Chemical and biological investigation of the Antarctic red

100 Pages·2015·2.38 MB·English

by  Santhisree Nandiraju

University of South Florida
Scholar Commons
Graduate Theses and Dissertations Graduate School
7-9-2004
Chemical and Biological Investigation of the
Antarctic Red Alga Delisea pulchra
Santhisree Nandiraju
University of South Florida
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Dissertations.
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Chemical and Biological Investigation of the Antarctic Red Alga Delisea pulchra

by

Santhisree Nandiraju

A thesis submitted in partial fulfillment
of the requirements for the degree of
Master of Science
Department of Chemistry
College of Arts and Sciences
University of South Florida

Major Professor: Bill J. Baker, Ph.D.
Edward Turos, Ph.D.
Kirpal Bisht, Ph.D.

Date of Approval:
July 9th, 2004

Keywords: furanones, Pulchralide, dimer, secondary metabolites, antifouling

@ Copyright 2004, Santhisree Nandiraju
DEDICATION

This thesis is dedicated to my beloved mother Mrs. Lakshmi Gouri, who motivated
me to pursue this degree and accomplish my goals. I present this work as a token of
appreciation and gratitude for all her efforts. I would also like to dedicate this thesis
to my sisters for their encouragement and inspiration at all times.
ACKNOWLEDGMENTS

I wish to express my sincerest thanks to my adviser Dr. Bill J. Baker, for his wise
counsel, viable guidance and constant encouragement and for ensuring the successful
culmination of this thesis.
I would like to thank Dr. James B. McClintock and Dr. Charles D. Amsler at the
University of Alabama, Birmingham for their help in the field work as well as in the
laboratory. I would like to thank Dr. Steven Mullen at the University of Illinois,
Urbana-Champaign, for the mass spectral data. I wish to thank Dr. Maya P. Singh
from Wyeth Pharmaceuticals and Dr. Fred Valeriote from Ford hospital for their
bioactivity data.
I would like to acknowledge my committee members, Dr. Kirpal Bisht and Dr.
Edward Turos for their encouragement and assistance. I am thankful to Dr. Baker’s
students for their timely help during my research work. Last but not the least I wish to
acknowledge my friends and roommates for the lighter moments, I have shared with
them.
TABLE OF CONTENTS

LIST OF FIGURES ……………………………………………………………..……….iii

LIST OF TABLES ………………………………………………………..……………...vi

LIST OF SCHEMES ……………………………………………………………………vii

LIST OF ABBREVATIONS …………………………………………………………...viii

ABSTRACT…………………………………………………………………………….....x

CHAPTER 1. INTRODUCTION…………………………………………………………1

1.1. Marine Natural Products……………………………………………………...1

1.2. Antarctic Ecology and Chemistry………………………………………….....9

CHAPTER 2. CHEMICAL INVESTIGATION OF THE ANTARCTIC RED ALGA

DELISEA PULCHRA……………………………………………………14

2.1. Introduction …………………………………………………………………14

2.2. Extraction and Isolation of Secondary Metabolites………….…...................17

2.3. Characterization of Fimbrolide (21)………………………………………...19

2.4. Characterization of Acetoxyfimbrolide (22)………………………………...22

2.5. Characterization of Hydroxyfimbrolide (23)………………………………..25

2.6. Characterization of Halogenated ketone 40…………………………………28

2.7. Characterization of Pulchralide A (41)……………………………………...31

2.8. Characterization of Pulchralide B (42)……………………………………...39
i
2.9. Characterization of Pulchralide C (43)……………………………………...44

CHAPTER 3. DISCUSSION…………………………………………………………….49

3.1. Biological Importance of Halogenated Metabolites of Delisea pulchra……49
3.2. Origin of Halogenated Metabolites of Delisea pulchra……………………..51
3.3. Ecological Importance of Halogenated Metabolites of Delisea pulchra……52
CHAPTER 4. EXPERIMENTAL………………………………………………………..54
4.1. General Experimental Procedure……………………………………………54
4.2. Bioassay of Pure Compounds…………………………………………….....56
4.3. Isolation of Secondary Metabolites from Delisea pulchra……………….....58
4.2.1. Spectral data of Fimbrolide (21)………………………………..........59

4.2.2. Spectral data of Acetoxyfimbrolide (22)…………………………….60

4.2.3. Spectral data of Hydroxyfimbrolide (23)…………………………….61

4.2.4. Spectral data of Halogenated ketone 40……………………………...62

4.2.5. Spectral data of Pulchralide A (41)…………………………………..63

4.2.6. Spectral data of Pulchralide B (42)…………………………………..64

4.2.7. Spectral data of Pulchralide C (43)…………………………………..65

REFERENCES…………………………………………………………………………..66

APPENDICES…………………………………………………………………………...73

ii
LIST OF FIGURES

Figure 1. The Antarctic Red alga Delisea pulchra……………………………………..15

Figure 2. 1H NMR spectrum of fimbrolide (21) (500 MHz, CDCl )…………………….19
3

Figure 3. 13C NMR spectrum of fimbrolide (21) (125 MHz, CDCl )…………………...20
3

Figure 4. 1H Chemical shift values of H-6 in Z and E isomers of fimbrolide (21) ……..21

Figure 5. 1H NMR spectrum of acetoxyfimbrolide (22) (250 MHz, CDCl )…………...22
3

Figure 6. 13C NMR spectrum of acetoxyfimbrolide (22) (62.5 MHz, CDCl )………….23
3

Figure 7. Acetoxyfimbrolide (22)……………………………………………………….24

Figure 8. 1H NMR spectrum of hydroxyfimbrolide (23) (250 MHz, CDCl )…………..26
3

Figure 9. 13C NMR spectrum of hydroxylfimbrolide (23) (125 MHz, CDCl )………....26
3

