Chemistry of Bryophytes Ge Xiaowei
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View metadata, citation and similar papers at core.ac.uk brought to you by CORE provided by ScholarBank@NUS CHEMISTRY OF BRYOPHYTES GE XIAOWEI (M.Sc., CHINESE ACADEMY OF PREVENTIVE MEDICINE) A THESIS SUBMITED FOR THE DEGREE OF DOCTOR OF PHILOSOPHY DEPARTMENT OF CHEMISTRY NATIONAL UNIVERSITY OF SINGAPORE 2007 ACKNOWLEDGEMENTS First of all, I would like to gratefully acknowledge the enthusiastic supervision of Professor Leslie J. Harrison throughout the duration of this project. Without his encouragement and patience, nothing would be possible. Also thanks to Professor Benito C. Tan for identification of the plant materials and many instructions during my research. Several people have been instrumental in allowing this project to be completed. I would like to thank especially Madam Han Yan Hui and Miss Ler Peggy from NMR laboratory, Madam Wong Lai Kwai and Madam Lai Hui Ngee from mass spectrometer laboratory, and Ms Tan Geok Kheng from X-Ray laboratory. Thanks them for their assistance with all types of technical problems at all time. I am also grateful to my friends Dr. Wang Yan Mei, Ms Teo Ee Ling, Zhang Guo Dong, Li Wei, and Huang Ming Xing for their discussions, suggestions and happy hours with them. Thanks to National University of Singapore to award me the research scholarship. Finally, I am forever indebted to my families, my wife, my son, and my parents for their endless understanding, patience, support and love. ii Contents Chapter 1. Introduction 1 1.1 Natural products in drug discovery 2 1.2 Natural products in chemical ecology 3 1.3 New technologies and strategies in natural product studies 4 1.3.1 New technologies in natural product chemistry 7 1.3.2 Sources of novel natural products 8 1.3.3 Biotechnologies in natural product chemistry 11 1.4 Natural products from bryophytes 13 1.4.1 Natural products from Mosses 14 1.4.2 Natural products from liverworts 21 Chapter 2. Natural products from some moss species 24 2.1 Suborder Dicranineae Fleisch 26 2.1.1 Family Dicranaceae, Dicranoloma blumii (Nees) Par. and Dicranoloma assimile (Hampe) Par. 26 2.1.2. Family Leucobryaceae, Leucobryum sanctum (Brid.) Hampe 39 2.2 Suborder Leucodontineae, Family Neckeraceae, Himantocladium cyclophyllum (C. Müll) Fleich 44 2.3 Suborder Hypnineae 54 2.3.1 Family Hypnaceae, Ectropothecium sparsipilum (Bosch & Lac.) Jaeg 54 iii 2.3.2 Family Hylocomiaceae, Rhytidiadelphus squarrosus (Hedw.) Wasmst 58 2.4 Suborder Grimmiineae, Family Grimmiaceae, Racomitrium lanuginosum (Hew.) Brid. 61 2.5 Suborder: Bryineae, Family Rhizogoniaceae, Pyrrhobryum spiniforme (Hedw.) Mitt. and Suborder Hypnineae, Family Hylocomiaceae, Pleurozium schreberi (Brid.) Mitt. 67 2.6 Order: Polytrichales, Family Polytrichaceae, Polytrichum commune Hedw 72 2.7 Conclusions 81 Chapter 3. Natural products from some liverwort species 83 3.1 Jungermanniidae 85 3.1.1 Riccardia crassa (Schwaegr.) C. Massal, Riccardia elata (Steph.) Schiffn., and Riccardia graeffei (Steph.) Hewson 85 3.1.2 Unidentified Malaysian Bazzania species 100 3.1.3 Lepidozia chordulifera Lindenb 107 3.1.4 Ptychanthus striatus (Lehm. & Lindenb.) Nees 116 3.1.5 Blepharostoma trichophyllum (L.) Dumort 123 3.1.6 Balantiopsis erinacea (Tayl.) Mitt 136 3.1.7 Cryptochila grandiflora (Lindenb. & Gott.) Grolle 143 3.2 Marchantiidae 154 3.2.1. Preissia quadrata (Scop.) Nee 154 3.3 Conclusion 159 iv Chapter 4 Chemosystematics of mosses and liverworts 160 References 164 v SUMMARY In this thesis, the chemistry of twenty-four bryophyte species has been studied. A combination of chromatographic methods was used to isolate thirty-seven new and thirty- four known compounds. The structures of these compounds were elucidated using a combination of techniques, such as NMR, MS, XRD, and chemical modifications. These compounds include flavonoids, terpenoids, bibenzyls, simple phenolic compounds, and some very specific aromatic compounds. Chapter One briefly introduces the background of this project including natural products in ecology and drug discovery. New technologies and strategies in natural product studies, such as LC-NMR, Computer-Assisted Structure Elucidation (CASE) systems, new sources of natural products such as One Strain–Many Compounds (OSMAC), biotransformation, and some biochemistry methods, are also outlined. Finally, the natural products from bryophytes are described. Chapter Two mainly includes the chemical studies of ten moss species from which seventeen new and ten known compounds were isolated. Phenanthrene derivatives, such as dicranopyran (10-hydroxy-5-methoxy-2,2-dimethyl-2H-phenanthro[4,3-b]pyran) and another five similar compounds, were found in Dicranoloma blumii and Racomitrium lanuginosum. Ohioensins, pallidisetin A [(9E)-2,3-dihydro-2-phenyl-5-styrylchromen-4- one], pallidisetin B (2,3-dihydro-2-phenylnaphtho[2,1-f]chromen-4-one), and communin A [(9Z)-2,3-dihydro-2-phenyl-5-styrylchromen-4-one] were isolated from Polytrichum commune. Himantocladium cyclophyllum produced the unique biflavonoid vi himantoflavone, which contained one flavone moiety and one isoflavone moiety. 