Addis Ababa University Science Faculty Chemistry Department Organic Stream Graduate Project - Chem. 774 Phytochemical Investigation of the Pods of Senna occidentalis Fekade Beshah Advisor: Dr. Gizachew Alemayehu(PhD) July 2008 Addis Ababa University Science Faculty Chemistry Department Organic Stream Phytochemical Investigation of the Pods of Senna occidentalis A graduate project submitted to the Department of Chemistry, Science Faculty, AAU Fekade Beshah Advisor: Dr. Gizachew Alemayehu(PhD) July 2008 Contents Acknowledgements ..................................................................................................................... v Abstract......................................................................................................................................... vi 1. Introduction .............................................................................................................................. 1 2. Senna occidentalis And Its Medicnal Uses ............................................................................. 6 3. Secondary Metabolites from Senna occidentalis.................................................................... 9 3.1 Preanthraquinones From Senna occidentalis .................................................................. 9 3.2 Anthraquinones From Senna occidentalis .................................................................... 10 3.3. Bianthraquinones From Senna occidentalis.................................................................. 11 3.4. Glycosides From Senna occidentalis.............................................................................. 12 4. Biosynthesis of Anthraquinones.......................................................................................... 13 5. Identification of Anthraquinones ........................................................................................ 17 5.1. Color reaction .................................................................................................................. 17 5.2. Spectroscopic Methods................................................................................................... 17 6. Objectives ................................................................................................................................ 21 7. Senna occidentalis..................................................................................................................... 21 8. Experimental Part .................................................................................................................. 23 8.1 General............................................................................................................................... 23 8.2 Extraction and Isolation: Chloroform Extract.............................................................. 24 8.3. Methanol Extract ............................................................................................................. 27 9. Result and Discussions.......................................................................................................... 28 9.1 General................................................................................................................................ 28 9.2 Isolation and Purification of Anthraquinones from the Chloroform Extract...................... 29 9.3. Characterization of Anthraquinones from the Chloroform Extract ........................ 32 10. Conclusion ........................................................................................................................... 38 11. Spectral Data......................................................................................................................... 39 12. References ............................................................................................................................. 40 13. Appendixes ........................................................................................................................... 46 ii List of tables Table 1. The major classes of phenolics in plants [2]............................................................... 4 Table 2. Preanthraquinones......................................................................................................... 9 Table 3. Anthraquinones from Senna occidentalis................................................................... 10 Table 4. Bianthraquinones from Senna occidentalis................................................................ 11 Table 5. Glycosides from Senna occidentalis............................................................................. 12 Table 6. Carbonyl frequencies of hydroxyanthraquinones [46].......................................... 18 Table 7. Peak multiplicity nomenclature [45]........................................................................ 20 Table 8. Comparison of the observed 1H NMR spectral data with reported value of physcion. ..................................................................................................................................... 33 Table 9. Comparison of the observed 1H NMR spectral data with reported value of emodin......................................................................................................................................... 34 Table 10. Comparisons of 13C NMR (400MHz) and DEPT 135 spectral data of emodin in acetone d6..................................................................................................................................... 35 Table 11. Comparison of the observed 1H NMR spectral data with reported value of 5,7`-biphyscion. .......................................................................................................................... 36 List of figures Figure 1. Anthraquinone skeleton and alizarin............................................................................... 4 Figure 2. Structures of preanthraquinones.................................................................................... 10 Figure 3. Representatives of bianthroaquinones.......................................................................... 11 Figure 4. Representatives of glycosides....................................................................................... 12 Figure 5. Sennosides , cascarosides and frangulins[43]....................................................... 16 Figure 6. Parts the plant Senna occidentalis [53]..................................................................... 21 Figure 7. TLC Spots. (a) Chloroform extract( in CHCL3: MeOH (19:1)), (b) first fractions of CC(Solvent 5) ............................................................................................................................... 27 Figure 8. TLC spots for comparison of fraction 8 and CEO-131 ................................................. 32 iii List of schemes Scheme 1. Acetate Pathway [43] .............................................................................................. 14 Scheme 2. Biosynthesis of endocrocin and emodin [43]...................................................... 15 Scheme 3. One electron oxidation of emodin anthrone [43]................................................ 16 Scheme 4. Extraction Summary ............................................................................................... 29 Scheme 5. Isolation and purification in the optimization step............................................ 30 Scheme 6. Isolation and purification in the main step.......................................................... 30 List of Appendixes 1 Appendix 1 . H NMR Spectrum for Physcion (6) in CDCl3 ..................................................... 46 Appendix 2. UV Spectrum in CDCl3 for Physcion compound (6).............................................. 47 Appendix 3. IR Spectrum for Physcion (6) in KBr ................................................................... 48 1 Appendix 4. H NMR Spectrum for Emodin (7) in CDCl3 ........................................................ 49 1 Appendix 5. H NMR Spectrum for Emodin (7) in Acetone d6 .................................................. 50 13 Appendix 6. C NMR Spectrum for Emodin(6) in Acetone d6 ................................................. 51 Appendix 7. DEPT- 135 Spectrum for Emodin(6) in Acetone d6 ............................................ 52 13 Appendix 8. C NMR and DEPT-135 Spectrum for Emodin(6) in Acetone d6 ......................... 53 Appendix 9. UV Spectrum in CDCl3 for Emodin (6)................................................................... 54 Appendix 10. IR Spectrum for Emodin (7) in KBr ................................................................... 55 1 Appendix 11. H NMR Spectrum for compound (37) in CDCl3 ................................................. 56 Appendix 12. UV Spectrum in CDCl3 for compound (37).......................................................... 57 Appendix 13. IR Spectrum for compound (37) in KBr ............................................................... 58 1 Appendix 14. H NMR Spectrum for compound (38) in CDCl3 ................................................ 59 Appendix 15. UV Spectrum in CDCl3 for compound (38)......................................................... 60 Appendix 16. IR Spectrum for compound (38) in KBr .............................................................. 61 iv Acknowledgements I wish to express my profound gratitude to my project advisor Dr. Gizachew Alemayehu. I would also like to thank Prof. Wendimagegn