Figure 10. Hydroxyfimbrolide (23)……………………………………………………...27

Figure 11. 1H NMR spectrum of halogenated ketone 40 (250 MHz, CDCl )…………..28
3

Figure 12. 13C NMR spectrum of halogenated ketone 40 (62.5 MHz, CDCl )………….29
3

Figure 13. Halogenated ketone 40………………………………………………….........30

Figure 14. 1H NMR spectrum of pulchralide A (41) (500 MHz, CDCl )………………..32
3

Figure 15. 13C NMR spectrum of pulchralide A (41) (125 MHz, CDCl )……………….32
3

Figure 16. DEPT-135 spectrum of pulchralide A (41) (125 MHz, CDCl )……………..33
3

Figure 17. gCOSY spectrum of pulchralide A (41) (500 MHz, CDCl )………………..34
3

Figure 18. 1H-1H COSY correlations of pulchralide A (41)…………………………….34
iii
Figure 19. gHMQC spectrum of pulchralide A (41) (500MHz, CDCl )………………...35
3

Figure 20. gHMBC spectrum of pulchralide A (41) (500 MHz, CDCl3)………………36

Figure 21. KEY HMBC correlations determined in pulchralide A (41)………………...36

Figure 22. Perspective view of X-ray crystal structure of pulchralide A (41)…………..37
Figure 23. Sterochemical assignments of pulchralide A (41)…………………………...38
Figure 24. 1H NMR spectrum of pulchralide B (42) (500 MHz CDCl )………………..39
3

Figure 25. 13C NMR spectrum of pulchralide B (42) (125 MHz, CDCl )………………40
3

Figure 26. DEPT-135 spectrum of pulchralide B (42) (125 MHz CDCl )……………...41
3

Figure 27. gHMBC spectrum of pulchralide B (42) (500 MHz, CDCl )……………...42
3

Figure 28. Key HMBC correlation of pulchralide B (42)……………………………….42

Figure 29. Pulchralide B C dimer and pulchralide B meso dimer……………………..43
2

Figure 30. 1H NMR spectrum of pulchralide C (43) (500 MHz, CDCl )……………….45
3

Figure 31. 13C NMR spectrum of pulchralide B (43) (125 MHz CDCl )………………45
3

Figure 32. 1H-1H COSY spectrum of pulchralide C (43) (500 MHz, CDCl )..................46
3

Figure 33. Key 1H-1H COSY correlation of pulchralide C (27)………………………...47
Figure 34. stereo chemical assignments of pulchralide C (27)………………………….48
Figure 35. IR spectrum of fimbrolide (21)………………………………………………74
Figure 36. UV spectrum of fimbrolide (22)……………………………………………...74
Figure 37. LREI Mass spectrum of fimbrolide (23)……………………………………..75
Figure 38. IR spectrum of acetoxyfimbrolide (22)………………………………………75
Figure 39. UV spectrum of acetoxyfimbrolide (22)……………………………………..76
Figure 40. LREI Mass spectrum of Acetoxyfimbrolide (22)…………………………….76
iv
Figure 41. IR spectrum of hydroxyfimbrolide (23)……………………………………...77
Figure 42. UV spectrum of hydroxyfimbrolide (23)…………………………………….77
Figure 43. IR spectrum of halogenated ketone 40……………………………………….78
Figure 44. UV spectrum of halogenated ketone 40……………………………………...78
Figure 45. LREI Mass spectrum of halogenated ketone 40…………………………......79
Figure 46. IR spectrum of pulchralide A (41)……………………………………………79
Figure 47. UV spectrum of pulchralide A (41)…………………………………………..80
Figure 48. LREI Mass spectrum of pulchralide A (41)………………………………….80
Figure 49. gCOSY spectrum of pulchrlalide B (42) (500 MHz, CDCl )………………..81
3
Figure 50. gHMQC spectrum of pulchralide B (42) (500 MHz, CDCl )………………..81
3
Figure 51. IR spectrum of pulchralide B (42)……………………………………………82
Figure 52. UV spectrum of pulchralide B (42)…………………………………………..82
Figure 53. LRESI Mass spectrum of pulchralide B (42)………………………………..83
Figure 54. gHMQC spectrum of pulchralide C (43) (500 MHz CDCl )………………...83
3
Figure 55. gHMBC spectrum of pulchralide C (43) (500 MHz, CDCl )………………..84
3
Figure 56. IR spectrum of pulchralide C (43)……………………………………………84
Figure 57. UV spectrum of pulchralide C (43)…………………………………………..85
Figure 58. LREI Mass spectrum of pulchralide C (43)………………………………….85

v
LIST OF TABLES

Table 1. NMR data of pulchralide A (41) (CDCl )
3
(13C, 125 MHz; 1H, 500 MHz)………………………………………………..37

Table 2. NMR data of pulchralide B (42) (CDCl )
3
(13C, 125 MHz; 1H, 500 MHz)………………………………………………..43

Table 3. NMR data of pulchralide C (43) (CDCl )
3
(13C, 125 MHz; 1H, 500 MHz)………………………………………………..47

Table 4. Antimicrobial activity of pure compounds (100 µg/disk) using the disk
diffusion assay (Zone of Inhibition in mm)…………………………………...50

vi