7 / Chapter 1.1..3.3 --- Adulterants --- p.9 / Chapter 1.2 --- Celastraceae --- p.10 / Chapter 1.2.1 --- Introduction --- p.10 / Chapter 1.2.2 --- Controversial taxonomic issue --- p.12 / Chapter 1.2.1.1 --- Subfamilies of Celastraceae --- p.12 / Chapter 1.2.1.2 --- Subfamily Tripterygioideae --- p.13 / Chapter 1.3 --- Molecular authentication --- p.14 / Chapter 1.4 --- Molecular systematics --- p.18 / Chapter 1.4.1 --- DNA sequence markers --- p.19 / Chapter 1.4.2 --- Molecular phylogeny --- p.25 / Chapter 1.4.2.1 --- Tree-building method --- p.25 / Chapter 1.4.2.2. --- Measures of support --- p.28 / Chapter 1.5 --- Objectives --- p.29 / Chapter CHAPTER TWO --- MATERIALS AND METHODS --- p.31 / Chapter 2.1 --- Plant and herb samples --- p.31 / Chapter 2.2 --- DNA extraction --- p.41 / Chapter 2.2.1 --- Modified CTAB extraction --- p.41 / Chapter 2.2.2 --- Commercial kit extraction --- p.42 / Chapter 2.3 --- Polymerase chain reaction (PCR) condition --- p.43 / Chapter 2.4 --- DNA gel electrophoresis --- p.44 / Chapter 2.5 --- PCR product purification --- p.45 / Chapter 2.5.1 --- GEL-M´ёØ gel extraction system --- p.45 / Chapter 2.6 --- Ligation and transformation --- p.46 / Chapter 2.6.1 --- Ligation and transformation --- p.46 / Chapter 2.6.2 --- Cell cultivation --- p.47 / Chapter 2.6.3 --- Plasmid extraction --- p.47 / Chapter 2.7 --- Determination of DNA concentration --- p.49 / Chapter 2.8 --- Cycle sequencing --- p.49 / Chapter 2.9 --- Sequence analysis --- p.50 / Chapter 2.10 --- Materials preparation --- p.51 / Chapter CHAPTER THREE --- MOLECULAR AUTHENTICATION OF LEIGONGTENG --- p.54 / Chapter 3.1. --- Authentication based on internal transcribed spacer (ITS) region --- p.54 / Chapter 3.1.1 --- Sequence alignment --- p.54 / Chapter 3.1.2 --- ITS region nucleotide differences significant in authentication of Leigongteng --- p.55 / Chapter 3.1.3 --- Relationship of samples --- p.70 / Chapter 3.1.4 --- Comparison of sequences --- p.75 / Chapter 3.2 --- Authentication based on 5s-rDNA region --- p.78 / Chapter 3.2.1 --- Sequence alignment --- p.78 / Chapter 3.2.2 --- 5s-rDNA nucleotide differences significant in authentication of Leigongteng --- p.78 / Chapter 3.2.3 --- Relationship of samples --- p.88 / Chapter 3.2.4 --- Comparison of sequences --- p.90 / Chapter 3.3 --- Authentication based on psbA-trnH region --- p.93 / Chapter 3.3.1 --- Sequence alignment --- p.93 / Chapter 3.3.2 --- psbA-trnH nucleotide differences significant in authentication of Leigongteng --- p.101 / Chapter 3.3.3 --- Relationship of samples --- p.113 / Chapter 3.3.4 --- Comparison of sequences --- p.115 / Chapter 3.4 --- Authentication based on trnL-F region --- p.118 / Chapter 3.4.1 --- Sequence alignment --- p.118 / Chapter 3.4.2 --- trnL-F region nucleotide differences significant in authentication of Leigongteng --- p.121 / Chapter 3.4.3 --- Relationship of samples --- p.139 / Chapter 3.4.4 --- Comparison of sequences --- p.141 / Chapter 3.5 --- Discussion --- p.144 / Chapter 3.5.1 --- Molecular markers --- p.144 / Chapter CHAPTER FOUR --- PHYLOGENETIC STUDIES ON TRIPTERYGIUM --- p.151 / Chapter 4.1 --- Combine loci of ITS and 5s-rDNA regions --- p.152 / Chapter 4.1.1 --- Homogenity test --- p.152 / Chapter 4.1.2 --- Sequence alignment --- p.152 / Chapter 4.1.3 --- Phylogenetic study --- p.173 / Chapter 4.2 --- psbA-trnH region --- p.174 / Chapter 4.2.1 --- Sequence alignment --- p.174 / Chapter 4.3 --- Discussion --- p.177 / Chapter CHAPTER FIVE --- PHYLOGENETIC STUDIES ON TRIPTERYGIOIDEAE AND CELASTRACEAE --- p.191 / Chapter 5.1 --- ITS regions --- p.191 / Chapter 5.1.1 --- Sequence alignment --- p.191 / Chapter 5.1.2 --- Phylogenetic analysis --- p.205 / Chapter 5.2 --- Discussion --- p.206 / Chapter 5.2.1 --- Subfamily Tripterygioideae --- p.206 / Chapter 5.2.2 --- Subfamilies of Celastraceae --- p.210 / Chapter CHAPTER SIX --- CONCLUSION --- p.212 / BILBIOGRAPHY --- p.214

This thesis discusses the progress made towards a formal total synthesis of triptolide, a naturally occurring diterpenoid triepoxide molecule. Isolated from a Chinese vine, triptolide features some interesting structural characteristics and has demonstrated a broad range of interesting medicinal effects. It has demonstrated remarkable cytotoxicity against a number of cancer cell lines, immunosuppressive activity, and reversible male sterility. This biological activity has made it a target of a number of total syntheses spanning from 1980 to 2010. Gold-catalyzed transformations are an emerging field in synthetic organic chemistry, but their efficacy and potential uses are gaining much recognition among the synthetic organic community. Our research group is extremely interested in the applications of such gold-catalyzed organic transformations in natural product synthesis. Here, we discuss our investigations towards accessing the tetracyclic core of triptolide using a gold-catalyzed cyclization cascade reaction. We explored a number of synthetic routes towards a common linear precursor, and our successes and failures are discussed herein. We also report numerous unsuccessful efforts towards an oxidative gold-catalyzed cyclization cascade to form the tetracyclic core of triptolide. Finally, we investigated the use of a photocatalytic radical cyclization cascade to access the desired core. We report some promising preliminary results, and this study is ongoing in the Barriault group.

This thesis discusses the progress made towards a formal total synthesis of triptolide, a naturally occurring diterpenoid triepoxide molecule. Isolated from a Chinese vine, triptolide features some interesting structural characteristics and has demonstrated a broad range of interesting medicinal effects. It has demonstrated remarkable cytotoxicity against a number of cancer cell lines, immunosuppressive activity, and reversible male sterility. This biological activity has made it a target of a number of total syntheses spanning from 1980 to 2010. Gold-catalyzed transformations are an emerging field in synthetic organic chemistry, but their efficacy and potential uses are gaining much recognition among the synthetic organic community. Our research group is extremely interested in the applications of such gold-catalyzed organic transformations in natural product synthesis. Here, we discuss our investigations towards accessing the tetracyclic core of triptolide using a gold-catalyzed cyclization cascade reaction. We explored a number of synthetic routes towards a common linear precursor, and our successes and failures are discussed herein. We also report numerous unsuccessful efforts towards an oxidative gold-catalyzed cyclization cascade to form the tetracyclic core of triptolide. Finally, we investigated the use of a photocatalytic radical cyclization cascade to access the desired core. We report some promising preliminary results, and this study is ongoing in the Barriault group.