Phytochemical and cytotoxicity studies on Arbutus pavarii, Asphodelus aestivus, Juniperus phoenicea and Ruta chalepensis growing in Libya Afaf Mohamed Al Groshi A thesis submitted in fulfilment of the requirements of Liverpool John Moores University for the degree of Doctor of Philosophy February 2019 ABSTRACT The work incorporates systematic bioassay-guided phytochemical and cytotoxicity/anticancer studies on four selected medicinal plants from the Libyan flora. Based on information on their traditional medicinal uses and the literature survey, Juniperus phoenicea L. (Fam: Cupressaceae), Asphodelus aestivus Brot. (Fam: Asphodelaceae), Ruta chalepensis. L (Fam: Rutaceae) and Arbutus pavarii Pampan. (Fam: Ericaceae) have been selected for investigation in the current endeavour. The four plants are well-known Libyan medicinal plants, which have been used in Libyan traditional medicine for the treatment of various human ailments, including both tumours and cancers. The cytotoxic activity of the n-hexane, dichloromethane (DCM) and methanol (MeOH) extracts of these plants were assessed against five human tumour cell lines: urinary bladder cancer [EJ-138], liver hepatocellular carcinoma [HEPG2], lung cancer [A549], breast cancer [MCF7] and prostate cancer [PC3] cell lines. The cytotoxicity at different concentrations of these extracts (0, 0.8, 4, 20, 100 and 500 µg/mL) was evaluated by the MTT assay. The four plants showed notable cytotoxicity against the five aforementioned human tumour cell lines with different selectivity indexes on prostate cancer cells. Accordingly, the cytotoxic effect of various chromatographic fractions from the different extracts of these plants at different concentrations (0, 0.4, 2, 10, 50 and 250 µg/mL) revealed different cytotoxic properties. Twenty-nine compounds were isolated from different fractions of these plants: three bioflavonoids, amentoflavone (25), cupressoflavone (24) and sumaflavone (76); four diterpenes. 13-epi-cupressic acid (42), imbricatholic acid (41), 3-hydroxy sandaracopimaric acid (44) and dehydroabietic acid (46), one alkanol (heptacosanol) i and two lignans, deoxypodophyllotoxin (29) and β-peltatin methyl ether (28)] from J. phoenicea leaves; one flavonoid, luteolin (22), four anthraquinones [aleo-emodin (13), chrysphanol anthrone (79), 10, 10`chrysphanol bianthrone (80) and C-α- rhamnopyranosyl bianthracene-9, 9’, 10 (10'H)-trione glycoside (81) and p-hydroxy- phenethyl trans-ferulate (82) from A. aestivus leaves and tubers; three alkaloids, kokusaginine (61), graveoline (60), and 4-hydroxy-2-nonyl-quinoline (85), three coumarins, bergapten (63), chalepin (64) and chalepensin (65), one alkane, tetradecane, two flavonoid glycosides, rutin (52) and methoxy rutin (83) and 3``, 6`- disinapoylsucrose (84) from R. chalepensis aerial parts; one hydroquinone- -D- glucopyranoside, arbutin (53) and two pentacyclic triterpenes, methyl betulinate (89) and ursolic acid (88) from A. pavarii leaves. Twenty-three isolated compounds were tested for their cytotoxicity against the most sensitive cancer cell lines. Eight compounds revealed good cytotoxic activity: cupressoflavone (24), sumaflavone (76), epicupressic acid (42), luteolin (22), chalepin (64) and 4-hydroxy-2-nonyl-quinoline (85) were cytotoxic against the A549 with IC50 values of 65, 77, 159, 76.9, 92 and 97.6 µM, respectively, whilst, compound 64 showed toxicity also against EJ138 with an IC50 value of 117 µM. C-α- rhamnopyranosyl bianthracene-9, 9’, 10 (10'H)-trione (81) and ursolic acid (88) were toxic against the prostate cancer cell line with IC50 values of 62 µM and 8.22 µM, respectively. The study findings also indicated that compounds 24, 64 and 88-induced cell death might involve the plasma membrane damage resulting in the release of LDH enzyme from the necrotic cells. ii DEDICATION I would like to dedicate my thesis to my beloved late mother Fatma Elamin El Gadamsi. Although she is no longer here with us to celebrate this achievement, she waited patiently for this day to come. She taught me great resilience when she fought against cancer multiple times, I learnt not to give up and work hard until I achieve what I desired for and although her loss was a heart breaker, I am glad that I made her proud. iii ACKNOWLEDGEMENTS Firstly, I would like to thank my God, the most gracious and merciful for supporting me and giving me the strength to carry on this study. I gratefully acknowledged the Libyan Government for the PhD scholarship. My deep gratitude to my supervisor Prof Satya Sarker for his continuous support, patience, motivation, immense knowledge and guidance in all the stages of my research and in the writing of my thesis. My profound gratitude is