3′,3′′′- Binaringenin methyl ethers were obtained from Ectropothecium sparsipilum. Pyrronin (5- phenyl-5H-naphtho[1,2-c]-chromene-1,3-diol) was found in Pyrrhobryum spiniforme and Pleurozium schreiberi and leuconin [4,7,9-trihydroxy-1-(4-hydroxyphenyl)-6H-anthra- [1,9-bc]-furan-6-one] was isolated from Leucobryum sanctum. Chapter Three is concerned with twenty new and twenty-four known compounds from ten liverwort species. Most of them are terpenoids, flavonoids, and bisbibenzyls. Two bisbibenzyl acids, blepharonins A and B from Blepharostoma trichophyllum and three chlorinated bisbibenzyls (2,10,12,6',14'-pentachloroisoplagiochin C, 2,12,14'- trichloroisoplagiochin C-1'-methyl ether, 2,10,12,14'-tetrachloroisoplagiochin C-1'- methyl ether) from Lepidozia chordulifera are the most interesting compounds. Chapter Four briefly discusses the use of the chemistry of bryophytes in taxonomy. The results showed that the chemistry of bryophytes could provide taxonomic supporting information at class or subclass level. vii List of Tables Table 1-1, Biflavonoids from Moss Species Table 2-1, The classification of Bryopsida Table 2-2, 1H, HMBC, NOESY and 13C NMR data for compound 89 Table 2-3, 1H, HMBC, NOESY and 13C NMR data for compound 92 Table 2-4, 1H, HMBC, NOESY and 13C NMR data for compound 93 Table 2-5, 1H, HMBC, NOESY and 13C NMR data for compound 94 Table 2-6, 1H, HMBC, and 13C NMR data for compound 95 Table 2-7, 1H, HMBC, and 13C NMR data for compound 99 Table 2-8, 1H, HMBC, and 13C NMR data for compound 105 Table 2-9, 1H, HMBC, and 13C NMR data for compound 107 Table 2-10, 1H, HMBC, and 13C NMR data for compound 109 Table 2-11, 1H, HMBC, NOESY and 13C NMR data for compound 110 Table 2-12, 1H, HMBC, NOESY and 13C NMR data for compound 111 Table 3-1, The classification of Hepatophyta Table 3-2, 1H, HMBC, and 13C NMR data for compound 133 Table 3-3, 1H, HMBC, and 13C NMR data for compound 164 Table 3-4, 1H, HMBC, and 13C NMR data for compound 176 Table 3-5, 1H, HMBC, and 13C NMR data for compound 177 Table 3-6, 1H, HMBC, and 13C NMR data for compound 178 Table 3-7, 1H, HMBC, and 13C NMR data for compound 191 Table 3-8, 1H, HMBC, and 13C NMR data for compound 200 viii Table 3-9, 1H, HMBC, and 13C NMR data for compound 226 Table 3-10, 1H, HMBC, and 13C NMR data for compound 228 Table 3-11, 1H, HMBC, and 13C NMR data for compound 229 Table 3-12, 1H, HMBC, and 13C NMR data for compound 230 ix List of Figures Figure 1-1, Overview of isoprenoid biosynthesis and compartmentation in plants Figure 2-1, Taxonomy of studied moss species Figure 2-2, Selective HMBC correlations of 89 Figure 2-3, Selective HMBC correlations of 92 Figure 2-4, Selective HMBC correlations of 93 Figure 2-5, Selective NOE effects of 93 Figure 2-6, Selective HMBC correlations of 94 Figure 2-7, Selective NOE effects of 94 Figure 2-8, Selective HMBC correlations of 95 Figure 2-9, Selective HMBC correlations of 99 Figure 2-10, Selective NOE effects of 100 Figure 2-11, Selective HMBC correlations of 104 Figure 2-12, Selective NOE effects of 101, 102 and 103 Figure 2-13, Selective HMBC correlations of 107 Figure 2-14, Selective HMBC correlations of 109 and 110 Figure 2-15, Selective NOE effects of 109 and 110 Figure 2-16, Selective HMBC correlations of 111 Figure 3-1, Taxonomy of studied liverwort species Figure 3-2, Selective HMBC correlations and relative configuration of 133 Figure 3-3, Relative configuration and selective NOE effects of 135 Figure 3-4, Selective HMBC correlations of 164 x Figure 3-5, Selective NOE effects of 164 Figure 3-6, Selective HMBC correlations of 176 Figure 3-7, Selective HMBC correlations of 191 Figure 3-8, Selective NOE effects of 191 Figure 3-9, Selective HMBC correlations of 198 Figure 3-10, Selective HMBC correlations of 200 Figure 3-11, Selective NOE effects of 200 Figure 3-12, ORTEP drawing of pyridinium part of 227 Figure 3-13, ORTEP drawing of 229 xi List of Schemes Scheme 2-1, Proposed biogenesis of 94 Scheme 2-2, Proposed biogenesis of 107 Scheme 2-3, Proposed biogenesis of 109-112 Scheme 2-4, Phenolic compounds from moss species Scheme 3-1, Proposed biogenesis of 191 Scheme 3-2, Formation of the p-bromobenzenesulphate salt 227 Scheme 3-3, Methanolysis of 231 to 230 xii List of abbreviations CC: Column Chromatography COSY: Correlation Spectroscopy DMAPP: Dimethylallyl diphosphate DXP: 1-deoxy-D-xylulose-5-phosphate EIMS: Electron Impact Mass Spectrometry ESIMS: Electrospray Ionization Mass Spectrometry eV: electron Volt FPP: Farnesyl