expressed to my supervisors: Dr Andrew Evans and Dr Fyaz Ismail whose help and support were the main reason of my development and who provided me with assistance, and perceptive comments in all the stages of this research. I would like to express my deep and sincere gratitude to my advisor Dr Lutfun Nahar for her suggestions, guidance, encouragement and support throughout this study. I would also like to acknowledge the EPSRC National Mass Spectrometry Service, Swansea, UK for MS analyses of my samples. Many thanks go to Dr Nicola Dempster and Mr. Robert Allen for their always help to run my NMR and MS samples. Special thanks go to Mr Daniel Graham for his assistance all the times. Thanks also extend to all my colleagues who helped me during this work and shared with them the best memories, namely; Mrs Laila Kafu, Miss Georgiana Alexander, Mrs Shaymaa Al Majmaie, Miss Hiba El Jasim, Miss Ruba Bunyan, Dr. Stephanie Tamdem, Dr. Sammar El Taib and Dr Sushmitta Nuth. I would also like to thank all the staff members of the department of school of pharmacy and bimolecular sciences to everyone who supported me in my research in the Liverpool John Moores University. To my dear husband Mr. Khalifa Garoushi, for his assistance, encouragement, and support all the times. He made my dream real. I am so grateful to him. My sisters and brothers I cannot imagine my life without you. Always find you when I need any help. Thanks for always being there for me. It is my pleasure to convey thanks to my son in law Mr. Soufian Al Bougdadi for his help and support. Last, but certainly not least, they are the beginning of everything beautiful in my life, my lovely, daughters Amel, Amna and Hager and my sweetheart son Anas. iv Contents Contents Page No. Abstract I Dedication III Acknowledgments IV List of figures XI List of tables XXII List of abbreviations XXVII Chapter 1: Introduction 1.1 Cancer 1 1.1.1 History of cancer 1 1.1.2 Incidence of cancer 2 1.1.3 Anticancer natural products 4 1.1.4 Mechanism of action of anticancer natural products 9 1.1.4.1 Mechanisms of cell death 9 1.1.4.2 Classification of anticancer agents according to their 9 chemical structure and mechanism of action 1.2 The family Asphodelaceae 13 1.2.1 Classification of the family Asphodelaceae 13 1.2.2 Chemical characteristics of the family Asphodelaceae 14 1.2.3 Traditional uses of the family Asphodelaceae 14 1.2.4 The genus Asphodelus L. 14 1.2.4.1 Active constituents of the genus Asphodelus 15 1.2.4.2 Traditional uses of the genus Asphodelus 15 1.2.5 Asphodelus aestivus Brot. 15 1.2.5.1 Traditional uses of A. aestivus 16 1.2.5.2 Previous phytochemical work of A. aestivus 16 1.2.5.3 Previous biological work of A. aestivus 19 1.3 The family Cupressaceae 21 1.3.1 Classification of the Cupressaceae 21 1.3.2 Chemical characteristics of the Cupressaceae family 22 1.3.3 Traditional uses of the Cupressaceae 22 v 1.3.4 The genus Juniperus L. 23 1.3.4.1 Species of the genus Juniperus 23 1.3.4.2 Active constituents in the genus Juniperus 23 1.3.4.3 Traditional uses of the genus Juniperus 24 1.3.5 Juniperus phoenicea L. 24 1.3.5.1 Traditional uses of J. phoenicea 25 1.3.5.2 Previous phytochemical work of J. phoenicea 26 1.3.5.3 Previous biological work of J. phoenicea 31 1.4 The family Ericaceae 35 1.4.1 Traditional uses of the family Ericaceae 35 1.4.2 The genus Arbutus L. 36 1.4.2.1 Active constituents in the genus Arbutus 36 1.4.2.2 Traditional uses of the genus Arbutus 36 1.4.3 Arbutus pavarii Pamp. 36 1.4.3.1 Traditional uses of A. pavarii 37 1.4.3.2 Previous phytochemical work of A. pavarii 37 1.4.3.3 Previous biological work of A. pavarii 39 1.5 The family Rutaceae 42 1.5.1 Classification of the family Rutaceae 42 1.5.2 Chemical characteristics of the family Rutaceae 43 1.5.3 Traditional uses of the family Rutaceae 43 1.5.4 The genus Ruta 43 1.5.4.1 Active constituents in the Ruta genus 44 1.5.4.2 Traditional uses of the genus Ruta 44 1.5.5 Ruta chalepensis L. 45 1.5.5.1 Traditional uses of R. chalepensis 45 1.5.5.2 Previous phytochemical work of R. chalepensis 46 1.5.5.3 Previous biological work of R. chalepensis 49 1.6 Objectives of this study 55 Chapter 2: Materials and Methods 2.1 Phytochemical work 58 2.1.1 General materials 58 vi 2.1.2 Plant materials 58 2.1.3 Extraction of plant materials 59 2.1.4 Fractionation techniques 59 2.1.4.1 Solid phase extraction (SPE) 59 2.1.4.2 Vacuum liquid chromatography (VLC) 60 2.1.5 Chromatographic techniques 61 2.1.5.1 Thin layer chromatography (TLC) 61 2.1.5.2 Column liquid chromatography (CLC) 62 2.1.6 Spectroscopic techniques 64 2.1.6.1 Ultraviolet-visible spectroscopy (UV-Vis) 64 2.1.6.2 Mass spectrometry (MS) 64 2.1.6.3 Nuclear magnetic resonance (NMR) 66 2.1.6.3.1 2.